INFO: task syz-executor.4:25347 blocked for more than 143 seconds. Not tainted 6.12.0-next-20241122-syzkaller-12501-gcfba9f07a1d6 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:25912 pid:25347 tgid:25343 ppid:6148 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common kernel/sched/completion.c:127 [inline] wait_for_completion+0x355/0x620 kernel/sched/completion.c:148 __flush_workqueue+0x573/0x1280 kernel/workqueue.c:3987 nbd_start_device_ioctl drivers/block/nbd.c:1478 [inline] __nbd_ioctl drivers/block/nbd.c:1539 [inline] nbd_ioctl+0xbd1/0xf40 drivers/block/nbd.c:1579 blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x455ae9 RSP: 002b:00007fbc3a6210d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bfa8 RCX: 0000000000455ae9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00000000004a166d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004a0800 R13: 000000000000006e R14: 000000000055bfa8 R15: 00007ffc5139ffc8 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 getty/5580: #0: ffff8880311150a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fc62f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 2 locks held by kworker/u9:9/6167: #0: ffff888025c7e948 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff888025c7e948 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc90004a47d00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90004a47d00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 2 locks held by udevd/25575: #0: ffff888025ce94c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1087 #1: ffff8880b8628948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x41d/0x7a0 kernel/sched/psi.c:987 1 lock held by syz-executor290/31083: #0: ffff888025c65998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 3 locks held by syz-executor290/31084: #0: ffff888025c65998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff8880256058b0 (&q->q_usage_counter(io)#50){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 #2: ffff8880256058e8 (&q->q_usage_counter(queue)#34){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 1 lock held by syz-executor290/31081: #0: ffff888025c74198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 3 locks held by syz-executor290/31082: #0: ffff888025c74198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff888025606278 (&q->q_usage_counter(io)#51){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 #2: ffff8880256062b0 (&q->q_usage_counter(queue)#35){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 3 locks held by syz-executor290/31071: #0: ffff888025da1198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff888025607608 (&q->q_usage_counter(io)#54){+.+.}-{0:0}, at: nbd_set_size+0xe0/0x8f0 drivers/block/nbd.c:387 #2: ffff888025607640 (&q->q_usage_counter(queue)#38){+.+.}-{0:0}, at: nbd_set_size+0xe0/0x8f0 drivers/block/nbd.c:387 3 locks held by syz-executor290/31078: #0: ffff888143f90198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff888025604ee8 (&q->q_usage_counter(io)#49){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 #2: ffff888025604f20 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 1 lock held by syz-executor290/31080: #0: ffff888143f90198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 1 lock held by syz-executor290/31085: #0: ffff888143f90198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 1 lock held by syz-executor290/31086: #0: ffff888143f90198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 3 locks held by syz-executor290/31090: #0: ffff888025c7a998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff888025606c40 (&q->q_usage_counter(io)#53){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 #2: ffff888025606c78 (&q->q_usage_counter(queue)#37){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 1 lock held by syz-executor290/31091: #0: ffff888025c7a998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 1 lock held by syz-executor290/31096: #0: ffff888025c7a998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 3 locks held by syz-executor290/31089: #0: ffff888025ce2198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 #1: ffff888143350a70 (&q->q_usage_counter(io)#52){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 #2: ffff888143350aa8 (&q->q_usage_counter(queue)#36){+.+.}-{0:0}, at: nbd_add_socket+0x1a5/0x8f0 drivers/block/nbd.c:1189 1 lock held by syz-executor290/31092: #0: ffff888025ce2198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 1 lock held by syz-executor290/31093: #0: ffff888025ce2198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 1 lock held by syz-executor290/31094: #0: ffff888025ce2198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-next-20241122-syzkaller-12501-gcfba9f07a1d6 #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+0xffb/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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5847 Comm: kworker/0:4 Not tainted 6.12.0-next-20241122-syzkaller-12501-gcfba9f07a1d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: rcu_gp process_srcu RIP: 0010:delay_tsc+0x5c/0xe0 arch/x86/lib/delay.c:79 Code: 90 48 89 d5 48 c1 e5 20 48 09 c5 48 29 dd 4c 39 f5 73 67 bf 01 00 00 00 e8 e1 69 a6 f5 65 8b 05 c2 bc 3c 74 85 c0 74 2f f3 90 01 00 00 00 e8 2a 68 a6 f5 e8 15 53 01 00 41 39 c7 75 20 0f 01 RSP: 0018:ffffc90004177a28 EFLAGS: 00000286 RAX: 0000000080000000 RBX: 000001138b13df74 RCX: 0000000000000001 RDX: 0000000000000113 RSI: ffffffff8c5e8900 RDI: 0000000000000001 RBP: 000000000000153e R08: ffffe8ffffd0d3cf R09: 1ffffd1ffffa1a79 R10: dffffc0000000000 R11: ffffffff8bc718f0 R12: ffff888143fc6308 R13: 0000000000000002 R14: 0000000000002afa R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc74524be08 CR3: 0000000066f6e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: udelay include/asm-generic/delay.h:64 [inline] try_check_zero+0x43b/0x4a0 kernel/rcu/srcutree.c:1112 srcu_advance_state kernel/rcu/srcutree.c:1742 [inline] process_srcu+0x242/0x12e0 kernel/rcu/srcutree.c:1851 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 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