====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc5-syzkaller-00029-g39133352cbed #0 Not tainted ------------------------------------------------------ kswapd0/109 is trying to acquire lock: ffff888029dc0130 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] ffff888029dc0130 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_destroy_mark fs/notify/mark.c:496 [inline] ffff888029dc0130 (&group->mark_mutex){+.+.}-{3:3}, at: fsnotify_destroy_marks+0x149/0x4a0 fs/notify/mark.c:818 but task is already holding lock: ffffffff8d720500 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6771 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:3692 [inline] fs_reclaim_acquire+0x104/0x150 mm/page_alloc.c:3706 might_alloc include/linux/sched/mm.h:303 [inline] slab_pre_alloc_hook mm/slub.c:3761 [inline] slab_alloc_node mm/slub.c:3842 [inline] kmem_cache_alloc+0x4f/0x320 mm/slub.c:3867 inotify_new_watch fs/notify/inotify/inotify_user.c:599 [inline] inotify_update_watch+0x527/0xc10 fs/notify/inotify/inotify_user.c:647 __do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:786 [inline] __se_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:729 [inline] __x64_sys_inotify_add_watch+0x2e9/0x380 fs/notify/inotify/inotify_user.c:729 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6f/0x77 -> #0 (&group->mark_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x244f/0x3b40 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:752 fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] fsnotify_destroy_mark fs/notify/mark.c:496 [inline] fsnotify_destroy_marks+0x149/0x4a0 fs/notify/mark.c:818 fsnotify_inoderemove include/linux/fsnotify.h:233 [inline] dentry_unlink_inode+0x38f/0x440 fs/dcache.c:396 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 shrink_kill fs/dcache.c:1048 [inline] shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156 super_cache_scan+0x32a/0x550 fs/super.c:221 do_shrink_slab+0x426/0x1120 mm/shrinker.c:435 shrink_slab_memcg mm/shrinker.c:548 [inline] shrink_slab+0xa87/0x1310 mm/shrinker.c:626 shrink_one+0x493/0x7b0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x21d0/0x3790 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat+0x9d2/0x1a90 mm/vmscan.c:6883 kswapd+0x5be/0xc00 mm/vmscan.c:7143 kthread+0x2c6/0x3b0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 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 *** 2 locks held by kswapd0/109: #0: ffffffff8d720500 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6771 #1: ffff88801d5600e0 (&type->s_umount_key#52){++++}-{3:3}, at: super_trylock_shared fs/super.c:566 [inline] #1: ffff88801d5600e0 (&type->s_umount_key#52){++++}-{3:3}, at: super_cache_scan+0x96/0x550 fs/super.c:196 stack backtrace: CPU: 0 PID: 109 Comm: kswapd0 Not tainted 6.8.0-rc5-syzkaller-00029-g39133352cbed #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x31b/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x244f/0x3b40 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:752 fsnotify_group_lock include/linux/fsnotify_backend.h:266 [inline] fsnotify_destroy_mark fs/notify/mark.c:496 [inline] fsnotify_destroy_marks+0x149/0x4a0 fs/notify/mark.c:818 fsnotify_inoderemove include/linux/fsnotify.h:233 [inline] dentry_unlink_inode+0x38f/0x440 fs/dcache.c:396 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 shrink_kill fs/dcache.c:1048 [inline] shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156 super_cache_scan+0x32a/0x550 fs/super.c:221 do_shrink_slab+0x426/0x1120 mm/shrinker.c:435 shrink_slab_memcg mm/shrinker.c:548 [inline] shrink_slab+0xa87/0x1310 mm/shrinker.c:626 shrink_one+0x493/0x7b0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x21d0/0x3790 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat+0x9d2/0x1a90 mm/vmscan.c:6883 kswapd+0x5be/0xc00 mm/vmscan.c:7143 kthread+0x2c6/0x3b0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242