git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 31fa985b4196f8a66f027672e9bf2b81fea0417c Mon Sep 17 00:00:00 2001
   2 From: Zqiang <qiang1.zhang@intel.com>
   3 Date: Wed, 27 Apr 2022 12:41:56 -0700
   4 Subject: kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time
   5
   6 From: Zqiang <qiang1.zhang@intel.com>
   7
   8 commit 31fa985b4196f8a66f027672e9bf2b81fea0417c upstream.
   9
  10 kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/
  11 destroy().  The kasan_quarantine_remove_cache() call is protected by
  12 cpuslock in kmem_cache_destroy() to ensure serialization with
  13 kasan_cpu_offline().
  14
  15 However the kasan_quarantine_remove_cache() call is not protected by
  16 cpuslock in kmem_cache_shrink().  When a CPU is going offline and cache
  17 shrink occurs at same time, the cpu_quarantine may be corrupted by
  18 interrupt (per_cpu_remove_cache operation).
  19
  20 So add a cpu_quarantine offline flags check in per_cpu_remove_cache().
  21
  22 [akpm@linux-foundation.org: add comment, per Zqiang]
  23
  24 Link: https://lkml.kernel.org/r/20220414025925.2423818-1-qiang1.zhang@intel.com
  25 Signed-off-by: Zqiang <qiang1.zhang@intel.com>
  26 Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
  27 Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  28 Cc: Alexander Potapenko <glider@google.com>
  29 Cc: Andrey Konovalov <andreyknvl@gmail.com>
  30 Cc: <stable@vger.kernel.org>
  31 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  32 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  33 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  34 ---
  35  mm/kasan/quarantine.c |    7 +++++++
  36  1 file changed, 7 insertions(+)
  37
  38 --- a/mm/kasan/quarantine.c
  39 +++ b/mm/kasan/quarantine.c
  40 @@ -299,6 +299,13 @@ static void per_cpu_remove_cache(void *a
  41         struct qlist_head *q;
  42
  43         q = this_cpu_ptr(&cpu_quarantine);
  44 +       /*
  45 +        * Ensure the ordering between the writing to q->offline and
  46 +        * per_cpu_remove_cache.  Prevent cpu_quarantine from being corrupted
  47 +        * by interrupt.
  48 +        */
  49 +       if (READ_ONCE(q->offline))
  50 +               return;
  51         qlist_move_cache(q, &to_free, cache);
  52         qlist_free_all(&to_free, cache);
  53  }