lkml.org 
[lkml]   [2016]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.4 06/69] mm/list_lru.c: avoid error-path NULL pointer deref
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Polakov <apolyakov@beget.ru>

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>

---
mm/list_lru.c | 2 ++
1 file changed, 2 insertions(+)

--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -554,6 +554,8 @@ int __list_lru_init(struct list_lru *lru
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;
}


\
 
 \ /
  Last update: 2016-11-09 11:51    [W:0.465 / U:0.400 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site