Messages in this thread Patch in this message | | | From | tujinjiang@bytedanc ... | Subject | [PATCH] vmscan: fix potential arbitrary pointer passed to kfree in unregister_shrinker | Date | Wed, 27 Jul 2022 17:07:00 +0800 |
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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
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