INFO: task syz-executor160:8002 blocked for more than 140 seconds. Not tainted 4.14.279-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor160 D26560 8002 8001 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 usb_start_wait_urb+0x125/0x440 drivers/usb/core/message.c:61 usb_bulk_msg+0x1f6/0x500 drivers/usb/core/message.c:252 proc_bulk+0x331/0x6d0 drivers/usb/core/devio.c:1223 usbdev_do_ioctl+0x5b0/0x2b70 drivers/usb/core/devio.c:2449 usbdev_ioctl+0x21/0x30 drivers/usb/core/devio.c:2599 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: 0033:0x7fb8321aa3b9 RSP: 002b:00007ffd26dbd498 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb8321aa3b9 RDX: 0000000020000200 RSI: 00000000c0185502 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffd26dbd638 R09: 00007ffd26dbd638 R10: 00007ffd26dbcf10 R11: 0000000000000246 R12: 00007fb8321696d0 R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1534: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1534 Comm: khungtaskd Not tainted 4.14.279-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: 3 Comm: kworker/0:0 Not tainted 4.14.279-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_long gc_worker task: ffff8880b5fe80c0 task.stack: ffff8880b5ff0000 RIP: 0010:lock_release+0x139/0x870 kernel/locking/lockdep.c:4015 RSP: 0018:ffff8880b5ff7c48 EFLAGS: 00000046 RAX: 0000000000000007 RBX: 1ffff11016bfef8c RCX: 0000000000006449 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8880b5fe8944 RBP: ffffffff8a09e348 R08: ffffffff8b9d7d08 R09: 00000000000e036f R10: 0000000000000000 R11: ffff8880b5fe80c0 R12: ffffffff81365063 R13: ffff8880b5fe80c0 R14: 0000000000010000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc45c6ad000 CR3: 00000000a1ff0000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: seqcount_lockdep_reader_access include/linux/seqlock.h:82 [inline] read_seqcount_begin include/linux/seqlock.h:164 [inline] nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:304 [inline] gc_worker+0x201/0xb50 net/netfilter/nf_conntrack_core.c:1086 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 fa 04 00 00 <41> c7 85 84 08 00 00 01 00 00 00 0f 1f 44 00 00 65 8b 05 00 52 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 7: fc ff df a: 48 89 fa mov %rdi,%rdx d: 48 c1 ea 03 shr $0x3,%rdx 11: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx 15: 48 89 f8 mov %rdi,%rax 18: 83 e0 07 and $0x7,%eax 1b: 83 c0 03 add $0x3,%eax 1e: 38 d0 cmp %dl,%al 20: 7c 08 jl 0x2a 22: 84 d2 test %dl,%dl 24: 0f 85 fa 04 00 00 jne 0x524 * 2a: 41 c7 85 84 08 00 00 movl $0x1,0x884(%r13) <-- trapping instruction 31: 01 00 00 00 35: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 3a: 65 gs 3b: 8b .byte 0x8b 3c: 05 .byte 0x5 3d: 00 .byte 0x0 3e: 52 push %rdx