On Wed 30-10-13 15:12:47, Andrew Morton wrote: > 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 > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > The -mm tree is included into linux-next and is updated > there every 3-4 working days > > ------------------------------------------------------ > 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> Acked-by: Michal Hocko <mhocko@xxxxxxx> I guess this should be marked for stable as 84235de has been marked so. It would be also nice to mention that bypass with root_mem_cgroup happened at 3.3 times (it was done by 38c5d72f3ebe5 AFAICS). > --- > > 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 > -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>