INFO: task kworker/u8:5:1010 blocked for more than 143 seconds. Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:5 state:D stack:21816 pid:1010 tgid:1010 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:4) Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:132 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x6f1/0xff0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 3 locks held by kworker/u8:1/13: #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90000127bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000127bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by khungtaskd/31: #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 4 locks held by kworker/u8:5/1010: #0: ffff88801f6cc148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801f6cc148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000384fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000384fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff888025fea0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff8880559cf068 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102 7 locks held by kworker/u8:10/3522: #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000bca7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000bca7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4f0850 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:662 #3: ffff888143eda0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #3: ffff888143eda0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff888143eda0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506 #4: ffff8881463bd250 (&devlink->lock_key#13){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff8881463bd250 (&devlink->lock_key#13){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff8881463bd250 (&devlink->lock_key#13){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506 #5: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xdb/0x670 drivers/net/netdevsim/netdev.c:1064 #6: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #6: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998 1 lock held by udevd/5193: 1 lock held by dhcpcd/5488: #0: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x323/0x1b50 net/ipv4/devinet.c:1121 2 locks held by getty/5586: #0: ffff888034c220a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bc2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 4 locks held by syz.4.21/6056: 3 locks held by kworker/0:7/7244: #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90003ccfbc0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90003ccfbc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 2 locks held by syz.3.153/7335: #0: ffff888025fea0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff888025fea0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 #1: ffff8881427d87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8881427d87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz-executor/7338: #0: ffffffff8e87d9c8 (bio_slab_lock){+.+.}-{4:4}, at: bio_put_slab block/bio.c:140 [inline] #0: ffffffff8e87d9c8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690 block/bio.c:1758 #1: ffffffff8e144840 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3786 2 locks held by syz.2.180/7357: #0: ffff888025fea0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff888025fea0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 #1: ffff8881427d87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8881427d87d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz-executor/7906: #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4054 2 locks held by syz-executor/7972: #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8ec91bc0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f4fd448 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4054 1 lock held by syz.0.253/8107: #0: ffffffff8e87d9c8 (bio_slab_lock){+.+.}-{4:4}, at: bio_find_or_create_slab block/bio.c:122 [inline] #0: ffffffff8e87d9c8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_init+0x241/0x790 block/bio.c:1799 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5182 Comm: klogd Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235 Code: 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 8e 64 a2 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 RSP: 0018:ffffc90003287878 EFLAGS: 00000293 RAX: ffffffff8b5c3c45 RBX: ffffffff8b8b8280 RCX: ffff88807ee6bc00 RDX: 0000000000000000 RSI: ffffffff8b8b8280 RDI: ffffc90003287ad1 RBP: ffffc90003287970 R08: ffffc90003287757 R09: 0000000000000000 R10: ffffc90003287740 R11: fffff52000650eeb R12: 1ffff92000650f18 R13: dffffc0000000000 R14: ffffc90003287ad1 R15: ffffc900032878e0 FS: 00007f90205b2c80(0000) GS:ffff888125d84000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f145ef80ab8 CR3: 0000000033498000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sprintf+0x95/0x120 lib/vsprintf.c:3032 print_caller kernel/printk/printk.c:1392 [inline] info_print_prefix+0x1f3/0x310 kernel/printk/printk.c:1409 record_print_text+0x154/0x430 kernel/printk/printk.c:1456 syslog_print+0x34f/0x590 kernel/printk/printk.c:1667 do_syslog+0x544/0x760 kernel/printk/printk.c:1785 __do_sys_syslog kernel/printk/printk.c:1877 [inline] __se_sys_syslog kernel/printk/printk.c:1875 [inline] __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1875 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f902077ca37 Code: 73 01 c3 48 8b 0d c1 f3 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 f3 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe77c12648 EFLAGS: 00000206 ORIG_RAX: 0000000000000067 RAX: ffffffffffffffda RBX: 00007f902091c490 RCX: 00007f902077ca37 RDX: 00000000000003ff RSI: 00007f902091c490 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000206 R12: 00007f902091c490 R13: 00007f90208f9dfe R14: 00007f902091c87d R15: 00007f902091c87d