Commit 31fa985b authored by Zqiang's avatar Zqiang Committed by Linus Torvalds
Browse files

kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time 

kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/
destroy().  The kasan_quarantine_remove_cache() call is protected by
cpuslock in kmem_cache_destroy() to ensure serialization with
kasan_cpu_offline().

However the kasan_quarantine_remove_cache() call is not protected by
cpuslock in kmem_cache_shrink().  When a CPU is going offline and cache
shrink occurs at same time, the cpu_quarantine may be corrupted by
interrupt (per_cpu_remove_cache operation).

So add a cpu_quarantine offline flags check in per_cpu_remove_cache().

[akpm@linux-foundation.org: add comment, per Zqiang]

Link: https://lkml.kernel.org/r/20220414025925.2423818-1-qiang1.zhang@intel.com


Signed-off-by: default avatarZqiang <qiang1.zhang@intel.com>
Reviewed-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d615b541

mm/kasan/quarantine.c

+7 −0
Original line number Diff line number Diff line
@@ -315,6 +315,13 @@ static void per_cpu_remove_cache(void *arg) 
	struct qlist_head *q;



	q = this_cpu_ptr(&cpu_quarantine);

	/*

	 * Ensure the ordering between the writing to q->offline and

	 * per_cpu_remove_cache.  Prevent cpu_quarantine from being corrupted

	 * by interrupt.

	 */

	if (READ_ONCE(q->offline))

		return;

	qlist_move_cache(q, &to_free, cache);

	qlist_free_all(&to_free, cache);

}