INFO: task syz-executor.3:13556 can't die for more than 143 seconds. syz-executor.3 D24312 13556 7142 0x00004004 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8f3/0x1f80 kernel/sched/core.c:4155 schedule+0xd0/0x2a0 kernel/sched/core.c:4230 schedule_timeout+0x454/0x850 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+0x16a/0x270 kernel/sched/completion.c:138 flush_workqueue+0x403/0x14f0 kernel/workqueue.c:2831 nbd_start_device_ioctl drivers/block/nbd.c:1322 [inline] __nbd_ioctl drivers/block/nbd.c:1397 [inline] nbd_ioctl+0x7aa/0xb75 drivers/block/nbd.c:1437 __blkdev_driver_ioctl block/ioctl.c:224 [inline] blkdev_ioctl+0x25e/0x6c0 block/ioctl.c:620 block_ioctl+0xf9/0x140 fs/block_dev.c:1987 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:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ca59 Code: Bad RIP value. RSP: 002b:00007f83ea901c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e98c0 RCX: 000000000045ca59 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000415 R14: 00000000004c6d6f R15: 00007f83ea9026d4 INFO: task syz-executor.3:13556 blocked for more than 143 seconds. Not tainted 5.7.0-rc7-next-20200529-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24312 13556 7142 0x00004004 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8f3/0x1f80 kernel/sched/core.c:4155 schedule+0xd0/0x2a0 kernel/sched/core.c:4230 schedule_timeout+0x454/0x850 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+0x16a/0x270 kernel/sched/completion.c:138 flush_workqueue+0x403/0x14f0 kernel/workqueue.c:2831 nbd_start_device_ioctl drivers/block/nbd.c:1322 [inline] __nbd_ioctl drivers/block/nbd.c:1397 [inline] nbd_ioctl+0x7aa/0xb75 drivers/block/nbd.c:1437 __blkdev_driver_ioctl block/ioctl.c:224 [inline] blkdev_ioctl+0x25e/0x6c0 block/ioctl.c:620 block_ioctl+0xf9/0x140 fs/block_dev.c:1987 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:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ca59 Code: Bad RIP value. RSP: 002b:00007f83ea901c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e98c0 RCX: 000000000045ca59 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000415 R14: 00000000004c6d6f R15: 00007f83ea9026d4 Showing all locks held in the system: 1 lock held by khungtaskd/1149: #0: ffffffff89bbde00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6544: #0: ffff888097573b70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by kworker/u5:1/13562: #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88809431a138 ((wq_completion)knbd3-recv){+.+.}-{0:0}, at: process_one_work+0x844/0x1690 kernel/workqueue.c:2239 #1: ffffc90001887dc0 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x878/0x1690 kernel/workqueue.c:2243 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1149 Comm: khungtaskd Not tainted 5.7.0-rc7-next-20200529-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+0x1e6/0x221 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xf97/0x14e0 kernel/hung_task.c:339 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3874 Comm: systemd-journal Not tainted 5.7.0-rc7-next-20200529-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__d_lookup_rcu+0x0/0x6a0 fs/dcache.c:2236 Code: 24 00 00 00 40 e8 00 0b b0 ff 4c 89 e0 5d 41 5c c3 4c 89 e7 e8 11 14 ef ff eb e2 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 41 56 41 55 41 54 55 53 48 89 f3 48 83 ec 60 48 89 54 24 38 RSP: 0018:ffffc90001577a28 EFLAGS: 00000293 RAX: ffff88809396e2c0 RBX: 1ffff920002aef48 RCX: ffffffff81bfe7c0 RDX: ffffc90001577a60 RSI: ffffc90001577d20 RDI: ffff8882180c18a0 RBP: ffffc90001577d10 R08: ffff88809396e2c0 R09: 0000000000000001 R10: 000000000000001c R11: 0000000000000000 R12: ffffc90001577d20 R13: ffffc90001577b10 R14: ffff8882180c18a0 R15: ffffc90001577d48 FS: 00007fe9769e58c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c016fc40c0 CR3: 0000000093c24000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lookup_fast+0xe0/0x6c0 fs/namei.c:1453 walk_component+0xc6/0x6a0 fs/namei.c:1842 link_path_walk.part.0+0x631/0xb50 fs/namei.c:2169 link_path_walk fs/namei.c:2097 [inline] path_lookupat.isra.0+0x8d/0x530 fs/namei.c:2318 filename_lookup+0x1a3/0x3e0 fs/namei.c:2352 user_path_at include/linux/namei.h:59 [inline] do_faccessat+0x12c/0x830 fs/open.c:423 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fe975ca19c7 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:00007ffcbf5e4408 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffcbf5e7320 RCX: 00007fe975ca19c7 RDX: 00007fe976712a00 RSI: 0000000000000000 RDI: 000056415804b9a3 RBP: 00007ffcbf5e4440 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffcbf5e7320 R15: 00007ffcbf5e4930