linux/drivers/block
Mikulas Patocka d0a255e795 loop: set PF_MEMALLOC_NOIO for the worker thread
A deadlock with this stacktrace was observed.

The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio
shrinker and the shrinker depends on I/O completion in the dm-bufio
subsystem.

In order to fix the deadlock (and other similar ones), we set the flag
PF_MEMALLOC_NOIO at loop thread entry.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

  PID: 14127  TASK: ffff881455749c00  CPU: 11  COMMAND: "loop1"
   #0 [ffff88272f5af228] __schedule at ffffffff8173f405
   #1 [ffff88272f5af280] schedule at ffffffff8173fa27
   #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e
   #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5
   #4 [ffff88272f5af330] mutex_lock at ffffffff81742133
   #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio]
   #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd
   #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778
   #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34
   #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8
  #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3
  #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71
  #12 [ffff88272f5af760] new_slab at ffffffff811f4523
  #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5
  #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b
  #15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3
  #16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3
  #17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs]
  #18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994
  #19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs]
  #20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop]
  #21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop]
  #22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c
  #23 [ffff88272f5afec0] kthread at ffffffff810a8428
  #24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-08 10:12:21 -06:00
..
aoe block: aoe: Fix kernel crash due to atomic sleep when exiting 2019-08-08 07:29:02 -06:00
drbd drbd: dynamically allocate shash descriptor 2019-07-23 07:35:18 -06:00
mtip32xx block: mtip32xx: Remove call to memset after dma_alloc_coherent 2019-06-29 09:42:50 -06:00
paride Linux 5.1-rc6 2019-04-22 09:47:36 -06:00
rsxx rsxx: don't call dma_set_max_seg_size 2019-06-05 13:18:39 -06:00
xen-blkback treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
zram docs: blockdev: add it to the admin-guide 2019-07-15 11:03:01 -03:00
Kconfig docs: blockdev: add it to the admin-guide 2019-07-15 11:03:01 -03:00
Makefile drivers/block: Remove DAC960 driver 2018-10-17 09:42:30 -06:00
amiflop.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
ataflop.c ataflop: Mark expected switch fall-through 2019-07-29 15:24:58 -06:00
brd.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
cryptoloop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 30 2019-05-24 17:27:10 +02:00
floppy.c Merge branch 'floppy' 2019-07-18 08:43:20 -07:00
loop.c loop: set PF_MEMALLOC_NOIO for the worker thread 2019-08-08 10:12:21 -06:00
loop.h block/loop: Use global lock for ioctl() operation. 2018-11-08 06:30:11 -07:00
nbd.c nbd: replace kill_bdev() with __invalidate_device() again 2019-07-31 08:51:56 -06:00
null_blk.h null_blk: fixup ->report_zones() for !CONFIG_BLK_DEV_ZONED 2019-07-12 09:09:57 -06:00
null_blk_main.c null_blk: fix type mismatch null_handle_cmd() 2019-06-29 09:36:37 -06:00
null_blk_zoned.c block: Kill gfp_t argument of blkdev_report_zones() 2019-07-11 20:04:37 -06:00
pktcdvd.c block: genhd: remove async_events field 2019-04-12 13:35:22 -06:00
ps3disk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 164 2019-05-30 11:26:38 -07:00
ps3vram.c block/ps3vram: Use %llu to format sector_t after LBDAF removal 2019-06-13 03:17:50 -06:00
rbd.c Lots of exciting things this time! 2019-07-18 11:05:25 -07:00
rbd_types.h rbd: support for object-map and fast-diff 2019-07-08 14:01:45 +02:00
skd_main.c Linux 5.2-rc6 2019-07-01 08:16:08 -06:00
skd_s1120.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
sunvdc.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
swim.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim3.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim_asm.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sx8.c sx8: use a per-host tag_set 2018-11-09 08:14:14 -07:00
umem.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 349 2019-06-05 17:37:08 +02:00
umem.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 348 2019-06-05 17:37:08 +02:00
virtio_blk.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
xen-blkfront.c xen-blkfront: switch kcalloc to kvcalloc for large array allocation 2019-06-03 22:16:19 -04:00
xsysace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
z2ram.c powerpc updates for 4.20 2018-10-26 14:36:21 -07:00