INFO: task kworker/u8:4:62 blocked for more than 143 seconds. Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:4 state:D stack:20664 pid:62 tgid:62 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:8) Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735 jfs_commit_inode+0x24a/0x590 fs/jfs/inode.c:102 jfs_write_inode+0x143/0x220 fs/jfs/inode.c:132 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047 wb_writeback+0x427/0xb80 fs/fs-writeback.c:2158 wb_check_background_flush fs/fs-writeback.c:2228 [inline] wb_do_writeback fs/fs-writeback.c:2316 [inline] wb_workfn+0xc4b/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 2 locks held by kworker/u8:2/35: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90000ab7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000ab7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 4 locks held by kworker/u8:4/62: #0: ffff8881416da948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff8881416da948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc9000213fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000213fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffff88807d4240e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562 #3: ffff888079228b00 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x24a/0x590 fs/jfs/inode.c:102 2 locks held by kworker/u8:5/188: 2 locks held by kworker/u8:6/1102: 5 locks held by kworker/u8:7/3551: 2 locks held by kworker/u8:8/3940: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc9000c977d00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000c977d00 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 2 locks held by getty/5571: #0: ffff888035cda0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 4 locks held by &¹úJ/9618: 2 locks held by syz.8.522/11206: #0: ffff88807d4240e0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807d4240e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff8881437e27d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8881437e27d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x26e/0xb50 fs/fs-writeback.c:2819 2 locks held by syz.1.524/11230: #0: ffff888024d3c0e0 (&type->s_umount_key#71/1){+.+.}-{4:4}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e7e3168 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5166 [inline] #1: ffffffff8e7e3168 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0xa55/0x1f20 kernel/workqueue.c:5720 1 lock held by syz.5.526/11240: 2 locks held by syz.6.527/11249: #0: ffff88807b4320e0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e7e3168 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5166 [inline] #1: ffffffff8e7e3168 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0xa55/0x1f20 kernel/workqueue.c:5720 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xff6/0x1040 kernel/hung_task.c:397 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 57 Comm: kworker/1:1 Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: 0x0 (mm_percpu_wq) RIP: 0010:pwq_dec_nr_in_flight+0x94e/0xd60 Code: 68 b4 5a 0a 48 8b 5c 24 40 48 39 eb 74 17 e8 59 9c 36 00 48 89 df e8 51 b4 5a 0a 48 89 ef e8 39 b1 5a 0a eb 05 e8 42 9c 36 00 <45> 89 f5 44 89 f0 49 8d 5c 87 1c 48 89 d8 48 c1 e8 03 42 0f b6 04 RSP: 0018:ffffc9000101fb20 EFLAGS: 00000093 RAX: ffffffff8168d0f4 RBX: ffff88801acaac68 RCX: ffff888020e89e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff88801acaac68 R08: ffffffff8168cf7e R09: 0000000000000000 R10: ffff88801faf9e10 R11: ffffed1003f5f3c5 R12: dffffc0000000000 R13: ffff8880b873dec0 R14: 0000000000000000 R15: ffff88801acaac00 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055db8c008950 CR3: 0000000051416000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work kernel/workqueue.c:3284 [inline] process_scheduled_works+0xf5d/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244