Hello, syzbot found the following issue on: HEAD commit: 3650b228 Linux 5.10-rc1 git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=141b20c0500000 kernel config: https://syzkaller.appspot.com/x/.config?x=b1c5bd23a80035ea dashboard link: https://syzkaller.appspot.com/bug?extid=6ac02052974329933524 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6ac02052974329933524@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.10.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:23432 pid: 1 ppid: 0 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x8a2/0x1f30 kernel/sched/core.c:4523 schedule+0xcb/0x270 kernel/sched/core.c:4601 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:702 device_shutdown+0x18/0x5c0 drivers/base/core.c:4009 kernel_restart_prepare kernel/reboot.c:76 [inline] kernel_restart kernel/reboot.c:246 [inline] __do_sys_reboot.cold+0x5d/0x97 kernel/reboot.c:347 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fe1cf5eb8c6 Code: Unable to access opcode bytes at RIP 0x7fe1cf5eb89c. RSP: 002b:00007ffcd3779e08 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe1cf5eb8c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffcd3779e98 R08: 0000000000002800 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 000055992d955150 R15: 00007ffcd377a188 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff871287a8 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a4/0x3e0 kernel/reboot.c:344 1 lock held by khungtaskd/1262: #0: ffffffff872491e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6259 5 locks held by kworker/1:2/2642: 5 locks held by kworker/1:4/6746: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1262 Comm: khungtaskd Not tainted 5.10.0-rc1-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+0x107/0x163 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x46/0xe0 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1da/0x200 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+0xd32/0xf70 kernel/hung_task.c:295 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:517 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
