queue-4.19/dm-integrity-fix-deadlock-with-overlapping-i-o.patch

   1 From 4ed319c6ac08e9a28fca7ac188181ac122f4de84 Mon Sep 17 00:00:00 2001
   2 From: Mikulas Patocka <mpatocka@redhat.com>
   3 Date: Fri, 5 Apr 2019 15:26:39 -0400
   4 Subject: dm integrity: fix deadlock with overlapping I/O
   5
   6 From: Mikulas Patocka <mpatocka@redhat.com>
   7
   8 commit 4ed319c6ac08e9a28fca7ac188181ac122f4de84 upstream.
   9
  10 dm-integrity will deadlock if overlapping I/O is issued to it, the bug
  11 was introduced by commit 724376a04d1a ("dm integrity: implement fair
  12 range locks").  Users rarely use overlapping I/O so this bug went
  13 undetected until now.
  14
  15 Fix this bug by correcting, likely cut-n-paste, typos in
  16 ranges_overlap() and also remove a flawed ranges_overlap() check in
  17 remove_range_unlocked().  This condition could leave unprocessed bios
  18 hanging on wait_list forever.
  19
  20 Cc: stable@vger.kernel.org # v4.19+
  21 Fixes: 724376a04d1a ("dm integrity: implement fair range locks")
  22 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
  23 Signed-off-by: Mike Snitzer <snitzer@redhat.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  drivers/md/dm-integrity.c |    4 +---
  28  1 file changed, 1 insertion(+), 3 deletions(-)
  29
  30 --- a/drivers/md/dm-integrity.c
  31 +++ b/drivers/md/dm-integrity.c
  32 @@ -908,7 +908,7 @@ static void copy_from_journal(struct dm_
  33  static bool ranges_overlap(struct dm_integrity_range *range1, struct dm_integrity_range *range2)
  34  {
  35         return range1->logical_sector < range2->logical_sector + range2->n_sectors &&
  36 -              range2->logical_sector + range2->n_sectors > range2->logical_sector;
  37 +              range1->logical_sector + range1->n_sectors > range2->logical_sector;
  38  }
  39
  40  static bool add_new_range(struct dm_integrity_c *ic, struct dm_integrity_range *new_range, bool check_waiting)
  41 @@ -954,8 +954,6 @@ static void remove_range_unlocked(struct
  42                 struct dm_integrity_range *last_range =
  43                         list_first_entry(&ic->wait_list, struct dm_integrity_range, wait_entry);
  44                 struct task_struct *last_range_task;
  45 -               if (!ranges_overlap(range, last_range))
  46 -                       break;
  47                 last_range_task = last_range->task;
  48                 list_del(&last_range->wait_entry);
  49                 if (!add_new_range(ic, last_range, false)) {