Subject: + mm-memcg-use-proper-memcg-in-limit-bypass.patch added to -mm tree
To: hannes@xxxxxxxxxxx,mhocko@xxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 30 Oct 2013 15:12:47 -0700
The patch titled
Subject: mm: memcg: use proper memcg in limit bypass
has been added to the -mm tree. Its filename is
mm-memcg-use-proper-memcg-in-limit-bypass.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-use-proper-memcg-in-limit-bypass.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-use-proper-memcg-in-limit-bypass.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcg: use proper memcg in limit bypass
84235de ("fs: buffer: move allocation failure loop into the allocator")
allowed __GFP_NOFAIL allocations to bypass the limit if they fail to
reclaim enough memory for the charge. Because the main test case was on a
3.2-based system, this patch missed the fact that on newer kernels the
charge function needs to return root_mem_cgroup when bypassing the limit,
and not NULL. This will corrupt whatever memory is at NULL + percpu
pointer offset. Fix this quickly before problems are reported.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN mm/memcontrol.c~mm-memcg-use-proper-memcg-in-limit-bypass mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcg-use-proper-memcg-in-limit-bypass
+++ a/mm/memcontrol.c
@@ -2765,10 +2765,10 @@ done:
*ptr = memcg;
return 0;
nomem:
- *ptr = NULL;
- if (gfp_mask & __GFP_NOFAIL)
- return 0;
- return -ENOMEM;
+ if (!(gfp_mask & __GFP_NOFAIL)) {
+ *ptr = NULL;
+ return -ENOMEM;
+ }
bypass:
*ptr = root_mem_cgroup;
return -EINTR;
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
percpu-fix-this_cpu_sub-subtrahend-casting-for-unsigneds.patch
memcg-use-__this_cpu_sub-to-dec-stats-to-avoid-incorrect-subtrahend-casting.patch
mm-memcg-use-proper-memcg-in-limit-bypass.patch
mm-memcg-lockdep-annotation-for-memcg-oom-lock.patch
mm-memcg-fix-test-for-child-groups.patch
mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch
memcg-refactor-mem_control_numa_stat_show.patch
memcg-support-hierarchical-memorynuma_stats.patch
memblock-factor-out-of-top-down-allocation.patch
memblock-introduce-bottom-up-allocation-mode.patch
x86-mm-factor-out-of-top-down-direct-mapping-setup.patch
x86-mem-hotplug-support-initialize-page-tables-in-bottom-up.patch
x86-acpi-crash-kdump-do-reserve_crashkernel-after-srat-is-parsed.patch
mem-hotplug-introduce-movable_node-boot-option.patch
swap-add-a-simple-detector-for-inappropriate-swapin-readahead-fix.patch
percpu-add-test-module-for-various-percpu-operations.patch
linux-next.patch
mm-avoid-increase-sizeofstruct-page-due-to-split-page-table-lock.patch
mm-rename-use_split_ptlocks-to-use_split_pte_ptlocks.patch
mm-convert-mm-nr_ptes-to-atomic_long_t.patch
mm-introduce-api-for-split-page-table-lock-for-pmd-level.patch
mm-thp-change-pmd_trans_huge_lock-to-return-taken-lock.patch
mm-thp-move-ptl-taking-inside-page_check_address_pmd.patch
mm-thp-do-not-access-mm-pmd_huge_pte-directly.patch
mm-hugetlb-convert-hugetlbfs-to-use-split-pmd-lock.patch
mm-convert-the-rest-to-new-page-table-lock-api.patch
mm-implement-split-page-table-lock-for-pmd-level.patch
x86-mm-enable-split-page-table-lock-for-pmd-level.patch
debugging-keep-track-of-page-owners-fix-2-fix-fix-fix.patch
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