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authorzhong jiang <zhongjiang@huawei.com>2019-06-28 12:06:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-06-29 16:43:44 +0800
commit29b190fa774dd1b72a1a6f19687d55dc72ea83be (patch)
tree23f12a7ac48293428e8980c82516aae224cb1bb4
parentcb8f381f1613cafe3aec30809991cd56e7135d92 (diff)
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mm/mempolicy.c: fix an incorrect rebind node in mpol_rebind_nodemask
mpol_rebind_nodemask() is called for MPOL_BIND and MPOL_INTERLEAVE mempoclicies when the tasks's cpuset's mems_allowed changes. For policies created without MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES, it works by remapping the policy's allowed nodes (stored in v.nodes) using the previous value of mems_allowed (stored in w.cpuset_mems_allowed) as the domain of map and the new mems_allowed (passed as nodes) as the range of the map (see the comment of bitmap_remap() for details). The result of remapping is stored back as policy's nodemask in v.nodes, and the new value of mems_allowed should be stored in w.cpuset_mems_allowed to facilitate the next rebind, if it happens. However, 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies when updating cpusets") introduced a bug where the result of remapping is stored in w.cpuset_mems_allowed instead. Thus, a mempolicy's allowed nodes can evolve in an unexpected way after a series of rebinding due to cpuset mems_allowed changes, possibly binding to a wrong node or a smaller number of nodes which may e.g. overload them. This patch fixes the bug so rebinding again works as intended. [vbabka@suse.cz: new changlog] Link: http://lkml.kernel.org/r/ef6a69c6-c052-b067-8f2c-9d615c619bb9@suse.cz Link: http://lkml.kernel.org/r/1558768043-23184-1-git-send-email-zhongjiang@huawei.com Fixes: 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies when updating cpusets") Signed-off-by: zhong jiang <zhongjiang@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mempolicy.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 01600d80ae01..fdcb73536319 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -306,7 +306,7 @@ static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
else {
nodes_remap(tmp, pol->v.nodes,pol->w.cpuset_mems_allowed,
*nodes);
- pol->w.cpuset_mems_allowed = tmp;
+ pol->w.cpuset_mems_allowed = *nodes;
}
if (nodes_empty(tmp))