CVE-2022-50549: 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---