INFO: task syz.0.2235:12995 blocked for more than 143 seconds. Not tainted 6.6.101-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.2235 state:D stack:24176 pid:12995 ppid:11814 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833 __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:1059 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: 0033:0x7f863938ebe9 RSP: 002b:00007f863a251038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f86395b5fa0 RCX: 00007f863938ebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f86395b5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f86395b6038 R14: 00007f86395b5fa0 R15: 00007fff3fdbfd98 Showing all locks held in the system: 3 locks held by kworker/0:1/9: #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc900000e7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc900000e7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff8880b8e3c458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 3 locks held by kworker/1:1/27: #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: ffffc90000a2fd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90000a2fd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff88805b240240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26c/0x3170 drivers/net/netdevsim/fib.c:1491 1 lock held by khungtaskd/29: #0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:3/48: 3 locks held by kworker/u4:11/3473: #0: ffff88802cb1a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff88802cb1a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc9000c837d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000c837d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffffffff8dfbb888 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x14e0 net/ipv6/addrconf.c:4159 2 locks held by getty/5556: #0: ffff88814ded00a0 (&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/6500: #0: ffff8880219ef4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788 1 lock held by syz.0.2235/12995: #0: ffff8880219ef4c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1059 3 locks held by syz-executor/15874: #0: ffffffff8dfbb888 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline] #0: ffffffff8dfbb888 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472 #1: ffff888058fb93e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_open+0x227/0x420 drivers/net/wireguard/device.c:50 #2: ffffffff8cd35b78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #2: ffffffff8cd35b78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.6.101-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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: 3473 Comm: kworker/u4:11 Not tainted 6.6.101-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__lock_release kernel/locking/lockdep.c:5440 [inline] RIP: 0010:lock_release+0x248/0x8b0 kernel/locking/lockdep.c:5774 Code: e8 03 42 0f b6 04 28 84 c0 0f 85 91 04 00 00 41 83 3e 00 0f 85 be 03 00 00 4d 8d 74 24 20 4c 89 f3 48 c1 eb 03 42 0f b6 04 2b <84> c0 4c 8b 7c 24 08 0f 85 8d 04 00 00 41 8b 06 3d 00 00 20 00 72 RSP: 0018:ffffc9000c837760 EFLAGS: 00000802 RAX: 0000000000000000 RBX: 1ffff11005c5b8f4 RCX: 0000000000000001 RDX: 0000000000000004 RSI: ffff8880b8f39238 RDI: ffff88802e2dc780 RBP: ffffc9000c837870 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffff88802e2dc780 R13: dffffc0000000000 R14: ffff88802e2dc7a0 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd588984198 CR3: 0000000031f3c000 CR4: 00000000003506e0 Call Trace: local_lock_release include/linux/local_lock_internal.h:38 [inline] crng_make_state+0x32e/0x700 drivers/char/random.c:372 _get_random_bytes+0xd6/0x210 drivers/char/random.c:385 eth_random_addr include/linux/etherdevice.h:232 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:756 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x368/0xb00 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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