dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata

In the Linux kernel, the following vulnerability has been resolved:

dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata

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

Funct

---truncated---