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* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner2019-06-192-9/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499Thomas Gleixner2019-06-193-9/+3
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this work is licensed under the terms of the gnu gpl version 2 see the copying file in the top level directory extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 35 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482Thomas Gleixner2019-06-193-6/+3
| | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this work is licensed under the terms of the gnu gpl version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 48 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081204.624030236@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 248Thomas Gleixner2019-06-191-2/+1
| | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this file is released under the gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204655.103854853@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2019-06-161-6/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "The accumulated fixes from this and last week: - Fix vmalloc TLB flush and map range calculations which lead to stale TLBs, spurious faults and other hard to diagnose issues. - Use fault_in_pages_writable() for prefaulting the user stack in the FPU code as it's less fragile than the current solution - Use the PF_KTHREAD flag when checking for a kernel thread instead of current->mm as the latter can give the wrong answer due to use_mm() - Compute the vmemmap size correctly for KASLR and 5-Level paging. Otherwise this can end up with a way too small vmemmap area. - Make KASAN and 5-level paging work again by making sure that all invalid bits are masked out when computing the P4D offset. This worked before but got broken recently when the LDT remap area was moved. - Prevent a NULL pointer dereference in the resource control code which can be triggered with certain mount options when the requested resource is not available. - Enforce ordering of microcode loading vs. perf initialization on secondary CPUs. Otherwise perf tries to access a non-existing MSR as the boot CPU marked it as available. - Don't stop the resource control group walk early otherwise the control bitmaps are not updated correctly and become inconsistent. - Unbreak kgdb by returning 0 on success from kgdb_arch_set_breakpoint() instead of an error code. - Add more Icelake CPU model defines so depending changes can be queued in other trees" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/microcode, cpuhotplug: Add a microcode loader CPU hotplug callback x86/kasan: Fix boot with 5-level paging and KASAN x86/fpu: Don't use current->mm to check for a kthread x86/kgdb: Return 0 from kgdb_arch_set_breakpoint() x86/resctrl: Prevent NULL pointer dereference when local MBM is disabled x86/resctrl: Don't stop walking closids when a locksetup group is found x86/fpu: Update kernel's FPU state before using for the fsave header x86/mm/KASLR: Compute the size of the vmemmap section properly x86/fpu: Use fault_in_pages_writeable() for pre-faulting x86/CPU: Add more Icelake model numbers mm/vmalloc: Avoid rare case of flushing TLB with weird arguments mm/vmalloc: Fix calculation of direct map addr range
| * mm/vmalloc: Avoid rare case of flushing TLB with weird argumentsRick Edgecombe2019-06-031-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a rare case, flush_tlb_kernel_range() could be called with a start higher than the end. In vm_remove_mappings(), in case page_address() returns 0 for all pages (for example they were all in highmem), _vm_unmap_aliases() will be called with start = ULONG_MAX, end = 0 and flush = 1. If at the same time, the vmalloc purge operation is triggered by something else while the current operation is between remove_vm_area() and _vm_unmap_aliases(), then the vm mapping just removed will be already purged. In this case the call of vm_unmap_aliases() may not find any other mappings to flush and so end up flushing start = ULONG_MAX, end = 0. So only set flush = true if we find something in the direct mapping that we need to flush, and this way this can't happen. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Meelis Roos <mroos@linux.ee> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 868b104d7379 ("mm/vmalloc: Add flag for freeing of special permsissions") Link: https://lkml.kernel.org/r/20190527211058.2729-3-rick.p.edgecombe@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * mm/vmalloc: Fix calculation of direct map addr rangeRick Edgecombe2019-06-031-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The calculation of the direct map address range to flush was wrong. This could cause the RO direct map alias to not get flushed. Today this shouldn't be a problem because this flush is only needed on x86 right now and the spurious fault handler will fix cached RO->RW translations. In the future though, it could cause the permissions to remain RO in the TLB for the direct map alias, and then the page would return from the page allocator to some other component as RO and cause a crash. So fix fix the address range calculation so the flush will include the direct map range. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Meelis Roos <mroos@linux.ee> Cc: Nadav Amit <namit@vmware.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 868b104d7379 ("mm/vmalloc: Add flag for freeing of special permsissions") Link: https://lkml.kernel.org/r/20190527211058.2729-2-rick.p.edgecombe@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | mm/devm_memremap_pages: fix final page put raceDan Williams2019-06-131-11/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Logan noticed that devm_memremap_pages_release() kills the percpu_ref drops all the page references that were acquired at init and then immediately proceeds to unplug, arch_remove_memory(), the backing pages for the pagemap. If for some reason device shutdown actually collides with a busy / elevated-ref-count page then arch_remove_memory() should be deferred until after that reference is dropped. As it stands the "wait for last page ref drop" happens *after* devm_memremap_pages_release() returns, which is obviously too late and can lead to crashes. Fix this situation by assigning the responsibility to wait for the percpu_ref to go idle to devm_memremap_pages() with a new ->cleanup() callback. Implement the new cleanup callback for all devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma. Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 41e94a851304 ("add devm_memremap_pages") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/vmscan.c: fix trying to reclaim unevictable LRU pageMinchan Kim2019-06-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There was the below bug report from Wu Fangsuo. On the CMA allocation path, isolate_migratepages_range() could isolate unevictable LRU pages and reclaim_clean_page_from_list() can try to reclaim them if they are clean file-backed pages. page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24 flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked) raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053 raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80 page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page)) page->mem_cgroup:ffffffc09bf3ee80 ------------[ cut here ]------------ kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S 4.14.81 #3 Hardware name: ASR AQUILAC EVB (DT) task: ffffffc00a54cd00 task.stack: ffffffc009b00000 PC is at shrink_page_list+0x1998/0x3240 LR is at shrink_page_list+0x1998/0x3240 pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045 sp : ffffffc009b05940 .. shrink_page_list+0x1998/0x3240 reclaim_clean_pages_from_list+0x3c0/0x4f0 alloc_contig_range+0x3bc/0x650 cma_alloc+0x214/0x668 ion_cma_allocate+0x98/0x1d8 ion_alloc+0x200/0x7e0 ion_ioctl+0x18c/0x378 do_vfs_ioctl+0x17c/0x1780 SyS_ioctl+0xac/0xc0 Wu found it's due to commit ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu"). Before that, unevictable pages go to cull_mlocked so that we can't reach the VM_BUG_ON_PAGE line. To fix the issue, this patch filters out unevictable LRU pages from the reclaim_clean_pages_from_list in CMA. Link: http://lkml.kernel.org/r/20190524071114.74202-1-minchan@kernel.org Fixes: ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu") Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Wu Fangsuo <fangsuowu@asrmicro.com> Debugged-by: Wu Fangsuo <fangsuowu@asrmicro.com> Tested-by: Wu Fangsuo <fangsuowu@asrmicro.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Pankaj Suryawanshi <pankaj.suryawanshi@einfochips.com> Cc: <stable@vger.kernel.org> [4.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | coredump: fix race condition between collapse_huge_page() and core dumpingAndrea Arcangeli2019-06-131-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When fixing the race conditions between the coredump and the mmap_sem holders outside the context of the process, we focused on mmget_not_zero()/get_task_mm() callers in 04f5866e41fb70 ("coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping"), but those aren't the only cases where the mmap_sem can be taken outside of the context of the process as Michal Hocko noticed while backporting that commit to older -stable kernels. If mmgrab() is called in the context of the process, but then the mm_count reference is transferred outside the context of the process, that can also be a problem if the mmap_sem has to be taken for writing through that mm_count reference. khugepaged registration calls mmgrab() in the context of the process, but the mmap_sem for writing is taken later in the context of the khugepaged kernel thread. collapse_huge_page() after taking the mmap_sem for writing doesn't modify any vma, so it's not obvious that it could cause a problem to the coredump, but it happens to modify the pmd in a way that breaks an invariant that pmd_trans_huge_lock() relies upon. collapse_huge_page() needs the mmap_sem for writing just to block concurrent page faults that call pmd_trans_huge_lock(). Specifically the invariant that "!pmd_trans_huge()" cannot become a "pmd_trans_huge()" doesn't hold while collapse_huge_page() runs. The coredump will call __get_user_pages() without mmap_sem for reading, which eventually can invoke a lockless page fault which will need a functional pmd_trans_huge_lock(). So collapse_huge_page() needs to use mmget_still_valid() to check it's not running concurrently with the coredump... as long as the coredump can invoke page faults without holding the mmap_sem for reading. This has "Fixes: khugepaged" to facilitate backporting, but in my view it's more a bug in the coredump code that will eventually have to be rewritten to stop invoking page faults without the mmap_sem for reading. So the long term plan is still to drop all mmget_still_valid(). Link: http://lkml.kernel.org/r/20190607161558.32104-1-aarcange@redhat.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Peter Xu <peterx@redhat.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mlock.c: change count_mm_mlocked_page_nr return typeswkhack2019-06-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On a 64-bit machine the value of "vma->vm_end - vma->vm_start" may be negative when using 32 bit ints and the "count >> PAGE_SHIFT"'s result will be wrong. So change the local variable and return value to unsigned long to fix the problem. Link: http://lkml.kernel.org/r/20190513023701.83056-1-swkhack@gmail.com Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size") Signed-off-by: swkhack <swkhack@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: mmu_gather: remove __tlb_reset_range() for force flushYang Shi2019-06-131-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A few new fields were added to mmu_gather to make TLB flush smarter for huge page by telling what level of page table is changed. __tlb_reset_range() is used to reset all these page table state to unchanged, which is called by TLB flush for parallel mapping changes for the same range under non-exclusive lock (i.e. read mmap_sem). Before commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"), the syscalls (e.g. MADV_DONTNEED, MADV_FREE) which may update PTEs in parallel don't remove page tables. But, the forementioned commit may do munmap() under read mmap_sem and free page tables. This may result in program hang on aarch64 reported by Jan Stancek. The problem could be reproduced by his test program with slightly modified below. ---8<--- static int map_size = 4096; static int num_iter = 500; static long threads_total; static void *distant_area; void *map_write_unmap(void *ptr) { int *fd = ptr; unsigned char *map_address; int i, j = 0; for (i = 0; i < num_iter; i++) { map_address = mmap(distant_area, (size_t) map_size, PROT_WRITE | PROT_READ, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (map_address == MAP_FAILED) { perror("mmap"); exit(1); } for (j = 0; j < map_size; j++) map_address[j] = 'b'; if (munmap(map_address, map_size) == -1) { perror("munmap"); exit(1); } } return NULL; } void *dummy(void *ptr) { return NULL; } int main(void) { pthread_t thid[2]; /* hint for mmap in map_write_unmap() */ distant_area = mmap(0, DISTANT_MMAP_SIZE, PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); munmap(distant_area, (size_t)DISTANT_MMAP_SIZE); distant_area += DISTANT_MMAP_SIZE / 2; while (1) { pthread_create(&thid[0], NULL, map_write_unmap, NULL); pthread_create(&thid[1], NULL, dummy, NULL); pthread_join(thid[0], NULL); pthread_join(thid[1], NULL); } } ---8<--- The program may bring in parallel execution like below: t1 t2 munmap(map_address) downgrade_write(&mm->mmap_sem); unmap_region() tlb_gather_mmu() inc_tlb_flush_pending(tlb->mm); free_pgtables() tlb->freed_tables = 1 tlb->cleared_pmds = 1 pthread_exit() madvise(thread_stack, 8M, MADV_DONTNEED) zap_page_range() tlb_gather_mmu() inc_tlb_flush_pending(tlb->mm); tlb_finish_mmu() if (mm_tlb_flush_nested(tlb->mm)) __tlb_reset_range() __tlb_reset_range() would reset freed_tables and cleared_* bits, but this may cause inconsistency for munmap() which do free page tables. Then it may result in some architectures, e.g. aarch64, may not flush TLB completely as expected to have stale TLB entries remained. Use fullmm flush since it yields much better performance on aarch64 and non-fullmm doesn't yields significant difference on x86. The original proposed fix came from Jan Stancek who mainly debugged this issue, I just wrapped up everything together. Jan's testing results: v5.2-rc2-24-gbec7550cca10 -------------------------- mean stddev real 37.382 2.780 user 1.420 0.078 sys 54.658 1.855 v5.2-rc2-24-gbec7550cca10 + "mm: mmu_gather: remove __tlb_reset_range() for force flush" ---------------------------------------------------------------------------------------_ mean stddev real 37.119 2.105 user 1.548 0.087 sys 55.698 1.357 [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1558322252-113575-1-git-send-email-yang.shi@linux.alibaba.com Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Jan Stancek <jstancek@redhat.com> Reported-by: Jan Stancek <jstancek@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Suggested-by: Will Deacon <will.deacon@arm.com> Tested-by: Will Deacon <will.deacon@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Nick Piggin <npiggin@gmail.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: <stable@vger.kernel.org> [4.20+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/vmscan.c: fix recent_rotated historyKirill Tkhai2019-06-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Johannes pointed out that after commit 886cf1901db9 ("mm: move recent_rotated pages calculation to shrink_inactive_list()") we lost all zone_reclaim_stat::recent_rotated history. This fixes it. Link: http://lkml.kernel.org/r/155905972210.26456.11178359431724024112.stgit@localhost.localdomain Fixes: 886cf1901db9 ("mm: move recent_rotated pages calculation to shrink_inactive_list()") Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mlock.c: mlockall error for flag MCL_ONFAULTPotyra, Stefan2019-06-131-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If mlockall() is called with only MCL_ONFAULT as flag, it removes any previously applied lockings and does nothing else. This behavior is counter-intuitive and doesn't match the Linux man page. For mlockall(): EINVAL Unknown flags were specified or MCL_ONFAULT was specified without either MCL_FUTURE or MCL_CURRENT. Consequently, return the error EINVAL, if only MCL_ONFAULT is passed. That way, applications will at least detect that they are calling mlockall() incorrectly. Link: http://lkml.kernel.org/r/20190527075333.GA6339@er01809n.ebgroup.elektrobit.com Fixes: b0f205c2a308 ("mm: mlock: add mlock flags to enable VM_LOCKONFAULT usage") Signed-off-by: Stefan Potyra <Stefan.Potyra@elektrobit.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/list_lru.c: fix memory leak in __memcg_init_list_lru_nodeShakeel Butt2019-06-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syzbot reported following memory leak: ffffffffda RBX: 0000000000000003 RCX: 0000000000441f79 BUG: memory leak unreferenced object 0xffff888114f26040 (size 32): comm "syz-executor626", pid 7056, jiffies 4294948701 (age 39.410s) hex dump (first 32 bytes): 40 60 f2 14 81 88 ff ff 40 60 f2 14 81 88 ff ff @`......@`...... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: slab_post_alloc_hook mm/slab.h:439 [inline] slab_alloc mm/slab.c:3326 [inline] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553 kmalloc include/linux/slab.h:547 [inline] __memcg_init_list_lru_node+0x58/0xf0 mm/list_lru.c:352 memcg_init_list_lru_node mm/list_lru.c:375 [inline] memcg_init_list_lru mm/list_lru.c:459 [inline] __list_lru_init+0x193/0x2a0 mm/list_lru.c:626 alloc_super+0x2e0/0x310 fs/super.c:269 sget_userns+0x94/0x2a0 fs/super.c:609 sget+0x8d/0xb0 fs/super.c:660 mount_nodev+0x31/0xb0 fs/super.c:1387 fuse_mount+0x2d/0x40 fs/fuse/inode.c:1236 legacy_get_tree+0x27/0x80 fs/fs_context.c:661 vfs_get_tree+0x2e/0x120 fs/super.c:1476 do_new_mount fs/namespace.c:2790 [inline] do_mount+0x932/0xc50 fs/namespace.c:3110 ksys_mount+0xab/0x120 fs/namespace.c:3319 __do_sys_mount fs/namespace.c:3333 [inline] __se_sys_mount fs/namespace.c:3330 [inline] __x64_sys_mount+0x26/0x30 fs/namespace.c:3330 do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is a simple off by one bug on the error path. Link: http://lkml.kernel.org/r/20190528043202.99980-1-shakeelb@google.com Fixes: 60d3fd32a7a9 ("list_lru: introduce per-memcg lists") Reported-by: syzbot+f90a420dfe2b1b03cb2c@syzkaller.appspotmail.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: memcontrol: don't batch updates of local VM stats and eventsJohannes Weiner2019-06-131-13/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel test robot noticed a 26% will-it-scale pagefault regression from commit 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty"). This appears to be caused by bouncing the additional cachelines from the new hierarchical statistics counters. We can fix this by getting rid of the batched local counters instead. Originally, there were *only* group-local counters, and they were fully maintained per cpu. A reader of a stats file high up in the cgroup tree would have to walk the entire subtree and collect each level's per-cpu counters to get the recursive view. This was prohibitively expensive, and so we switched to per-cpu batched updates of the local counters during a983b5ebee57 ("mm: memcontrol: fix excessive complexity in memory.stat reporting"), reducing the complexity from nr_subgroups * nr_cpus to nr_subgroups. With growing machines and cgroup trees, the tree walk itself became too expensive for monitoring top-level groups, and this is when the culprit patch added hierarchy counters on each cgroup level. When the per-cpu batch size would be reached, both the local and the hierarchy counters would get batch-updated from the per-cpu delta simultaneously. This makes local and hierarchical counter reads blazingly fast, but it unfortunately makes the write-side too cache line intense. Since local counter reads were never a problem - we only centralized them to accelerate the hierarchy walk - and use of the local counters are becoming rarer due to replacement with hierarchical views (ongoing rework in the page reclaim and workingset code), we can make those local counters unbatched per-cpu counters again. The scheme will then be as such: when a memcg statistic changes, the writer will: - update the local counter (per-cpu) - update the batch counter (per-cpu). If the batch is full: - spill the batch into the group's atomic_t - spill the batch into all ancestors' atomic_ts - empty out the batch counter (per-cpu) when a local memcg counter is read, the reader will: - collect the local counter from all cpus when a hiearchy memcg counter is read, the reader will: - read the atomic_t We might be able to simplify this further and make the recursive counters unbatched per-cpu counters as well (batch upward propagation, but leave per-cpu collection to the readers), but that will require a more in-depth analysis and testing of all the callsites. Deal with the immediate regression for now. Link: http://lkml.kernel.org/r/20190521151647.GB2870@cmpxchg.org Fixes: 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: kernel test robot <rong.a.chen@intel.com> Tested-by: kernel test robot <rong.a.chen@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441Thomas Gleixner2019-06-051-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428Thomas Gleixner2019-06-054-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this file is released under the gplv2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 68 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 403Thomas Gleixner2019-06-051-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this software may be redistributed and or modified under the terms of the gnu general public license gpl version 2 as published by the free software foundation extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190112.039124428@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333Thomas Gleixner2019-06-052-27/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 136 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 263Thomas Gleixner2019-06-051-4/+1
|/ | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this software may be redistributed and or modified under the terms of the gnu general public license gpl version 2 only as published by the free software foundation extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141333.676969322@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* mm, compaction: make sure we isolate a valid PFNSuzuki K Poulose2019-06-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we have holes in a normal memory zone, we could endup having cached_migrate_pfns which may not necessarily be valid, under heavy memory pressure with swapping enabled ( via __reset_isolation_suitable(), triggered by kswapd). Later if we fail to find a page via fast_isolate_freepages(), we may end up using the migrate_pfn we started the search with, as valid page. This could lead to accessing NULL pointer derefernces like below, due to an invalid mem_section pointer. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 [47/1825] Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp = 0000000082f94ae9 [0000000000000008] pgd=0000000000000000 Internal error: Oops: 96000004 [#1] SMP ... CPU: 10 PID: 6080 Comm: qemu-system-aar Not tainted 510-rc1+ #6 Hardware name: AmpereComputing(R) OSPREY EV-883832-X3-0001/OSPREY, BIOS 4819 09/25/2018 pstate: 60000005 (nZCv daif -PAN -UAO) pc : set_pfnblock_flags_mask+0x58/0xe8 lr : compaction_alloc+0x300/0x950 [...] Process qemu-system-aar (pid: 6080, stack limit = 0x0000000095070da5) Call trace: set_pfnblock_flags_mask+0x58/0xe8 compaction_alloc+0x300/0x950 migrate_pages+0x1a4/0xbb0 compact_zone+0x750/0xde8 compact_zone_order+0xd8/0x118 try_to_compact_pages+0xb4/0x290 __alloc_pages_direct_compact+0x84/0x1e0 __alloc_pages_nodemask+0x5e0/0xe18 alloc_pages_vma+0x1cc/0x210 do_huge_pmd_anonymous_page+0x108/0x7c8 __handle_mm_fault+0xdd4/0x1190 handle_mm_fault+0x114/0x1c0 __get_user_pages+0x198/0x3c0 get_user_pages_unlocked+0xb4/0x1d8 __gfn_to_pfn_memslot+0x12c/0x3b8 gfn_to_pfn_prot+0x4c/0x60 kvm_handle_guest_abort+0x4b0/0xcd8 handle_exit+0x140/0x1b8 kvm_arch_vcpu_ioctl_run+0x260/0x768 kvm_vcpu_ioctl+0x490/0x898 do_vfs_ioctl+0xc4/0x898 ksys_ioctl+0x8c/0xa0 __arm64_sys_ioctl+0x28/0x38 el0_svc_common+0x74/0x118 el0_svc_handler+0x38/0x78 el0_svc+0x8/0xc Code: f8607840 f100001f 8b011401 9a801020 (f9400400) ---[ end trace af6a35219325a9b6 ]--- The issue was reported on an arm64 server with 128GB with holes in the zone (e.g, [32GB@4GB, 96GB@544GB]), with a swap device enabled, while running 100 KVM guest instances. This patch fixes the issue by ensuring that the page belongs to a valid PFN when we fallback to using the lower limit of the scan range upon failure in fast_isolate_freepages(). Link: http://lkml.kernel.org/r/1558711908-15688-1-git-send-email-suzuki.poulose@arm.com Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target") Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reported-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan: initialize tag to 0xff in __kasan_kmallocNathan Chancellor2019-06-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | When building with -Wuninitialized and CONFIG_KASAN_SW_TAGS unset, Clang warns: mm/kasan/common.c:484:40: warning: variable 'tag' is uninitialized when used here [-Wuninitialized] kasan_unpoison_shadow(set_tag(object, tag), size); ^~~ set_tag ignores tag in this configuration but clang doesn't realize it at this point in its pipeline, as it points to arch_kasan_set_tag as being the point where it is used, which will later be expanded to (void *)(object) without a use of tag. Initialize tag to 0xff, as it removes this warning and doesn't change the meaning of the code. Link: https://github.com/ClangBuiltLinux/linux/issues/465 Link: http://lkml.kernel.org/r/20190502163057.6603-1-natechancellor@gmail.com Fixes: 7f94ffbc4c6a ("kasan: add hooks implementation for tag-based mode") Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* z3fold: fix sheduling while atomicVitaly Wool2019-06-011-5/+6
| | | | | | | | | | | | kmem_cache_alloc() may be called from z3fold_alloc() in atomic context, so we need to pass correct gfp flags to avoid "scheduling while atomic" bug. Link: http://lkml.kernel.org/r/20190523153245.119dfeed55927e8755250ddd@gmail.com Fixes: 7c2b8baa61fe5 ("mm/z3fold.c: add structure for buddy handles") Signed-off-by: Vitaly Wool <vitaly.vul@sony.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/gup: continue VM_FAULT_RETRY processing even for pre-faultsMike Rapoport2019-06-011-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When get_user_pages*() is called with pages = NULL, the processing of VM_FAULT_RETRY terminates early without actually retrying to fault-in all the pages. If the pages in the requested range belong to a VMA that has userfaultfd registered, handle_userfault() returns VM_FAULT_RETRY *after* user space has populated the page, but for the gup pre-fault case there's no actual retry and the caller will get no pages although they are present. This issue was uncovered when running post-copy memory restore in CRIU after d9c9ce34ed5c ("x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails"). After this change, the copying of FPU state to the sigframe switched from copy_to_user() variants which caused a real page fault to get_user_pages() with pages parameter set to NULL. In post-copy mode of CRIU, the destination memory is managed with userfaultfd and lack of the retry for pre-fault case in get_user_pages() causes a crash of the restored process. Making the pre-fault behavior of get_user_pages() the same as the "normal" one fixes the issue. Link: http://lkml.kernel.org/r/1557844195-18882-1-git-send-email-rppt@linux.ibm.com Fixes: d9c9ce34ed5c ("x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails") Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Tested-by: Andrei Vagin <avagin@gmail.com> [https://travis-ci.org/avagin/linux/builds/533184940] Tested-by: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Borislav Petkov <bp@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: make it work on sparse non-0-node systemsJiri Slaby2019-06-011-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a single node system with node 0 disabled: Scanning NUMA topology in Northbridge 24 Number of physical nodes 2 Skipping disabled node 0 Node 1 MemBase 0000000000000000 Limit 00000000fbff0000 NODE_DATA(1) allocated [mem 0xfbfda000-0xfbfeffff] This causes crashes in memcg when system boots: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 #PF error: [normal kernel read fault] ... RIP: 0010:list_lru_add+0x94/0x170 ... Call Trace: d_lru_add+0x44/0x50 dput.part.34+0xfc/0x110 __fput+0x108/0x230 task_work_run+0x9f/0xc0 exit_to_usermode_loop+0xf5/0x100 It is reproducible as far as 4.12. I did not try older kernels. You have to have a new enough systemd, e.g. 241 (the reason is unknown -- was not investigated). Cannot be reproduced with systemd 234. The system crashes because the size of lru array is never updated in memcg_update_all_list_lrus and the reads are past the zero-sized array, causing dereferences of random memory. The root cause are list_lru_memcg_aware checks in the list_lru code. The test in list_lru_memcg_aware is broken: it assumes node 0 is always present, but it is not true on some systems as can be seen above. So fix this by avoiding checks on node 0. Remember the memcg-awareness by a bool flag in struct list_lru. Link: http://lkml.kernel.org/r/20190522091940.3615-1-jslaby@suse.cz Fixes: 60d3fd32a7a9 ("list_lru: introduce per-memcg lists") Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* prctl_set_mm: downgrade mmap_sem to read lockMichal Koutný2019-06-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit a3b609ef9f8b ("proc read mm's {arg,env}_{start,end} with mmap semaphore taken.") added synchronization of reading argument/environment boundaries under mmap_sem. Later commit 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") avoided the coarse use of mmap_sem in similar situations. But there still remained two places that (mis)use mmap_sem. get_cmdline should also use arg_lock instead of mmap_sem when it reads the boundaries. The second place that should use arg_lock is in prctl_set_mm. By protecting the boundaries fields with the arg_lock, we can downgrade mmap_sem to reader lock (analogous to what we already do in prctl_set_mm_map). [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20190502125203.24014-3-mkoutny@suse.com Fixes: 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Co-developed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/vmalloc.c: fix typo in commentAndrew Morton2019-06-011-1/+1
| | | | | | Reported-by: Nicholas Joll <najoll@posteo.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 225Thomas Gleixner2019-05-301-1/+1
| | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): subject to the gnu public license version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171440.319650492@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157Thomas Gleixner2019-05-303-30/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 3 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner2019-05-303-15/+3
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98Thomas Gleixner2019-05-241-5/+1
| | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your optional any later version of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.713472955@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-212-0/+2
| | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Add SPDX license identifier for more missed filesThomas Gleixner2019-05-214-0/+4
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Add SPDX license identifier for missed filesThomas Gleixner2019-05-2122-0/+22
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2019-05-192-248/+851
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge yet more updates from Andrew Morton: "A few final bits: - large changes to vmalloc, yielding large performance benefits - tweak the console-flush-on-panic code - a few fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: panic: add an option to replay all the printk message in buffer initramfs: don't free a non-existent initrd fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going into workqueue when umount mm/compaction.c: correct zone boundary handling when isolating pages from a pageblock mm/vmap: add DEBUG_AUGMENT_LOWEST_MATCH_CHECK macro mm/vmap: add DEBUG_AUGMENT_PROPAGATE_CHECK macro mm/vmalloc.c: keep track of free blocks for vmap allocation
| * mm/compaction.c: correct zone boundary handling when isolating pages from a ↵Mel Gorman2019-05-181-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pageblock syzbot reported the following error from a tree with a head commit of baf76f0c58ae ("slip: make slhc_free() silently accept an error pointer") BUG: unable to handle kernel paging request at ffffea0003348000 #PF error: [normal kernel read fault] PGD 12c3f9067 P4D 12c3f9067 PUD 12c3f8067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 28916 Comm: syz-executor.2 Not tainted 5.1.0-rc6+ #89 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline] RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline] RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579 Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38 ff ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31 ff 49 c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246 RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000 RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001 RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000 R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000 FS: 00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0 Call Trace: fast_isolate_around mm/compaction.c:1243 [inline] fast_isolate_freepages mm/compaction.c:1418 [inline] isolate_freepages mm/compaction.c:1438 [inline] compaction_alloc+0x1aee/0x22e0 mm/compaction.c:1550 There is no reproducer and it is difficult to hit -- 1 crash every few days. The issue is very similar to the fix in commit 6b0868c820ff ("mm/compaction.c: correct zone boundary handling when resetting pageblock skip hints"). When isolating free pages around a target pageblock, the boundary handling is off by one and can stray into the next pageblock. Triggering the syzbot error requires that the end of pageblock is section or zone aligned, and that the next section is unpopulated. A more subtle consequence of the bug is that pageblocks were being improperly used as migration targets which potentially hurts fragmentation avoidance in the long-term one page at a time. A debugging patch revealed that it's definitely possible to stray outside of a pageblock which is not intended. While syzbot cannot be used to verify this patch, it was confirmed that the debugging warning no longer triggers with this patch applied. It has also been confirmed that the THP allocation stress tests are not degraded by this patch. Link: http://lkml.kernel.org/r/20190510182124.GI18914@techsingularity.net Fixes: e332f741a8dd ("mm, compaction: be selective about what pageblocks to clear skip hints") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: syzbot+d84c80f9fe26a0f7a734@syzkaller.appspotmail.com Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Qian Cai <cai@lca.pw> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> # v5.1+ Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm/vmap: add DEBUG_AUGMENT_LOWEST_MATCH_CHECK macroUladzislau Rezki (Sony)2019-05-181-0/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This macro adds some debug code to check that vmap allocations are happened in ascending order. By default this option is set to 0 and not active. It requires recompilation of the kernel to activate it. Set to 1, compile the kernel. [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-4-urezki@gmail.com Link: http://lkml.kernel.org/r/20190402162531.10888-4-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joel Fernandes <joelaf@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm/vmap: add DEBUG_AUGMENT_PROPAGATE_CHECK macroUladzislau Rezki (Sony)2019-05-181-0/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This macro adds some debug code to check that the augment tree is maintained correctly, meaning that every node contains valid subtree_max_size value. By default this option is set to 0 and not active. It requires recompilation of the kernel to activate it. Set to 1, compile the kernel. [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-3-urezki@gmail.com Link: http://lkml.kernel.org/r/20190402162531.10888-3-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joel Fernandes <joelaf@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm/vmalloc.c: keep track of free blocks for vmap allocationUladzislau Rezki (Sony)2019-05-181-246/+758
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "improve vmap allocation", v3. Objective --------- Please have a look for the description at: https://lkml.org/lkml/2018/10/19/786 but let me also summarize it a bit here as well. The current implementation has O(N) complexity. Requests with different permissive parameters can lead to long allocation time. When i say "long" i mean milliseconds. Description ----------- This approach organizes the KVA memory layout into free areas of the 1-ULONG_MAX range, i.e. an allocation is done over free areas lookups, instead of finding a hole between two busy blocks. It allows to have lower number of objects which represent the free space, therefore to have less fragmented memory allocator. Because free blocks are always as large as possible. It uses the augment tree where all free areas are sorted in ascending order of va->va_start address in pair with linked list that provides O(1) access to prev/next elements. Since the tree is augment, we also maintain the "subtree_max_size" of VA that reflects a maximum available free block in its left or right sub-tree. Knowing that, we can easily traversal toward the lowest (left most path) free area. Allocation: ~O(log(N)) complexity. It is sequential allocation method therefore tends to maximize locality. The search is done until a first suitable block is large enough to encompass the requested parameters. Bigger areas are split. I copy paste here the description of how the area is split, since i described it in https://lkml.org/lkml/2018/10/19/786 <snip> A free block can be split by three different ways. Their names are FL_FIT_TYPE, LE_FIT_TYPE/RE_FIT_TYPE and NE_FIT_TYPE, i.e. they correspond to how requested size and alignment fit to a free block. FL_FIT_TYPE - in this case a free block is just removed from the free list/tree because it fully fits. Comparing with current design there is an extra work with rb-tree updating. LE_FIT_TYPE/RE_FIT_TYPE - left/right edges fit. In this case what we do is just cutting a free block. It is as fast as a current design. Most of the vmalloc allocations just end up with this case, because the edge is always aligned to 1. NE_FIT_TYPE - Is much less common case. Basically it happens when requested size and alignment does not fit left nor right edges, i.e. it is between them. In this case during splitting we have to build a remaining left free area and place it back to the free list/tree. Comparing with current design there are two extra steps. First one is we have to allocate a new vmap_area structure. Second one we have to insert that remaining free block to the address sorted list/tree. In order to optimize a first case there is a cache with free_vmap objects. Instead of allocating from slab we just take an object from the cache and reuse it. Second one is pretty optimized. Since we know a start point in the tree we do not do a search from the top. Instead a traversal begins from a rb-tree node we split. <snip> De-allocation. ~O(log(N)) complexity. An area is not inserted straight away to the tree/list, instead we identify the spot first, checking if it can be merged around neighbors. The list provides O(1) access to prev/next, so it is pretty fast to check it. Summarizing. If merged then large coalesced areas are created, if not the area is just linked making more fragments. There is one more thing that i should mention here. After modification of VA node, its subtree_max_size is updated if it was/is the biggest area in its left or right sub-tree. Apart of that it can also be populated back to upper levels to fix the tree. For more details please have a look at the __augment_tree_propagate_from() function and the description. Tests and stressing ------------------- I use the "test_vmalloc.sh" test driver available under "tools/testing/selftests/vm/" since 5.1-rc1 kernel. Just trigger "sudo ./test_vmalloc.sh" to find out how to deal with it. Tested on different platforms including x86_64/i686/ARM64/x86_64_NUMA. Regarding last one, i do not have any physical access to NUMA system, therefore i emulated it. The time of stressing is days. If you run the test driver in "stress mode", you also need the patch that is in Andrew's tree but not in Linux 5.1-rc1. So, please apply it: http://git.cmpxchg.org/cgit.cgi/linux-mmotm.git/commit/?id=e0cf7749bade6da318e98e934a24d8b62fab512c After massive testing, i have not identified any problems like memory leaks, crashes or kernel panics. I find it stable, but more testing would be good. Performance analysis -------------------- I have used two systems to test. One is i5-3320M CPU @ 2.60GHz and another is HiKey960(arm64) board. i5-3320M runs on 4.20 kernel, whereas Hikey960 uses 4.15 kernel. I have both system which could run on 5.1-rc1 as well, but the results have not been ready by time i an writing this. Currently it consist of 8 tests. There are three of them which correspond to different types of splitting(to compare with default). We have 3 ones(see above). Another 5 do allocations in different conditions. a) sudo ./test_vmalloc.sh performance When the test driver is run in "performance" mode, it runs all available tests pinned to first online CPU with sequential execution test order. We do it in order to get stable and repeatable results. Take a look at time difference in "long_busy_list_alloc_test". It is not surprising because the worst case is O(N). # i5-3320M How many cycles all tests took: CPU0=646919905370(default) cycles vs CPU0=193290498550(patched) cycles # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_patched.txt # Hikey960 8x CPUs How many cycles all tests took: CPU0=3478683207 cycles vs CPU0=463767978 cycles # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_patched.txt b) time sudo ./test_vmalloc.sh test_repeat_count=1 With this configuration, all tests are run on all available online CPUs. Before running each CPU shuffles its tests execution order. It gives random allocation behaviour. So it is rough comparison, but it puts in the picture for sure. # i5-3320M <default> vs <patched> real 101m22.813s real 0m56.805s user 0m0.011s user 0m0.015s sys 0m5.076s sys 0m0.023s # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_patched.txt # Hikey960 8x CPUs <default> vs <patched> real unknown real 4m25.214s user unknown user 0m0.011s sys unknown sys 0m0.670s I did not manage to complete this test on "default Hikey960" kernel version. After 24 hours it was still running, therefore i had to cancel it. That is why real/user/sys are "unknown". This patch (of 3): Currently an allocation of the new vmap area is done over busy list iteration(complexity O(n)) until a suitable hole is found between two busy areas. Therefore each new allocation causes the list being grown. Due to over fragmented list and different permissive parameters an allocation can take a long time. For example on embedded devices it is milliseconds. This patch organizes the KVA memory layout into free areas of the 1-ULONG_MAX range. It uses an augment red-black tree that keeps blocks sorted by their offsets in pair with linked list keeping the free space in order of increasing addresses. Nodes are augmented with the size of the maximum available free block in its left or right sub-tree. Thus, that allows to take a decision and traversal toward the block that will fit and will have the lowest start address, i.e. it is sequential allocation. Allocation: to allocate a new block a search is done over the tree until a suitable lowest(left most) block is large enough to encompass: the requested size, alignment and vstart point. If the block is bigger than requested size - it is split. De-allocation: when a busy vmap area is freed it can either be merged or inserted to the tree. Red-black tree allows efficiently find a spot whereas a linked list provides a constant-time access to previous and next blocks to check if merging can be done. In case of merging of de-allocated memory chunk a large coalesced area is created. Complexity: ~O(log(N)) [urezki@gmail.com: v3] Link: http://lkml.kernel.org/r/20190402162531.10888-2-urezki@gmail.com [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-2-urezki@gmail.com Link: http://lkml.kernel.org/r/20190321190327.11813-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Joel Fernandes <joelaf@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2019-05-191-7/+8
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core fixes from Ingo Molnar: "This fixes a particularly thorny munmap() bug with MPX, plus fixes a host build environment assumption in objtool" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Allow AR to be overridden with HOSTAR x86/mpx, mm/core: Fix recursive munmap() corruption
| * x86/mpx, mm/core: Fix recursive munmap() corruptionDave Hansen2019-05-091-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a bit of a mess, to put it mildly. But, it's a bug that only seems to have showed up in 4.20 but wasn't noticed until now, because nobody uses MPX. MPX has the arch_unmap() hook inside of munmap() because MPX uses bounds tables that protect other areas of memory. When memory is unmapped, there is also a need to unmap the MPX bounds tables. Barring this, unused bounds tables can eat 80% of the address space. But, the recursive do_munmap() that gets called vi arch_unmap() wreaks havoc with __do_munmap()'s state. It can result in freeing populated page tables, accessing bogus VMA state, double-freed VMAs and more. See the "long story" further below for the gory details. To fix this, call arch_unmap() before __do_unmap() has a chance to do anything meaningful. Also, remove the 'vma' argument and force the MPX code to do its own, independent VMA lookup. == UML / unicore32 impact == Remove unused 'vma' argument to arch_unmap(). No functional change. I compile tested this on UML but not unicore32. == powerpc impact == powerpc uses arch_unmap() well to watch for munmap() on the VDSO and zeroes out 'current->mm->context.vdso_base'. Moving arch_unmap() makes this happen earlier in __do_munmap(). But, 'vdso_base' seems to only be used in perf and in the signal delivery that happens near the return to userspace. I can not find any likely impact to powerpc, other than the zeroing happening a little earlier. powerpc does not use the 'vma' argument and is unaffected by its removal. I compile-tested a 64-bit powerpc defconfig. == x86 impact == For the common success case this is functionally identical to what was there before. For the munmap() failure case, it's possible that some MPX tables will be zapped for memory that continues to be in use. But, this is an extraordinarily unlikely scenario and the harm would be that MPX provides no protection since the bounds table got reset (zeroed). I can't imagine anyone doing this: ptr = mmap(); // use ptr ret = munmap(ptr); if (ret) // oh, there was an error, I'll // keep using ptr. Because if you're doing munmap(), you are *done* with the memory. There's probably no good data in there _anyway_. This passes the original reproducer from Richard Biener as well as the existing mpx selftests/. The long story: munmap() has a couple of pieces: 1. Find the affected VMA(s) 2. Split the start/end one(s) if neceesary 3. Pull the VMAs out of the rbtree 4. Actually zap the memory via unmap_region(), including freeing page tables (or queueing them to be freed). 5. Fix up some of the accounting (like fput()) and actually free the VMA itself. This specific ordering was actually introduced by: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") during the 4.20 merge window. The previous __do_munmap() code was actually safe because the only thing after arch_unmap() was remove_vma_list(). arch_unmap() could not see 'vma' in the rbtree because it was detached, so it is not even capable of doing operations unsafe for remove_vma_list()'s use of 'vma'. Richard Biener reported a test that shows this in dmesg: [1216548.787498] BUG: Bad rss-counter state mm:0000000017ce560b idx:1 val:551 [1216548.787500] BUG: non-zero pgtables_bytes on freeing mm: 24576 What triggered this was the recursive do_munmap() called via arch_unmap(). It was freeing page tables that has not been properly zapped. But, the problem was bigger than this. For one, arch_unmap() can free VMAs. But, the calling __do_munmap() has variables that *point* to VMAs and obviously can't handle them just getting freed while the pointer is still in use. I tried a couple of things here. First, I tried to fix the page table freeing problem in isolation, but I then found the VMA issue. I also tried having the MPX code return a flag if it modified the rbtree which would force __do_munmap() to re-walk to restart. That spiralled out of control in complexity pretty fast. Just moving arch_unmap() and accepting that the bonkers failure case might eat some bounds tables seems like the simplest viable fix. This was also reported in the following kernel bugzilla entry: https://bugzilla.kernel.org/show_bug.cgi?id=203123 There are some reports that this commit triggered this bug: dd2283f2605 ("mm: mmap: zap pages with read mmap_sem in munmap") While that commit certainly made the issues easier to hit, I believe the fundamental issue has been with us as long as MPX itself, thus the Fixes: tag below is for one of the original MPX commits. [ mingo: Minor edits to the changelog and the patch. ] Reported-by: Richard Biener <rguenther@suse.de> Reported-by: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-um@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@vger.kernel.org Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Link: http://lkml.kernel.org/r/20190419194747.5E1AD6DC@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | slab: remove /proc/slab_allocatorsQian Cai2019-05-161-225/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turned out that DEBUG_SLAB_LEAK is still broken even after recent recue efforts that when there is a large number of objects like kmemleak_object which is normal on a debug kernel, # grep kmemleak /proc/slabinfo kmemleak_object 2243606 3436210 ... reading /proc/slab_allocators could easily loop forever while processing the kmemleak_object cache and any additional freeing or allocating objects will trigger a reprocessing. To make a situation worse, soft-lockups could easily happen in this sitatuion which will call printk() to allocate more kmemleak objects to guarantee an infinite loop. Also, since it seems no one had noticed when it was totally broken more than 2-year ago - see the commit fcf88917dd43 ("slab: fix a crash by reading /proc/slab_allocators"), probably nobody cares about it anymore due to the decline of the SLAB. Just remove it entirely. Suggested-by: Vlastimil Babka <vbabka@suse.cz> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: memcontrol: fix NUMA round-robin reclaim at intermediate levelJohannes Weiner2019-05-141-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a cgroup is reclaimed on behalf of a configured limit, reclaim needs to round-robin through all NUMA nodes that hold pages of the memcg in question. However, when assembling the mask of candidate NUMA nodes, the code only consults the *local* cgroup LRU counters, not the recursive counters for the entire subtree. Cgroup limits are frequently configured against intermediate cgroups that do not have memory on their own LRUs. In this case, the node mask will always come up empty and reclaim falls back to scanning only the current node. If a cgroup subtree has some memory on one node but the processes are bound to another node afterwards, the limit reclaim will never age or reclaim that memory anymore. To fix this, use the recursive LRU counts for a cgroup subtree to determine which nodes hold memory of that cgroup. The code has been broken like this forever, so it doesn't seem to be a problem in practice. I just noticed it while reviewing the way the LRU counters are used in general. Link: http://lkml.kernel.org/r/20190412151507.2769-5-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: memcontrol: fix recursive statistics correctness & scalabiltyJohannes Weiner2019-05-141-106/+99
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now, when somebody needs to know the recursive memory statistics and events of a cgroup subtree, they need to walk the entire subtree and sum up the counters manually. There are two issues with this: 1. When a cgroup gets deleted, its stats are lost. The state counters should all be 0 at that point, of course, but the events are not. When this happens, the event counters, which are supposed to be monotonic, can go backwards in the parent cgroups. 2. During regular operation, we always have a certain number of lazily freed cgroups sitting around that have been deleted, have no tasks, but have a few cache pages remaining. These groups' statistics do not change until we eventually hit memory pressure, but somebody watching, say, memory.stat on an ancestor has to iterate those every time. This patch addresses both issues by introducing recursive counters at each level that are propagated from the write side when stats change. Upward propagation happens when the per-cpu caches spill over into the local atomic counter. This is the same thing we do during charge and uncharge, except that the latter uses atomic RMWs, which are more expensive; stat changes happen at around the same rate. In a sparse file test (page faults and reclaim at maximum CPU speed) with 5 cgroup nesting levels, perf shows __mod_memcg_page state at ~1%. Link: http://lkml.kernel.org/r/20190412151507.2769-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: memcontrol: move stat/event counting functions out-of-lineJohannes Weiner2019-05-141-0/+79
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These are getting too big to be inlined in every callsite. They were stolen from vmstat.c, which already out-of-lines them, and they have only been growing since. The callsites aren't that hot, either. Move __mod_memcg_state() __mod_lruvec_state() and __count_memcg_events() out of line and add kerneldoc comments. Link: http://lkml.kernel.org/r/20190412151507.2769-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: memcontrol: make cgroup stats and events query API explicitly localJohannes Weiner2019-05-143-25/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm: memcontrol: memory.stat cost & correctness". The cgroup memory.stat file holds recursive statistics for the entire subtree. The current implementation does this tree walk on-demand whenever the file is read. This is giving us problems in production. 1. The cost of aggregating the statistics on-demand is high. A lot of system service cgroups are mostly idle and their stats don't change between reads, yet we always have to check them. There are also always some lazily-dying cgroups sitting around that are pinned by a handful of remaining page cache; the same applies to them. In an application that periodically monitors memory.stat in our fleet, we have seen the aggregation consume up to 5% CPU time. 2. When cgroups die and disappear from the cgroup tree, so do their accumulated vm events. The result is that the event counters at higher-level cgroups can go backwards and confuse some of our automation, let alone people looking at the graphs over time. To address both issues, this patch series changes the stat implementation to spill counts upwards when the counters change. The upward spilling is batched using the existing per-cpu cache. In a sparse file stress test with 5 level cgroup nesting, the additional cost of the flushing was negligible (a little under 1% of CPU at 100% CPU utilization, compared to the 5% of reading memory.stat during regular operation). This patch (of 4): memcg_page_state(), lruvec_page_state(), memcg_sum_events() are currently returning the state of the local memcg or lruvec, not the recursive state. In practice there is a demand for both versions, although the callers that want the recursive counts currently sum them up by hand. Per default, cgroups are considered recursive entities and generally we expect more users of the recursive counters, with the local counts being special cases. To reflect that in the name, add a _local suffix to the current implementations. The following patch will re-incarnate these functions with recursive semantics, but with an O(1) implementation. [hannes@cmpxchg.org: fix bisection hole] Link: http://lkml.kernel.org/r/20190417160347.GC23013@cmpxchg.org Link: http://lkml.kernel.org/r/20190412151507.2769-2-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, memcg: rename ambiguously named memory.stat counters and functionsChris Down2019-05-141-72/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I spent literally an hour trying to work out why an earlier version of my memory.events aggregation code doesn't work properly, only to find out I was calling memcg->events instead of memcg->memory_events, which is fairly confusing. This naming seems in need of reworking, so make it harder to do the wrong thing by using vmevents instead of events, which makes it more clear that these are vm counters rather than memcg-specific counters. There are also a few other inconsistent names in both the percpu and aggregated structs, so these are all cleaned up to be more coherent and easy to understand. This commit contains code cleanup only: there are no logic changes. [akpm@linux-foundation.org: fix it for preceding changes] Link: http://lkml.kernel.org/r/20190208224319.GA23801@chrisdown.name Signed-off-by: Chris Down <chris@chrisdown.name> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: Dennis Zhou <dennis@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mincore.c: make mincore() more conservativeJiri Kosina2019-05-141-1/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The semantics of what mincore() considers to be resident is not completely clear, but Linux has always (since 2.3.52, which is when mincore() was initially done) treated it as "page is available in page cache". That's potentially a problem, as that [in]directly exposes meta-information about pagecache / memory mapping state even about memory not strictly belonging to the process executing the syscall, opening possibilities for sidechannel attacks. Change the semantics of mincore() so that it only reveals pagecache information for non-anonymous mappings that belog to files that the calling process could (if it tried to) successfully open for writing; otherwise we'd be including shared non-exclusive mappings, which - is the sidechannel - is not the usecase for mincore(), as that's primarily used for data, not (shared) text [jkosina@suse.cz: v2] Link: http://lkml.kernel.org/r/20190312141708.6652-2-vbabka@suse.cz [mhocko@suse.com: restructure can_do_mincore() conditions] Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1903062342020.19912@cbobk.fhfr.pm Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Josh Snyder <joshs@netflix.com> Acked-by: Michal Hocko <mhocko@suse.com> Originally-by: Linus Torvalds <torvalds@linux-foundation.org> Originally-by: Dominique Martinet <asmadeus@codewreck.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Chinner <david@fromorbit.com> Cc: Kevin Easton <kevin@guarana.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Cyril Hrubis <chrubis@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daniel Gruss <daniel@gruss.cc> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: maintain randomization of page free listsDan Williams2019-05-143-2/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When freeing a page with an order >= shuffle_page_order randomly select the front or back of the list for insertion. While the mm tries to defragment physical pages into huge pages this can tend to make the page allocator more predictable over time. Inject the front-back randomness to preserve the initial randomness established by shuffle_free_memory() when the kernel was booted. The overhead of this manipulation is constrained by only being applied for MAX_ORDER sized pages by default. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/154899812788.3165233.9066631950746578517.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>