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authorPekka Enberg <penberg@kernel.org>2010-11-08 21:29:07 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-09 10:19:38 -0800
commit63bfd7384b119409685a17d5c58f0b56e5dc03da (patch)
treeb01a10267b8e702af948e571801f02ee70ff1794 /mm
parent814ce2521121c2459e16cea8c7221e157edbeddd (diff)
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perf_events: Fix perf_counter_mmap() hook in mprotect()
As pointed out by Linus, commit dab5855 ("perf_counter: Add mmap event hooks to mprotect()") is fundamentally wrong as mprotect_fixup() can free 'vma' due to merging. Fix the problem by moving perf_event_mmap() hook to mprotect_fixup(). Note: there's another successful return path from mprotect_fixup() if old flags equal to new flags. We don't, however, need to call perf_event_mmap() there because 'perf' already knows the VMA is executable. Reported-by: Dave Jones <davej@redhat.com> Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mprotect.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 2d1bf7cf885..4c513387309 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -211,6 +211,7 @@ success:
mmu_notifier_invalidate_range_end(mm, start, end);
vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
vm_stat_account(mm, newflags, vma->vm_file, nrpages);
+ perf_event_mmap(vma);
return 0;
fail:
@@ -299,7 +300,6 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
if (error)
goto out;
- perf_event_mmap(vma);
nstart = tmp;
if (nstart < prev->vm_end)