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Filename Latest commit message Latest commit date
Zhihao Cheng 200aa33b5d dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata
commit 8111964f1b8524c4bb56b02cd9c7a37725ea21fd upstream.

Following concurrent processes:

          P1(drop cache)                P2(kworker)
drop_caches_sysctl_handler
 drop_slab
  shrink_slab
   down_read(&shrinker_rwsem)  - LOCK A
   do_shrink_slab
    super_cache_scan
     prune_icache_sb
      dispose_list
       evict
        ext4_evict_inode
	 ext4_clear_inode
	  ext4_discard_preallocations
	   ext4_mb_load_buddy_gfp
	    ext4_mb_init_cache
	     ext4_read_block_bitmap_nowait
	      ext4_read_bh_nowait
	       submit_bh
	        dm_submit_bio
		                 do_worker
				  process_deferred_bios
				   commit
				    metadata_operation_failed
				     dm_pool_abort_metadata
				      down_write(&pmd->root_lock) - LOCK B
		                      __destroy_persistent_data_objects
				       dm_block_manager_destroy
				        dm_bufio_client_destroy
				         unregister_shrinker
					  down_write(&shrinker_rwsem)
		 thin_map                            |
		  dm_thin_find_block                 ↓
		   down_read(&pmd->root_lock) --> ABBA deadlock

, which triggers hung task:

[   76.974820] INFO: task kworker/u4:3:63 blocked for more than 15 seconds.
[   76.976019]       Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910
[   76.978521] task:kworker/u4:3    state:D stack:0     pid:63    ppid:2
[   76.978534] Workqueue: dm-thin do_worker
[   76.978552] Call Trace:
[   76.978564]  __schedule+0x6ba/0x10f0
[   76.978582]  schedule+0x9d/0x1e0
[   76.978588]  rwsem_down_write_slowpath+0x587/0xdf0
[   76.978600]  down_write+0xec/0x110
[   76.978607]  unregister_shrinker+0x2c/0xf0
[   76.978616]  dm_bufio_client_destroy+0x116/0x3d0
[   76.978625]  dm_block_manager_destroy+0x19/0x40
[   76.978629]  __destroy_persistent_data_objects+0x5e/0x70
[   76.978636]  dm_pool_abort_metadata+0x8e/0x100
[   76.978643]  metadata_operation_failed+0x86/0x110
[   76.978649]  commit+0x6a/0x230
[   76.978655]  do_worker+0xc6e/0xd90
[   76.978702]  process_one_work+0x269/0x630
[   76.978714]  worker_thread+0x266/0x630
[   76.978730]  kthread+0x151/0x1b0
[   76.978772] INFO: task test.sh:2646 blocked for more than 15 seconds.
[   76.979756]       Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910
[   76.982111] task:test.sh         state:D stack:0     pid:2646  ppid:2459
[   76.982128] Call Trace:
[   76.982139]  __schedule+0x6ba/0x10f0
[   76.982155]  schedule+0x9d/0x1e0
[   76.982159]  rwsem_down_read_slowpath+0x4f4/0x910
[   76.982173]  down_read+0x84/0x170
[   76.982177]  dm_thin_find_block+0x4c/0xd0
[   76.982183]  thin_map+0x201/0x3d0
[   76.982188]  __map_bio+0x5b/0x350
[   76.982195]  dm_submit_bio+0x2b6/0x930
[   76.982202]  __submit_bio+0x123/0x2d0
[   76.982209]  submit_bio_noacct_nocheck+0x101/0x3e0
[   76.982222]  submit_bio_noacct+0x389/0x770
[   76.982227]  submit_bio+0x50/0xc0
[   76.982232]  submit_bh_wbc+0x15e/0x230
[   76.982238]  submit_bh+0x14/0x20
[   76.982241]  ext4_read_bh_nowait+0xc5/0x130
[   76.982247]  ext4_read_block_bitmap_nowait+0x340/0xc60
[   76.982254]  ext4_mb_init_cache+0x1ce/0xdc0
[   76.982259]  ext4_mb_load_buddy_gfp+0x987/0xfa0
[   76.982263]  ext4_discard_preallocations+0x45d/0x830
[   76.982274]  ext4_clear_inode+0x48/0xf0
[   76.982280]  ext4_evict_inode+0xcf/0xc70
[   76.982285]  evict+0x119/0x2b0
[   76.982290]  dispose_list+0x43/0xa0
[   76.982294]  prune_icache_sb+0x64/0x90
[   76.982298]  super_cache_scan+0x155/0x210
[   76.982303]  do_shrink_slab+0x19e/0x4e0
[   76.982310]  shrink_slab+0x2bd/0x450
[   76.982317]  drop_slab+0xcc/0x1a0
[   76.982323]  drop_caches_sysctl_handler+0xb7/0xe0
[   76.982327]  proc_sys_call_handler+0x1bc/0x300
[   76.982331]  proc_sys_write+0x17/0x20
[   76.982334]  vfs_write+0x3d3/0x570
[   76.982342]  ksys_write+0x73/0x160
[   76.982347]  __x64_sys_write+0x1e/0x30
[   76.982352]  do_syscall_64+0x35/0x80
[   76.982357]  entry_SYSCALL_64_after_hwframe+0x63/0xcd

Function metadata_operation_failed() is called when operations failed
on dm pool metadata, dm pool will destroy and recreate metadata. So,
shrinker will be unregistered and registered, which could down write
shrinker_rwsem under pmd_write_lock.

Fix it by allocating dm_block_manager before locking pmd->root_lock
and destroying old dm_block_manager after unlocking pmd->root_lock,
then old dm_block_manager is replaced with new dm_block_manager under
pmd->root_lock. So, shrinker register/unregister could be done without
holding pmd->root_lock.

Fetch a reproducer in [Link].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216676
Cc: stable@vger.kernel.org #v5.2+
Fixes: e49e582965 ("dm thin: add read only and fail io modes")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:41:47 +01:00
arch binfmt: Move install_exec_creds after setup_new_exec to match binfmt_elf 2023-01-18 11:41:46 +01:00
block blk-mq: fix possible memleak when register 'hctx' failed 2023-01-18 11:41:38 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation ASoC: dt-bindings: wcd9335: fix reset line polarity in example 2023-01-18 11:41:06 +01:00
drivers dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata 2023-01-18 11:41:47 +01:00
fs binfmt: Fix error return code in load_elf_fdpic_binary() 2023-01-18 11:41:46 +01:00
include nvme: fix the NVME_CMD_EFFECTS_CSE_MASK definition 2023-01-18 11:41:43 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel gcov: add support for checksum field 2023-01-18 11:41:42 +01:00
lib test_firmware: fix memory leak in test_firmware_init() 2023-01-18 11:41:23 +01:00
LICENSES
mm mm, compaction: fix fast_isolate_around() to stay within boundaries 2023-01-18 11:41:44 +01:00
net net/af_packet: make sure to pull mac header 2023-01-18 11:41:45 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security apparmor: Use pointer to struct aa_label for lbs_cred 2023-01-18 11:41:17 +01:00
sound ALSA: line6: fix stack overflow in line6_midi_transmit 2023-01-18 11:41:44 +01:00
tools selftests: Use optional USERCFLAGS and USERLDFLAGS 2023-01-18 11:41:46 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
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Makefile Linux 5.4.228 2022-12-19 12:24:17 +01:00
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