lkml.org 
[lkml]   [2022]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] vmscan: fix potential arbitrary pointer passed to kfree in unregister_shrinker
Date
From: Jinjiang Tu <tujinjiang@bytedance.com>

when shrinker is registered with SHRINKER_MEMCG_AWARE flag,
register_shrinker will not initialize shrinker->nr_deferred,
but the pointer will be passed to kfree in unregister_shrinker
when the shrinker is unregistered. This leads to kernel crash
when the shrinker object is dynamically allocated.

To fix it, this patch initialize shrinker->nr_deferred at the
beginning of prealloc_shrinker.

Signed-off-by: Jinjiang Tu <tujinjiang@bytedance.com>
---
mm/vmscan.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f7d9a683e3a7..06ab5a398971 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -613,6 +613,7 @@ int prealloc_shrinker(struct shrinker *shrinker)
unsigned int size;
int err;

+ shrinker->nr_deferred = NULL;
if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
err = prealloc_memcg_shrinker(shrinker);
if (err != -ENOSYS)
--
2.17.1
\
 
 \ /
  Last update: 2022-07-27 11:09    [W:0.059 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site