From: Zqiang Date: Wed, 27 Apr 2022 19:41:56 +0000 (-0700) Subject: kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur... X-Git-Tag: v6.1-rc5~1485^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=31fa985b4196f8a66f027672e9bf2b81fea0417c;p=platform%2Fkernel%2Flinux-starfive.git 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: Zqiang Reviewed-by: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 08291ed..0a9def8 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -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); }