INFO: task syz-executor.3:21906 blocked for more than 143 seconds. Not tainted 5.8.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28760 21906 7129 0x00004004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2832 nbd_start_device_ioctl drivers/block/nbd.c:1327 [inline] __nbd_ioctl drivers/block/nbd.c:1402 [inline] nbd_ioctl+0x7ac/0xb77 drivers/block/nbd.c:1442 __blkdev_driver_ioctl block/ioctl.c:224 [inline] blkdev_ioctl+0x255/0x6c0 block/ioctl.c:620 block_ioctl+0xf9/0x140 fs/block_dev.c:1988 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cba9 Code: Bad RIP value. RSP: 002b:00007fe3473c9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004eac40 RCX: 000000000045cba9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000042c R14: 00000000004c6fde R15: 00007fe3473ca6d4 Showing all locks held in the system: 1 lock held by khungtaskd/1151: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6517: #0: ffff88809ab81870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by kworker/u5:1/5149: #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880a8649938 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90001a1fda8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1151 Comm: khungtaskd Not tainted 5.8.0-rc5-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3892 Comm: systemd-journal Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:build_open_flags+0x2/0x650 fs/open.c:1006 Code: e7 e8 12 47 f6 ff e9 75 ff ff ff e8 08 47 f6 ff eb af e8 01 47 f6 ff eb 87 31 ed e9 44 ff ff ff 0f 1f 84 00 00 00 00 00 41 57 <41> 56 41 55 49 89 fd 41 54 55 48 89 f5 53 48 83 ec 08 e8 47 e2 b6 RSP: 0018:ffffc90001477db8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000088042 RCX: ffffffff81bce8c1 RDX: ffff8880934f0100 RSI: ffffc90001477df8 RDI: ffffc90001477eb0 RBP: 1ffff9200028efbb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90001477eb0 R13: 000055a715c18160 R14: 00000000ffffff9c R15: dffffc0000000000 FS: 00007f7b2a83b8c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7b27703020 CR3: 000000009367b000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_sys_openat2+0x86/0x3b0 fs/open.c:1167 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f7b29dcb840 Code: Bad RIP value. RSP: 002b:00007fffb6f9f9b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fffb6f9fcc0 RCX: 00007f7b29dcb840 RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 000055a715c18160 RBP: 000000000000000d R08: 000000000000ffc0 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff R13: 000055a715c0b040 R14: 00007fffb6f9fc80 R15: 000055a715c16660