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authorAlexander Polakov <apolyakov@beget.ru>2016-10-27 17:46:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-10 16:36:32 +0100
commit9fa32e04f8107af05d6d557a27a4687ec02ff6e5 (patch)
tree0f95749a83e772e8439465eeeabc92dd3ab0882d /mm
parentfd9e4cea96df8dc759ce32fb5d1677d781caf244 (diff)
downloadlinux-linaro-stable-9fa32e04f8107af05d6d557a27a4687ec02ff6e5.tar.gz
mm/list_lru.c: avoid error-path NULL pointer deref
commit 1bc11d70b5db7c6bb1414b283d7f09b1fe1ac0d0 upstream. As described in https://bugzilla.kernel.org/show_bug.cgi?id=177821: After some analysis it seems to be that the problem is in alloc_super(). In case list_lru_init_memcg() fails it goes into destroy_super(), which calls list_lru_destroy(). And in list_lru_init() we see that in case memcg_init_list_lru() fails, lru->node is freed, but not set NULL, which then leads list_lru_destroy() to believe it is initialized and call memcg_destroy_list_lru(). memcg_destroy_list_lru() in turn can access lru->node[i].memcg_lrus, which is NULL. [akpm@linux-foundation.org: add comment] Signed-off-by: Alexander Polakov <apolyakov@beget.ru> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/list_lru.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c
index afc71ea9a381..5d8dffd5b57c 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -554,6 +554,8 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware,
err = memcg_init_list_lru(lru, memcg_aware);
if (err) {
kfree(lru->node);
+ /* Do this so a list_lru_destroy() doesn't crash: */
+ lru->node = NULL;
goto out;
}