Hello, syzbot found the following issue on: HEAD commit: 8280de6a usb: gadget: composite: Split composite reset and.. 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=1641df4f500000 kernel config: https://syzkaller.appspot.com/x/.config?x=c8ac36d562a4f043 dashboard link: https://syzkaller.appspot.com/bug?extid=495c6e4e8a6a71122a88 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+495c6e4e8a6a71122a88@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.11.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-shutdow state:D stack:22896 pid: 1 ppid: 0 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0x91b/0x1f90 kernel/sched/core.c:5064 schedule+0xcb/0x270 kernel/sched/core.c:5143 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:709 device_shutdown+0x18/0x5c0 drivers/base/core.c:4162 kernel_restart_prepare kernel/reboot.c:76 [inline] kernel_restart+0x61/0xa0 kernel/reboot.c:246 __do_sys_reboot+0x31e/0x3e0 kernel/reboot.c:349 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f8cdeac58c6 RSP: 002b:00007ffd16578bb8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8cdeac58c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffd16578c48 R08: 0000000000002800 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 000055cba9722150 R15: 00007ffd16578f38 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff8734ad08 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a3/0x3e0 kernel/reboot.c:346 6 locks held by kworker/0:0/5: #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888103f33938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x871/0x1580 kernel/workqueue.c:2246 #1: ffffc9000005fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1580 kernel/workqueue.c:2250 #2: ffff888109114218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:725 [inline] #2: ffff888109114218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537 #3: ffff88810dc1c218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:725 [inline] #3: ffff88810dc1c218 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:894 #4: ffff8881132111a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:725 [inline] #4: ffff8881132111a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:894 #5: ffff88810faecc60 (&dev->phy_mutex){+.+.}-{3:3}, at: asix_mdio_read+0x9a/0x320 drivers/net/usb/asix_common.c:452 1 lock held by khungtaskd/1268: #0: ffffffff8746d6a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6254 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1268 Comm: khungtaskd Not tainted 5.11.0-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:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 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:294 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 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.11.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_in+0x60/0x80 drivers/tty/serial/8250/8250_port.c:448 Code: 0f b6 8d f1 00 00 00 48 8d 7d 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 13 03 5d 40 89 da ec <5b> 0f b6 c0 5d c3 e8 35 8b 32 ff eb c9 e8 5e 8b 32 ff eb e6 66 90 RSP: 0018:ffffc9000005e8a0 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff8238ee4c RDI: ffffffff8a80f160 RBP: ffffffff8a80f120 R08: 0000000000000000 R09: 00000000000008fd R10: ffffffff811ae353 R11: 000000000000000a R12: 0000000000000020 R13: fffffbfff1501e77 R14: fffffbfff1501e2e R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd16577c3c CR3: 0000000104284000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:113 [inline] wait_for_xmitr+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:2061 serial8250_console_putchar+0x1b/0x50 drivers/tty/serial/8250/8250_port.c:3244 uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1946 serial8250_console_write+0x90c/0xa90 drivers/tty/serial/8250/8250_port.c:3316 call_console_drivers kernel/printk/printk.c:1838 [inline] console_unlock+0x848/0xb90 kernel/printk/printk.c:2552 vprintk_emit+0x1be/0x4a0 kernel/printk/printk.c:2074 dev_vprintk_emit+0x36e/0x3b2 drivers/base/core.c:4283 dev_printk_emit+0xba/0xf1 drivers/base/core.c:4294 __netdev_printk+0x1c6/0x27a net/core/dev.c:11039 netdev_warn+0xd7/0x109 net/core/dev.c:11092 asix_read_cmd.cold+0x3a/0x46 drivers/net/usb/asix_common.c:29 asix_mdio_read+0x149/0x320 drivers/net/usb/asix_common.c:458 asix_phy_reset+0x104/0x170 drivers/net/usb/asix_devices.c:215 ax88172_bind+0x412/0x5d0 drivers/net/usb/asix_devices.c:272 usbnet_probe+0xb70/0x27b0 drivers/net/usb/usbnet.c:1703 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 really_probe+0x291/0xde0 drivers/base/dd.c:561 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:745 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:851 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:919 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbc4/0x1d90 drivers/base/core.c:3091 usb_set_configuration+0x113c/0x1910 drivers/usb/core/message.c:2164 usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xde0 drivers/base/dd.c:561 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:745 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:851 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:919 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbc4/0x1d90 drivers/base/core.c:3091 usb_new_device.cold+0x71d/0xfe9 drivers/usb/core/hub.c:2555 hub_port_connect drivers/usb/core/hub.c:5223 [inline] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline] port_event drivers/usb/core/hub.c:5509 [inline] hub_event+0x2348/0x42d0 drivers/usb/core/hub.c:5591 process_one_work+0x98d/0x1580 kernel/workqueue.c:2275 process_scheduled_works kernel/workqueue.c:2337 [inline] worker_thread+0x82b/0x1120 kernel/workqueue.c:2423 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 --- 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.
