INFO: task kworker/0:0H:11 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0H state:D stack:26568 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: kblockd blk_mq_requeue_work Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 wait_for_reconnect drivers/block/nbd.c:1107 [inline] nbd_handle_cmd drivers/block/nbd.c:1149 [inline] nbd_queue_rq+0x889/0x1150 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2356 blk_mq_run_hw_queues+0x268/0x3f0 block/blk-mq.c:2404 blk_mq_requeue_work+0x703/0x760 block/blk-mq.c:1571 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 4 locks held by kworker/0:0H/11: #0: ffff88801ea90540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88801ea90540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc90000107c40 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90000107c40 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #2: ffff888027710d18 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline] #2: ffff888027710d18 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline] #2: ffff888027710d18 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2355 #3: ffff888027d953b8 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc1/0x1150 drivers/block/nbd.c:1199 1 lock held by khungtaskd/30: #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by klogd/4981: #0: ffff8880b863b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:667 2 locks held by getty/5377: #0: ffff888036e2e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 1 lock held by udevd/11559: #0: ffff888027d1b350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:948 7 locks held by syz-executor/15927: #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888075b49080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff88802aee2128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #4: ffff88802aee2128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline] #4: ffff88802aee2128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369 #5: ffff88802aee6258 (&devlink->lock_key#3){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1799 #6: ffffffff8eb5fe38 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857 4 locks held by syz-executor/18636: #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff8880585c0c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/20385: #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888034808450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888037ee6480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029baf1e8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 1 lock held by syz.2.4292/21092: #0: ffff888020347140 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #0: ffff888020347140 (&dev->mutex){....}-{4:4}, at: nfc_unregister_rfkill+0x63/0x280 net/nfc/core.c:1166 4 locks held by syz.2.4292/21093: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 #2: ffff888020347140 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #2: ffff888020347140 (&dev->mutex){....}-{4:4}, at: nfc_dev_up+0x3c/0x350 net/nfc/core.c:95 #3: ffff888056166348 (&ndev->req_lock){+.+.}-{4:4}, at: nci_open_device net/nfc/nci/core.c:478 [inline] #3: ffff888056166348 (&ndev->req_lock){+.+.}-{4:4}, at: nci_dev_up+0xa3/0xdc0 net/nfc/nci/core.c:643 2 locks held by syz.2.4292/21101: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.2.4292/21109: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.2.4292/21114: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.4.4295/21106: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.1.4297/21111: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.0.4305/21152: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.0.4305/21153: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.0.4305/21154: #0: ffffffff9009c868 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff9009c6a0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 7c 80 02 e9 13 05 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 5a 1a 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e807de0 EFLAGS: 00000242 RAX: 00000000001f9729 RBX: ffffffff819ab450 RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8e22a5a0 RDI: ffffffff8c4bd380 RBP: ffffffff8e807eb8 R08: ffff8880b86338db R09: 1ffff110170c671b R10: dffffc0000000000 R11: ffffed10170c671c R12: 0000000000000000 R13: 1ffffffff1d11de8 R14: 1ffffffff1d00fc4 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888124f58000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c28c8c9 CR3: 000000007544a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x2e0/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 rest_init+0x2de/0x300 init/main.c:717 start_kernel+0x392/0x3e0 init/main.c:1175 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x157