]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: slab: fix potential double free in ___cache_free
authorShakeel Butt <shakeelb@google.com>
Sat, 26 Sep 2020 14:13:41 +0000 (07:13 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 26 Sep 2020 17:15:01 +0000 (10:15 -0700)
commit678ff6a7afccc43d352c1b8c94b6d8c0ee1464ad
tree5e8da2d0d8687dc174f0987e8bd29a82e3ba73cd
parent7c7ec3226f5f33f9c050d85ec20f18419c622ad6
mm: slab: fix potential double free in ___cache_free

With the commit 10befea91b61 ("mm: memcg/slab: use a single set of
kmem_caches for all allocations"), it becomes possible to call kfree()
from the slabs_destroy().

The functions cache_flusharray() and do_drain() calls slabs_destroy() on
array_cache of the local CPU without updating the size of the
array_cache.  This enables the kfree() call from the slabs_destroy() to
recursively call cache_flusharray() which can potentially call
free_block() on the same elements of the array_cache of the local CPU
and causing double free and memory corruption.

To fix the issue, simply update the local CPU array_cache cache before
calling slabs_destroy().

Fixes: 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ted Ts'o <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/slab.c