====================================================== WARNING: possible circular locking dependency detected 6.14.0-syzkaller-03565-gf6e0150b2003 #0 Not tainted ------------------------------------------------------ kswapd0/81 is trying to acquire lock: ffff8880449be7d8 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:1037 [inline] ffff8880449be7d8 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1729 [inline] ffff8880449be7d8 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_icwalk_ag+0x1219/0x1ad0 fs/xfs/xfs_icache.c:1811 but task is already holding lock: ffffffff8ec3c500 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6886 [inline] ffffffff8ec3c500 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xba1/0x3b40 mm/vmscan.c:7264 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __fs_reclaim_acquire mm/page_alloc.c:3853 [inline] fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4089 [inline] slab_alloc_node mm/slub.c:4167 [inline] kmem_cache_alloc_node_noprof+0x4e/0x3b0 mm/slub.c:4239 __alloc_skb+0x1c2/0x480 net/core/skbuff.c:596 alloc_skb include/linux/skbuff.h:1331 [inline] alloc_uevent_skb+0x74/0x230 lib/kobject_uevent.c:289 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast+0x2fd/0x580 lib/kobject_uevent.c:410 kobject_uevent_env+0x57d/0x8e0 lib/kobject_uevent.c:608 kobject_synth_uevent+0x4f4/0xaf0 lib/kobject_uevent.c:207 bus_uevent_store+0x116/0x170 drivers/base/bus.c:832 kernfs_fop_write_iter+0x3a5/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x70f/0xd10 fs/read_write.c:684 ksys_write+0x19d/0x2d0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (uevent_sock_mutex){+.+.}-{4:4}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:587 [inline] __mutex_lock+0x1bf/0x1000 kernel/locking/mutex.c:732 uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline] kobject_uevent_net_broadcast+0x280/0x580 lib/kobject_uevent.c:410 kobject_uevent_env+0x57d/0x8e0 lib/kobject_uevent.c:608 loop_set_size drivers/block/loop.c:235 [inline] loop_set_status+0x4f8/0x800 drivers/block/loop.c:1292 lo_ioctl+0xcef/0x2870 drivers/block/loop.c:-1 blkdev_ioctl+0x5df/0x710 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&q->q_usage_counter(io)#17){++++}-{0:0}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 bio_queue_enter block/blk.h:78 [inline] blk_mq_submit_bio+0x14e3/0x25e0 block/blk-mq.c:3091 __submit_bio+0x1d2/0x6d0 block/blk-core.c:628 __submit_bio_noacct_mq block/blk-core.c:715 [inline] submit_bio_noacct_nocheck+0x4d5/0xe30 block/blk-core.c:744 xlog_state_release_iclog+0x41d/0x7b0 fs/xfs/xfs_log.c:567 xlog_force_iclog fs/xfs/xfs_log.c:802 [inline] xlog_force_and_check_iclog fs/xfs/xfs_log.c:2864 [inline] xfs_log_force+0x61c/0x970 fs/xfs/xfs_log.c:2941 xfs_qm_dqflush+0x9ae/0x1130 fs/xfs/xfs_dquot.c:1463 xfs_qm_flush_one+0x297/0x490 fs/xfs/xfs_qm.c:1537 xfs_qm_dquot_walk+0x234/0x4b0 fs/xfs/xfs_qm.c:90 xfs_qm_quotacheck+0x3ac/0x6f0 fs/xfs/xfs_qm.c:1619 xfs_qm_mount_quotas+0x38f/0x680 fs/xfs/xfs_qm.c:1739 xfs_mountfs+0x1f41/0x2510 fs/xfs/xfs_mount.c:1041 xfs_fs_fill_super+0x1223/0x1550 fs/xfs/xfs_super.c:1817 get_tree_bdev_flags+0x490/0x5c0 fs/super.c:1636 vfs_get_tree+0x90/0x2b0 fs/super.c:1759 do_new_mount+0x2cf/0xb70 fs/namespace.c:3878 do_mount fs/namespace.c:4218 [inline] __do_sys_mount fs/namespace.c:4429 [inline] __se_sys_mount+0x38c/0x400 fs/namespace.c:4406 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&xfs_dquot_group_class){+.+.}-{4:4}: reacquire_held_locks+0x12a/0x1e0 kernel/locking/lockdep.c:5383 __lock_release kernel/locking/lockdep.c:5572 [inline] lock_release+0x27a/0x3e0 kernel/locking/lockdep.c:5887 __mutex_unlock_slowpath+0xee/0x800 kernel/locking/mutex.c:893 xfs_qm_dqget_cache_lookup+0x340/0x8b0 fs/xfs/xfs_dquot.c:829 xfs_qm_dqget_inode+0x30a/0xb40 fs/xfs/xfs_dquot.c:1022 xfs_qm_dqattach_one+0x189/0x620 fs/xfs/xfs_qm.c:320 xfs_qm_dqattach_locked+0x446/0x530 fs/xfs/xfs_qm.c:382 xfs_qm_vop_dqalloc+0x3ff/0xf00 fs/xfs/xfs_qm.c:1978 xfs_icreate_dqalloc+0x311/0x360 fs/xfs/xfs_inode.c:643 xfs_create+0x4d7/0x1060 fs/xfs/xfs_inode.c:678 xfs_generic_create+0x5d9/0xf50 fs/xfs/xfs_iops.c:215 lookup_open fs/namei.c:3666 [inline] open_last_lookups fs/namei.c:3765 [inline] path_openat+0x194b/0x35d0 fs/namei.c:4001 do_filp_open+0x284/0x4e0 fs/namei.c:4031 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_open fs/open.c:1452 [inline] __se_sys_open fs/open.c:1448 [inline] __x64_sys_open+0x226/0x280 fs/open.c:1448 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&xfs_dir_ilock_class){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693 xfs_reclaim_inode fs/xfs/xfs_icache.c:1037 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1729 [inline] xfs_icwalk_ag+0x1219/0x1ad0 fs/xfs/xfs_icache.c:1811 xfs_icwalk fs/xfs/xfs_icache.c:1859 [inline] xfs_reclaim_inodes_nr+0x2b2/0x390 fs/xfs/xfs_icache.c:1103 super_cache_scan+0x46a/0x510 fs/super.c:227 do_shrink_slab+0x715/0x1140 mm/shrinker.c:437 shrink_slab+0x1097/0x14e0 mm/shrinker.c:664 shrink_one+0x43b/0x850 mm/vmscan.c:4868 shrink_many mm/vmscan.c:4929 [inline] lru_gen_shrink_node mm/vmscan.c:5007 [inline] shrink_node+0x37c3/0x3e30 mm/vmscan.c:5978 kswapd_shrink_node mm/vmscan.c:6807 [inline] balance_pgdat mm/vmscan.c:6999 [inline] kswapd+0x2110/0x3b40 mm/vmscan.c:7264 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 other info that might help us debug this: Chain exists of: &xfs_dir_ilock_class --> uevent_sock_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(uevent_sock_mutex); lock(fs_reclaim); lock(&xfs_dir_ilock_class); *** DEADLOCK *** 2 locks held by kswapd0/81: #0: ffffffff8ec3c500 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6886 [inline] #0: ffffffff8ec3c500 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xba1/0x3b40 mm/vmscan.c:7264 #1: ffff8880530d20e0 (&type->s_umount_key#49){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:562 [inline] #1: ffff8880530d20e0 (&type->s_umount_key#49){.+.+}-{4:4}, at: super_cache_scan+0x94/0x510 fs/super.c:196 stack backtrace: CPU: 0 UID: 0 PID: 81 Comm: kswapd0 Not tainted 6.14.0-syzkaller-03565-gf6e0150b2003 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211 check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693 xfs_reclaim_inode fs/xfs/xfs_icache.c:1037 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1729 [inline] xfs_icwalk_ag+0x1219/0x1ad0 fs/xfs/xfs_icache.c:1811 xfs_icwalk fs/xfs/xfs_icache.c:1859 [inline] xfs_reclaim_inodes_nr+0x2b2/0x390 fs/xfs/xfs_icache.c:1103 super_cache_scan+0x46a/0x510 fs/super.c:227 do_shrink_slab+0x715/0x1140 mm/shrinker.c:437 shrink_slab+0x1097/0x14e0 mm/shrinker.c:664 shrink_one+0x43b/0x850 mm/vmscan.c:4868 shrink_many mm/vmscan.c:4929 [inline] lru_gen_shrink_node mm/vmscan.c:5007 [inline] shrink_node+0x37c3/0x3e30 mm/vmscan.c:5978 kswapd_shrink_node mm/vmscan.c:6807 [inline] balance_pgdat mm/vmscan.c:6999 [inline] kswapd+0x2110/0x3b40 mm/vmscan.c:7264 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245