INFO: task syz-executor.3:14197 blocked for more than 143 seconds. Not tainted 5.6.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28672 14197 7240 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_timeout+0x6db/0xba0 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x26a/0x3c0 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x7ae/0xb7c drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x25b/0x660 block/ioctl.c:717 block_ioctl+0xe9/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: Bad RIP value. RSP: 002b:00007f968fe4bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f968fe4c6d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000400 R14: 00000000004c69ca R15: 000000000076bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1131: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 2 locks held by kworker/u5:0/1617: #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff888087289928 ((wq_completion)knbd3-recv){+.+.}, at: process_one_work+0x82a/0x1690 kernel/workqueue.c:2237 #1: ffffc90005527dd0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x85e/0x1690 kernel/workqueue.c:2241 1 lock held by in:imklog/6670: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1131 Comm: khungtaskd Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4102 Comm: systemd-journal Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1a/0x50 kernel/kcov.c:187 Code: c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 c0 1e 02 00 65 8b 15 58 f9 8f 7e 81 e2 00 01 1f 00 48 8b 34 24 <75> 2b 8b 90 80 13 00 00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 RSP: 0018:ffffc90001477ca0 EFLAGS: 00000246 RAX: ffff8880a76a0300 RBX: 000000007fff0000 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffffff81728d93 RDI: ffffffff880f3ca0 RBP: ffff8880a7210d00 R08: ffff8880a76a0300 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 000000007fff0000 R14: ffffc90001477e70 R15: 000000007fff0000 FS: 00007f387c8118c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f38772ec000 CR3: 00000000a8fca000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_static_branch arch/x86/include/asm/jump_label.h:25 [inline] seccomp_run_filters kernel/seccomp.c:273 [inline] __seccomp_filter+0x123/0x13b0 kernel/seccomp.c:815 __secure_computing+0xfc/0x360 kernel/seccomp.c:948 syscall_trace_enter+0x2a3/0xd10 arch/x86/entry/common.c:118 do_syscall_64+0x504/0x7d0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f387bacd9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007fff205502c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fff205532f0 RCX: 00007f387bacd9c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055e23c3009a3 RBP: 00007fff20550410 R08: 000055e23c2f63e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055e23cb698c0 R15: 00007fff20550900