INFO: task syz-executor.0:5783 blocked for more than 140 seconds. Not tainted 4.14.218-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28688 5783 7973 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 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: 0033:0x465b09 RSP: 002b:00007fb3d5bd3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 00000000200002c0 RSI: 00000000c0185502 RDI: 0000000000000003 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe5c64193f R14: 00007fb3d5bd3300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1531: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1531 Comm: khungtaskd Not tainted 4.14.218-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.14.218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker task: ffff8880b55ee5c0 task.stack: ffff8880b55f8000 RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline] RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:417 [inline] RIP: 0010:batadv_nc_worker+0x14c/0xc50 net/batman-adv/network-coding.c:726 RSP: 0018:ffff8880b55ffcd8 EFLAGS: 00000a02 RAX: 1ffff11012596d62 RBX: ffff888092cb6b10 RCX: 1ffffffff11981ad RDX: 0000000000000000 RSI: ffffffff87ccd640 RDI: ffff8880ba522a4c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000020012 R10: ffff8880b55eee98 R11: ffff8880b55ee5c0 R12: dffffc0000000000 R13: ffff8880b5515c00 R14: ffff88813fe1a8c0 R15: ffff8880a4983400 FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9a8975f000 CR3: 00000000ab963000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 67 59 fa e8 e7 b1 5d fa 5a 85 c0 74 12 e8 0d ca 6c fa 80 3d cd 8e 0a 03 00 0f 84 b8 06 00 00 e8 fb c9 6c fa 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 bb 0a 00 00 48 8b 2b 48 85 ed 0f 84 fd 03