WARNING: possible circular locking dependency detected 6.3.0-rc7-syzkaller-00181-g8e41e0a57566 #0 Not tainted ------------------------------------------------------ kswapd0/109 is trying to acquire lock: ffff888029196930 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] ffff888029196930 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_destroy_mark fs/notify/mark.c:496 [inline] ffff888029196930 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_destroy_marks+0x16a/0x4b0 fs/notify/mark.c:854 but task is already holding lock: ffffffff8c8e11c0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] ffffffff8c8e11c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4717 [inline] fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4731 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:728 [inline] slab_alloc_node mm/slab.c:3241 [inline] slab_alloc mm/slab.c:3266 [inline] __kmem_cache_alloc_lru mm/slab.c:3443 [inline] kmem_cache_alloc+0x3d/0x3f0 mm/slab.c:3452 inotify_new_watch fs/notify/inotify/inotify_user.c:600 [inline] inotify_update_watch+0x530/0xc30 fs/notify/inotify/inotify_user.c:648 __do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:787 [inline] __se_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:730 [inline] __x64_sys_inotify_add_watch+0x2bf/0x350 fs/notify/inotify/inotify_user.c:730 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&group->mark_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747 fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] fsnotify_destroy_mark fs/notify/mark.c:496 [inline] fsnotify_destroy_marks+0x16a/0x4b0 fs/notify/mark.c:854 fsnotify_inoderemove include/linux/fsnotify.h:193 [inline] dentry_unlink_inode+0x3aa/0x460 fs/dcache.c:397 __dentry_kill+0x3c0/0x640 fs/dcache.c:607 shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282 super_cache_scan+0x33a/0x590 fs/super.c:104 do_shrink_slab+0x428/0xaa0 mm/vmscan.c:853 shrink_slab_memcg mm/vmscan.c:922 [inline] shrink_slab+0x388/0x660 mm/vmscan.c:1001 shrink_one+0x502/0x810 mm/vmscan.c:5343 shrink_many mm/vmscan.c:5394 [inline] lru_gen_shrink_node mm/vmscan.c:5511 [inline] shrink_node+0x2064/0x35f0 mm/vmscan.c:6459 kswapd_shrink_node mm/vmscan.c:7262 [inline] balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452 kswapd+0x677/0xd60 mm/vmscan.c:7712 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&group->mark_mutex); lock(fs_reclaim); lock(&group->mark_mutex); *** DEADLOCK *** 3 locks held by kswapd0/109: #0: ffffffff8c8e11c0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] #0: ffffffff8c8e11c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338 #1: ffffffff8c897f30 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:895 [inline] #1: ffffffff8c897f30 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x660 mm/vmscan.c:1001 #2: ffff8880429940e0 (&type->s_umount_key#50){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline] #2: ffff8880429940e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79 stack backtrace: CPU: 1 PID: 109 Comm: kswapd0 Not tainted 6.3.0-rc7-syzkaller-00181-g8e41e0a57566 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747 fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] fsnotify_destroy_mark fs/notify/mark.c:496 [inline] fsnotify_destroy_marks+0x16a/0x4b0 fs/notify/mark.c:854 fsnotify_inoderemove include/linux/fsnotify.h:193 [inline] dentry_unlink_inode+0x3aa/0x460 fs/dcache.c:397 __dentry_kill+0x3c0/0x640 fs/dcache.c:607 shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282 super_cache_scan+0x33a/0x590 fs/super.c:104 do_shrink_slab+0x428/0xaa0 mm/vmscan.c:853 shrink_slab_memcg mm/vmscan.c:922 [inline] shrink_slab+0x388/0x660 mm/vmscan.c:1001 shrink_one+0x502/0x810 mm/vmscan.c:5343 shrink_many mm/vmscan.c:5394 [inline] lru_gen_shrink_node mm/vmscan.c:5511 [inline] shrink_node+0x2064/0x35f0 mm/vmscan.c:6459 kswapd_shrink_node mm/vmscan.c:7262 [inline] balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452 kswapd+0x677/0xd60 mm/vmscan.c:7712 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308