Hello, syzbot found the following crash on: HEAD commit: 768a0741 usb: dwc2: gadget: Remove assigned but never used.. 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=14bc067b100000 kernel config: https://syzkaller.appspot.com/x/.config?x=999be4eb2478ffa5 dashboard link: https://syzkaller.appspot.com/bug?extid=e761775e8f4a28711f19 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e761775e8f4a28711f19@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task kworker/0:6:3156 blocked for more than 143 seconds. Not tainted 5.8.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:6 D23384 3156 2 0x80004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x88a/0x1cb0 kernel/sched/core.c:4178 schedule+0xcd/0x2b0 kernel/sched/core.c:4253 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x13c/0x150 kernel/locking/rwsem.c:1532 usb_register_dev drivers/usb/core/file.c:187 [inline] usb_register_dev+0x19d/0x740 drivers/usb/core/file.c:156 adu_probe+0x6a3/0x830 drivers/usb/misc/adutux.c:733 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:374 really_probe+0x291/0xc90 drivers/base/dd.c:525 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:701 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:807 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x28d/0x430 drivers/base/dd.c:873 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb09/0x1b40 drivers/base/core.c:2680 usb_set_configuration+0xf05/0x18a0 drivers/usb/core/message.c:2032 usb_generic_driver_probe+0xba/0xf2 drivers/usb/core/generic.c:241 usb_probe_device+0xd9/0x250 drivers/usb/core/driver.c:272 really_probe+0x291/0xc90 drivers/base/dd.c:525 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:701 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:807 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x28d/0x430 drivers/base/dd.c:873 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb09/0x1b40 drivers/base/core.c:2680 usb_new_device.cold+0x71d/0xfd4 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x2361/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 INFO: task kworker/0:0:15224 blocked for more than 143 seconds. Not tainted 5.8.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:0 D23480 15224 2 0x80004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x88a/0x1cb0 kernel/sched/core.c:4178 schedule+0xcd/0x2b0 kernel/sched/core.c:4253 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x13c/0x150 kernel/locking/rwsem.c:1532 usb_deregister_dev+0xaa/0x300 drivers/usb/core/file.c:239 wdm_disconnect+0x21/0x450 drivers/usb/class/cdc-wdm.c:979 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:436 __device_release_driver+0x3b7/0x6e0 drivers/base/dd.c:1113 device_release_driver_internal drivers/base/dd.c:1144 [inline] device_release_driver+0x26/0x40 drivers/base/dd.c:1167 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x47c/0xd20 drivers/base/core.c:2857 usb_disable_device+0x387/0x930 drivers/usb/core/message.c:1245 usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2217 hub_port_connect drivers/usb/core/hub.c:5059 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x1c93/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 INFO: task syz-executor.1:3812 blocked for more than 144 seconds. Not tainted 5.8.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D29352 3812 346 0x00000004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x88a/0x1cb0 kernel/sched/core.c:4178 schedule+0xcd/0x2b0 kernel/sched/core.c:4253 rwsem_down_read_slowpath+0x2f7/0xc90 kernel/locking/rwsem.c:1099 __down_read kernel/locking/rwsem.c:1341 [inline] down_read+0x1f0/0x420 kernel/locking/rwsem.c:1494 usb_open+0x23/0x270 drivers/usb/core/file.c:39 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4ff/0x1170 fs/open.c:828 do_open fs/namei.c:3243 [inline] path_openat+0x192c/0x26b0 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x50/0x90 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x416921 Code: Bad RIP value. RSP: 002b:00007f3dc9c297a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000050a8c0 RCX: 0000000000416921 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007f3dc9c297d0 RBP: 000000000078bf00 R08: 0000000000000000 R09: 000000000000000f R10: 0000000000000064 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000c46 R14: 00000000004ce9a6 R15: 00007f3dc9c2a6d4 INFO: task syz-executor.4:3919 blocked for more than 144 seconds. Not tainted 5.8.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29160 3919 343 0x00000004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x88a/0x1cb0 kernel/sched/core.c:4178 schedule+0xcd/0x2b0 kernel/sched/core.c:4253 rwsem_down_read_slowpath+0x2f7/0xc90 kernel/locking/rwsem.c:1099 __down_read kernel/locking/rwsem.c:1341 [inline] down_read+0x1f0/0x420 kernel/locking/rwsem.c:1494 usb_open+0x23/0x270 drivers/usb/core/file.c:39 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4ff/0x1170 fs/open.c:828 do_open fs/namei.c:3243 [inline] path_openat+0x192c/0x26b0 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x50/0x90 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x416921 Code: Bad RIP value. RSP: 002b:00007f33da2f47a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000050a8c0 RCX: 0000000000416921 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007f33da2f47d0 RBP: 000000000078bf00 R08: 0000000000000000 R09: 000000000000000f R10: 0000000000000064 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000c46 R14: 00000000004ce9a6 R15: 00007f33da2f56d4 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: ffffffff873124a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/237: #0: ffff8881c717aaf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/240: #0: ffff8881d1b94098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000a022e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 6 locks held by kworker/0:4/3138: #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240 #1: ffff8881cfd1fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244 #2: ffff8881d453d218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #2: ffff8881d453d218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x4390 drivers/usb/core/hub.c:5522 #3: ffff8881d21b6218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #3: ffff8881d21b6218 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850 #4: ffff8881cb5fd1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #4: ffff8881cb5fd1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850 #5: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev drivers/usb/core/file.c:187 [inline] #5: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev+0x19d/0x740 drivers/usb/core/file.c:156 6 locks held by kworker/0:6/3156: #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240 #1: ffff8881ccc37da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244 #2: ffff8881d4465218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #2: ffff8881d4465218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x4390 drivers/usb/core/hub.c:5522 #3: ffff8881cabba218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #3: ffff8881cabba218 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850 #4: ffff8881ce3491a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #4: ffff8881ce3491a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x430 drivers/base/dd.c:850 #5: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev drivers/usb/core/file.c:187 [inline] #5: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_register_dev+0x19d/0x740 drivers/usb/core/file.c:156 6 locks held by kworker/0:0/15224: #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8881d880ed38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x82b/0x15f0 kernel/workqueue.c:2240 #1: ffff8881cc307da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x85f/0x15f0 kernel/workqueue.c:2244 #2: ffff8881d441d218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #2: ffff8881d441d218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x4390 drivers/usb/core/hub.c:5522 #3: ffff8881d2745218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #3: ffff8881d2745218 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x780 drivers/usb/core/hub.c:2208 #4: ffff8881c809d1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:768 [inline] #4: ffff8881c809d1a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:936 [inline] #4: ffff8881c809d1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1141 [inline] #4: ffff8881c809d1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1167 #5: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_deregister_dev+0xaa/0x300 drivers/usb/core/file.c:239 2 locks held by agetty/18569: #0: ffff8881c8d0d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000f9c42e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/3409: #0: ffff8881ce34b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000fd982e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/3840: #0: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x23/0x270 drivers/usb/core/file.c:39 #1: ffff8881c954b0d0 (&(sisusb->lock)){+.+.}-{3:3}, at: sisusb_open+0xb2/0x4d0 drivers/usb/misc/sisusbvga/sisusb.c:2396 1 lock held by syz-executor.1/3812: #0: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x23/0x270 drivers/usb/core/file.c:39 1 lock held by syz-executor.4/3919: #0: ffffffff878ac990 (minor_rwsem#2){++++}-{3:3}, at: usb_open+0x23/0x270 drivers/usb/core/file.c:39 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.8.0-rc3-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+0xf6/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x74/0xb6 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1da/0x1f4 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+0xd6a/0xfd0 kernel/hung_task.c:295 kthread+0x392/0x470 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x72/0x90 drivers/acpi/processor_idle.c:111 --- This bug 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 bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
