====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc4-syzkaller-00148-g50736169ecc8 #0 Not tainted ------------------------------------------------------ kswapd0/111 is trying to acquire lock: ffff88801f71e610 (sb_internal#2){.+.+}-{0:0}, at: btrfs_commit_inode_delayed_inode+0x110/0x330 fs/btrfs/delayed-inode.c:1275 but task is already holding lock: ffffffff8dd3ab20 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x166/0x1970 mm/vmscan.c:6798 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:3801 [inline] fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3815 might_alloc include/linux/sched/mm.h:334 [inline] slab_pre_alloc_hook mm/slub.c:3891 [inline] slab_alloc_node mm/slub.c:3981 [inline] kmalloc_trace_noprof+0x51/0x310 mm/slub.c:4148 kmalloc_noprof include/linux/slab.h:660 [inline] ulist_alloc+0x77/0x1c0 fs/btrfs/ulist.c:98 btrfs_quota_enable+0x342/0x1ef0 fs/btrfs/qgroup.c:1051 btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:3765 [inline] btrfs_ioctl+0x6af4/0x8290 fs/btrfs/ioctl.c:4762 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1007 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #3 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 btrfs_quota_enable+0x3a1/0x1ef0 fs/btrfs/qgroup.c:1086 btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:3765 [inline] btrfs_ioctl+0x6af4/0x8290 fs/btrfs/ioctl.c:4762 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1007 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x164/0xf40 fs/btrfs/transaction.c:315 start_transaction+0x427/0x1a70 fs/btrfs/transaction.c:700 btrfs_rebuild_free_space_tree+0xaa/0x480 fs/btrfs/free-space-tree.c:1323 btrfs_start_pre_rw_mount+0x218/0xf60 fs/btrfs/disk-io.c:2999 open_ctree+0x41ab/0x52e0 fs/btrfs/disk-io.c:3554 btrfs_fill_super fs/btrfs/super.c:946 [inline] btrfs_get_tree_super fs/btrfs/super.c:1863 [inline] btrfs_get_tree+0x11e9/0x1b90 fs/btrfs/super.c:2089 vfs_get_tree+0x8f/0x380 fs/super.c:1780 fc_mount+0x16/0xc0 fs/namespace.c:1125 btrfs_get_tree_subvol fs/btrfs/super.c:2052 [inline] btrfs_get_tree+0xa53/0x1b90 fs/btrfs/super.c:2090 vfs_get_tree+0x8f/0x380 fs/super.c:1780 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (btrfs_trans_num_writers){++++}-{0:0}: join_transaction+0x148/0xf40 fs/btrfs/transaction.c:314 start_transaction+0x427/0x1a70 fs/btrfs/transaction.c:700 btrfs_rebuild_free_space_tree+0xaa/0x480 fs/btrfs/free-space-tree.c:1323 btrfs_start_pre_rw_mount+0x218/0xf60 fs/btrfs/disk-io.c:2999 open_ctree+0x41ab/0x52e0 fs/btrfs/disk-io.c:3554 btrfs_fill_super fs/btrfs/super.c:946 [inline] btrfs_get_tree_super fs/btrfs/super.c:1863 [inline] btrfs_get_tree+0x11e9/0x1b90 fs/btrfs/super.c:2089 vfs_get_tree+0x8f/0x380 fs/super.c:1780 fc_mount+0x16/0xc0 fs/namespace.c:1125 btrfs_get_tree_subvol fs/btrfs/super.c:2052 [inline] btrfs_get_tree+0xa53/0x1b90 fs/btrfs/super.c:2090 vfs_get_tree+0x8f/0x380 fs/super.c:1780 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (sb_internal#2){.+.+}-{0:0}: 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+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1655 [inline] sb_start_intwrite include/linux/fs.h:1838 [inline] start_transaction+0xbc1/0x1a70 fs/btrfs/transaction.c:694 btrfs_commit_inode_delayed_inode+0x110/0x330 fs/btrfs/delayed-inode.c:1275 btrfs_evict_inode+0x960/0xe80 fs/btrfs/inode.c:5291 evict+0x2ed/0x6c0 fs/inode.c:667 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 dput.part.0+0x4b1/0x9b0 fs/dcache.c:845 dput+0x1f/0x30 fs/dcache.c:835 ovl_stack_put+0x60/0x90 fs/overlayfs/util.c:132 ovl_destroy_inode+0xc6/0x190 fs/overlayfs/super.c:182 destroy_inode+0xc4/0x1b0 fs/inode.c:311 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __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+0x44f/0x11c0 mm/shrinker.c:435 shrink_slab_memcg mm/shrinker.c:548 [inline] shrink_slab+0xa87/0x1310 mm/shrinker.c:626 shrink_one+0x493/0x7c0 mm/vmscan.c:4790 shrink_many mm/vmscan.c:4851 [inline] lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4951 shrink_node mm/vmscan.c:5910 [inline] kswapd_shrink_node mm/vmscan.c:6720 [inline] balance_pgdat+0x1105/0x1970 mm/vmscan.c:6911 kswapd+0x5ea/0xbf0 mm/vmscan.c:7180 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Chain exists of: sb_internal#2 --> &fs_info->qgroup_ioctl_lock --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&fs_info->qgroup_ioctl_lock); lock(fs_reclaim); rlock(sb_internal#2); *** DEADLOCK *** 2 locks held by kswapd0/111: #0: ffffffff8dd3ab20 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x166/0x1970 mm/vmscan.c:6798 #1: ffff888000a4a0e0 (&type->s_umount_key#57){++++}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline] #1: ffff888000a4a0e0 (&type->s_umount_key#57){++++}-{3:3}, at: super_cache_scan+0x96/0x550 fs/super.c:196 stack backtrace: CPU: 3 PID: 111 Comm: kswapd0 Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8 #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+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/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+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1655 [inline] sb_start_intwrite include/linux/fs.h:1838 [inline] start_transaction+0xbc1/0x1a70 fs/btrfs/transaction.c:694 btrfs_commit_inode_delayed_inode+0x110/0x330 fs/btrfs/delayed-inode.c:1275 btrfs_evict_inode+0x960/0xe80 fs/btrfs/inode.c:5291 evict+0x2ed/0x6c0 fs/inode.c:667 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 dput.part.0+0x4b1/0x9b0 fs/dcache.c:845 dput+0x1f/0x30 fs/dcache.c:835 ovl_stack_put+0x60/0x90 fs/overlayfs/util.c:132 ovl_destroy_inode+0xc6/0x190 fs/overlayfs/super.c:182 destroy_inode+0xc4/0x1b0 fs/inode.c:311 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __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+0x44f/0x11c0 mm/shrinker.c:435 shrink_slab_memcg mm/shrinker.c:548 [inline] shrink_slab+0xa87/0x1310 mm/shrinker.c:626 shrink_one+0x493/0x7c0 mm/vmscan.c:4790 shrink_many mm/vmscan.c:4851 [inline] lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4951 shrink_node mm/vmscan.c:5910 [inline] kswapd_shrink_node mm/vmscan.c:6720 [inline] balance_pgdat+0x1105/0x1970 mm/vmscan.c:6911 kswapd+0x5ea/0xbf0 mm/vmscan.c:7180 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244