INFO: task syz.3.111:6618 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.111 state:D stack:24872 pid:6618 ppid:5774 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747 sync_bdevs+0x1af/0x330 block/bdev.c:1076 ksys_sync+0xba/0x150 fs/sync.c:105 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f83f7d8f749 RSP: 002b:00007f83f8c5f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f83f7fe5fa0 RCX: 00007f83f7d8f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f83f7fe5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f83f7fe6038 R14: 00007f83f7fe5fa0 R15: 00007ffddd025a08 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5528: #0: ffff88803116a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217 1 lock held by udevd/5770: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805 5 locks held by kworker/1:4/5809: #0: ffff888019e95538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888019e95538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc9000480fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000480fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff8880251cd190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff8880251cd190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5861 #3: ffff888079986190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #3: ffff888079986190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 #4: ffff88803016d160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #4: ffff88803016d160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 3 locks held by kworker/0:4/5830: #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc9000495fd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000495fd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff88802ec62240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26c/0x3170 drivers/net/netdevsim/fib.c:1491 3 locks held by kworker/u4:20/6292: 1 lock held by syz.3.111/6618: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.5.191/7138: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.5.191/7172: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.5.191/7173: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.5.191/7174: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.5.191/7175: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.6.398/8089: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz.6.398/8090: #0: ffff8881413e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 2 locks held by syz.8.485/8476: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf41/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5754 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20 arch/x86/include/asm/idtentry.h:687 Code: c6 5c e7 ff e9 c1 04 00 00 90 f3 0f 1e fa 0f 01 ca fc 6a ff e8 c1 03 00 00 48 89 c4 48 89 e7 e8 e6 5b e7 ff e9 a1 04 00 00 90 0f 1e fa 0f 01 ca fc 6a ff e8 a1 03 00 00 48 89 c4 48 89 e7 e8 RSP: 0018:ffffc90003c07d48 EFLAGS: 00000046 RAX: ffffc90003c07e00 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003c07ec0 R08: ffffc90003c07e1f R09: 0000000000000000 R10: ffffc90003c07e00 R11: fffff52000780fc4 R12: ffff88802275bc00 R13: ffff88802275d158 R14: ffffc90003c07e00 R15: 0000000000000000 FS: 000055559064d500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c36e092 CR3: 000000003161f000 CR4: 00000000003506e0 Call Trace: RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x0/0x80 kernel/kcov.c:321 Code: c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1e fa 48 8b 04 24 65 48 8b 0d b0 20 7e 7e 65 8b 15 b1 20 7e RSP: 0018:ffffc90003c07d78 EFLAGS: 00000246 rseq_get_rseq_cs kernel/rseq.c:188 [inline] rseq_ip_fixup kernel/rseq.c:303 [inline] __rseq_handle_notify_resume+0x336/0x1170 kernel/rseq.c:351 rseq_handle_notify_resume include/linux/sched.h:2364 [inline] resume_user_mode_work include/linux/resume_user_mode.h:61 [inline] exit_to_user_mode_loop+0xbc/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd97ddc1fc3 Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d 9e 95 1f 00 00 74 14 b8 e6 00 00 00 0f 05 d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10 RSP: 002b:00007ffc9251dfd8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fd97ddc1fc3 RDX: 00007ffc9251dff0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000110 R09: 0000000000745d1e R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffc9251e440 R13: 0000000000000004 R14: 00007ffc9251e02c R15: 00007ffc9251e0c0