The patch titled
memcg: fix wrong pointer initialization at page migration when memcg is disabled.
has been added to the -mm tree. Its filename is
memcg-fix-wrong-pointer-initialization-at-page-migration-when-memcg-is-disabled.patch
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------------------------------------------------------
Subject: memcg: fix wrong pointer initialization at page migration when memcg is disabled.
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Lee Schermerhorn reported that he saw bad pointer dereference in
mem_cgroup_end_migration() when he disabled memcg by boot option.
memcg's page migration logic works as
mem_cgroup_prepare_migration(page, &ptr);
do page migration
mem_cgroup_end_migration(page, ptr);
Now, ptr is not initialized in prepare_migration when memcg is disabled
by boot option. This causes panic in end_migration. This patch fixes it.
Reported-by: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Reviewed-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-fix-wrong-pointer-initialization-at-page-migration-when-memcg-is-disabled mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-fix-wrong-pointer-initialization-at-page-migration-when-memcg-is-disabled
+++ a/mm/memcontrol.c
@@ -1990,7 +1990,8 @@ int mem_cgroup_prepare_migration(struct
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
int ret = 0;
-
+ /* this pointer will be checked at end_migration */
+ *ptr = NULL;
if (mem_cgroup_disabled())
return 0;
_
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
mm-dont-call-pte_unmap-against-an-improper-pte.patch
mm-add-notifier-in-pageblock-isolation-for-balloon-drivers.patch
powerpc-make-the-cmm-memory-hotplug-aware.patch
memcg-fix-wrong-pointer-initialization-at-page-migration-when-memcg-is-disabled.patch
mmap-dont-return-enomem-when-mapcount-is-temporarily-exceeded-in-munmap.patch
nodemask-make-nodemask_alloc-more-general.patch
hugetlb-rework-hstate_next_node_-functions.patch
hugetlb-add-nodemask-arg-to-huge-page-alloc-free-and-surplus-adjust-functions.patch
hugetlb-add-nodemask-arg-to-huge-page-alloc-free-and-surplus-adjust-functions-fix.patch
hugetlb-factor-init_nodemask_of_node.patch
hugetlb-derive-huge-pages-nodes-allowed-from-task-mempolicy.patch
hugetlb-add-generic-definition-of-numa_no_node.patch
hugetlb-add-per-node-hstate-attributes.patch
hugetlb-update-hugetlb-documentation-for-numa-controls.patch
hugetlb-use-only-nodes-with-memory-for-huge-pages.patch
mm-clear-node-in-n_high_memory-and-stop-kswapd-when-all-memory-is-offlined.patch
hugetlb-handle-memory-hot-plug-events.patch
hugetlb-offload-per-node-attribute-registrations.patch
mm-add-gfp-flags-for-nodemask_alloc-slab-allocations.patch
swap_info-private-to-swapfilec.patch
swap_info-change-to-array-of-pointers.patch
swap_info-include-first_swap_extent.patch
swap_info-miscellaneous-minor-cleanups.patch
swap_info-swap_has_cache-cleanups.patch
swap_info-swap_map-of-chars-not-shorts.patch
swap_info-swap-count-continuations.patch
swap_info-note-swap_map_shmem.patch
swap_info-reorder-its-fields.patch
memcg-coalesce-uncharge-during-unmap-truncate.patch
memcg-coalesce-charging-via-percpu-storage.patch
memcg-coalesce-charging-via-percpu-storage-fix.patch
memcg-coalesce-charging-via-percpu-storage-fix-2.patch
memcg-make-memcgs-file-mapped-consistent-with-global-vm.patch
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