block nbd1: Device being setup by another task block nbd1: shutting down sockets INFO: task syz-executor.1:12044 blocked for more than 140 seconds. Not tainted 4.14.256-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28912 12044 7984 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 flush_workqueue+0x3ce/0x1310 kernel/workqueue.c:2677 nbd_start_device_ioctl drivers/block/nbd.c:1263 [inline] __nbd_ioctl drivers/block/nbd.c:1334 [inline] nbd_ioctl+0x49d/0xa80 drivers/block/nbd.c:1374 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f265fd02ae9 RSP: 002b:00007f265ec78188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f265fe15f60 RCX: 00007f265fd02ae9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f265fd5cff7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe99e1784f R14: 00007f265ec78300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1523: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/7673: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 2 locks held by kworker/u5:5/8047: #0: ("knbd%d-recv"nbd->index){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((&args->work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1523 Comm: khungtaskd Not tainted 4.14.256-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4616 Comm: systemd-journal Not tainted 4.14.256-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a19e8640 task.stack: ffff8880a19f0000 RIP: 0010:memcmp+0x37/0xb0 lib/string.c:918 RSP: 0018:ffff8880a19f7b28 EFLAGS: 00000a07 RAX: 1ffff1101433ef7d RBX: ffff8880a19f7bef RCX: 0000000000000006 RDX: ffff8880a19f7bef RSI: ffff8880a46be4ef RDI: ffff8880a19f7bc8 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffff8880a19e8640 R12: ffff8880a19f7bf8 R13: 0000000000000006 R14: ffff8880a19f7bc8 R15: ffff8880a46be4b0 FS: 00007fa3e54698c0(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa3e28a6000 CR3: 00000000a1eac000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: find_stack lib/stackdepot.c:180 [inline] depot_save_stack+0x10d/0x3f0 lib/stackdepot.c:229 save_stack mm/kasan/kasan.c:453 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0x139/0x160 mm/kasan/kasan.c:551 slab_post_alloc_hook mm/slab.h:442 [inline] slab_alloc mm/slab.c:3390 [inline] kmem_cache_alloc+0x111/0x3c0 mm/slab.c:3550 prepare_creds+0x39/0x490 kernel/cred.c:255 SYSC_faccessat fs/open.c:365 [inline] SyS_faccessat+0x7b/0x680 fs/open.c:353 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fa3e47249c7 RSP: 002b:00007ffe54c634c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffe54c664f0 RCX: 00007fa3e47249c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005609715169a3 RBP: 00007ffe54c63610 R08: 000056097150c3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000560972d728a0 R15: 00007ffe54c63b00 Code: 48 bd 00 00 00 00 00 fc ff df 53 48 89 fb 48 83 ec 10 eb 0d 48 83 c3 01 48 83 c6 01 49 39 dc 74 45 48 89 d8 48 89 da 48 c1 e8 03 <83> e2 07 0f b6 04 28 38 d0 7f 04 84 c0 75 54 48 89 f2 48 89 f1 ---------------- Code disassembly (best guess): 0: 48 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%rbp 7: fc ff df a: 53 push %rbx b: 48 89 fb mov %rdi,%rbx e: 48 83 ec 10 sub $0x10,%rsp 12: eb 0d jmp 0x21 14: 48 83 c3 01 add $0x1,%rbx 18: 48 83 c6 01 add $0x1,%rsi 1c: 49 39 dc cmp %rbx,%r12 1f: 74 45 je 0x66 21: 48 89 d8 mov %rbx,%rax 24: 48 89 da mov %rbx,%rdx 27: 48 c1 e8 03 shr $0x3,%rax * 2b: 83 e2 07 and $0x7,%edx <-- trapping instruction 2e: 0f b6 04 28 movzbl (%rax,%rbp,1),%eax 32: 38 d0 cmp %dl,%al 34: 7f 04 jg 0x3a 36: 84 c0 test %al,%al 38: 75 54 jne 0x8e 3a: 48 89 f2 mov %rsi,%rdx 3d: 48 89 f1 mov %rsi,%rcx