Extracting prog: 1m41.370285105s
Minimizing prog: 2m38.654370208s
Simplifying prog options: 0s
Extracting C: 29.510687936s
Simplifying C: 3m28.649507678s


extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB="12011001000000085f0500a800010000000109022e0001010080320904000004ff00000007050102080000070582030800010705030240000007058402400000"], 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program crashed: possible deadlock in mdc800_device_open
program crashed: possible deadlock in mdc800_device_open
single: successfully extracted reproducer
found reproducer with 2 syscalls
minimizing guilty program
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB="12011001000000085f0500a800010000000109022e0001010080320904000004ff00000007050102080000070582030800010705030240000007058402400000"], 0x0)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, 0x0, 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB], 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program did not crash
extracting C reproducer
testing compiled C program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
simplifying C reproducer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:false Cgroups:false BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
program crashed: possible deadlock in mdc800_device_open
testing program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB="12011001000000085f0500a800010000000109022e0001010080320904000004ff00000007050102080000070582030800010705030240000007058402400000"], 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program crashed: possible deadlock in mdc800_device_open
validation run: crashed=true
testing program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB="12011001000000085f0500a800010000000109022e0001010080320904000004ff00000007050102080000070582030800010705030240000007058402400000"], 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program crashed: possible deadlock in mdc800_device_open
validation run: crashed=true
testing program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_usb_connect-syz_open_dev$char_usb
detailed listing:
executing program 0:
syz_usb_connect(0x0, 0x40, &(0x7f0000000000)=ANY=[@ANYBLOB="12011001000000085f0500a800010000000109022e0001010080320904000004ff00000007050102080000070582030800010705030240000007058402400000"], 0x0)
syz_open_dev$char_usb(0xc, 0xb4, 0x0)

program crashed: possible deadlock in mdc800_device_open
validation run: crashed=true
reproducing took 10m10.321126764s
repro crashed as (corrupted=false):
raw-gadget.0 gadget.0: fail, usb_ep_enable returned -22
raw-gadget.0 gadget.0: fail, usb_ep_enable returned -22
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/5924 is trying to acquire lock:
ffff888026c82218 (&mdc800->io_lock){+.+.}-{4:4}, at: mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611

but task is already holding lock:
ffffffff9028cda8 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (minor_rwsem#2){++++}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631
       usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
       mdc800_usb_probe+0x382/0x6d0 drivers/usb/image/mdc800.c:485
       usb_probe_interface+0x386/0x9b0 drivers/usb/core/driver.c:399
       call_driver_probe drivers/base/dd.c:628 [inline]
       really_probe+0x241/0xa60 drivers/base/dd.c:706
       __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
       driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
       __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
       bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
       __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
       device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
       bus_probe_device+0x64/0x160 drivers/base/bus.c:620
       device_add+0x121d/0x1970 drivers/base/core.c:3776
       usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
       usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
       usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293
       call_driver_probe drivers/base/dd.c:628 [inline]
       really_probe+0x241/0xa60 drivers/base/dd.c:706
       __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
       driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
       __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
       bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
       __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
       device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
       bus_probe_device+0x64/0x160 drivers/base/bus.c:620
       device_add+0x121d/0x1970 drivers/base/core.c:3776
       usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708
       usb_new_device include/linux/workqueue.h:715 [inline]
       hub_port_connect drivers/usb/core/hub.c:5580 [inline]
       hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
       port_event drivers/usb/core/hub.c:5884 [inline]
       hub_event.cold+0x1e3/0xe90 drivers/usb/core/hub.c:5966
       process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
       process_scheduled_works kernel/workqueue.c:3479 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
       kthread+0x373/0x450 kernel/kthread.c:436
       ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (&mdc800->io_lock){+.+.}-{4:4}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611
       usb_open+0x189/0x220 drivers/usb/core/file.c:47
       chrdev_open+0x234/0x6a0 fs/char_dev.c:411
       do_dentry_open+0x6ab/0x14d0 fs/open.c:996
       vfs_open+0x82/0x3f0 fs/open.c:1101
       do_open fs/namei.c:4837 [inline]
       path_openat+0x19fa/0x2440 fs/namei.c:5000
       do_file_open+0x20e/0x430 fs/namei.c:5029
       do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_openat fs/open.c:1439 [inline]
       __se_sys_openat fs/open.c:1434 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1434
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(minor_rwsem#2);
                               lock(&mdc800->io_lock);
                               lock(minor_rwsem#2);
  lock(&mdc800->io_lock);

 *** DEADLOCK ***

locks held by syz.0.17/5924: 1, last CPU#0:
 #0: ffffffff9028cda8 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38

stack backtrace:
CPU: 0 UID: 0 PID: 5924 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
 lock_acquire kernel/locking/lockdep.c:5908 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
 mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611
 usb_open+0x189/0x220 drivers/usb/core/file.c:47
 chrdev_open+0x234/0x6a0 fs/char_dev.c:411
 do_dentry_open+0x6ab/0x14d0 fs/open.c:996
 vfs_open+0x82/0x3f0 fs/open.c:1101
 do_open fs/namei.c:4837 [inline]
 path_openat+0x19fa/0x2440 fs/namei.c:5000
 do_file_open+0x20e/0x430 fs/namei.c:5029
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_openat fs/open.c:1439 [inline]
 __se_sys_openat fs/open.c:1434 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1434
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f288195e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffebffdd938 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000555567898500 RCX: 00007f288195e98e
RDX: 0000000000000002 RSI: 00007ffebffdda10 RDI: ffffffffffffff9c
RBP: 00007f2881a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2881c25fac R14: 00007f2881c25fa0 R15: 00007f2881c25fa0
 </TASK>

final repro crashed as (corrupted=false):
raw-gadget.0 gadget.0: fail, usb_ep_enable returned -22
raw-gadget.0 gadget.0: fail, usb_ep_enable returned -22
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/5924 is trying to acquire lock:
ffff888026c82218 (&mdc800->io_lock){+.+.}-{4:4}, at: mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611

but task is already holding lock:
ffffffff9028cda8 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (minor_rwsem#2){++++}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631
       usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
       mdc800_usb_probe+0x382/0x6d0 drivers/usb/image/mdc800.c:485
       usb_probe_interface+0x386/0x9b0 drivers/usb/core/driver.c:399
       call_driver_probe drivers/base/dd.c:628 [inline]
       really_probe+0x241/0xa60 drivers/base/dd.c:706
       __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
       driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
       __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
       bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
       __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
       device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
       bus_probe_device+0x64/0x160 drivers/base/bus.c:620
       device_add+0x121d/0x1970 drivers/base/core.c:3776
       usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
       usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
       usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293
       call_driver_probe drivers/base/dd.c:628 [inline]
       really_probe+0x241/0xa60 drivers/base/dd.c:706
       __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
       driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
       __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
       bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
       __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
       device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
       bus_probe_device+0x64/0x160 drivers/base/bus.c:620
       device_add+0x121d/0x1970 drivers/base/core.c:3776
       usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708
       usb_new_device include/linux/workqueue.h:715 [inline]
       hub_port_connect drivers/usb/core/hub.c:5580 [inline]
       hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
       port_event drivers/usb/core/hub.c:5884 [inline]
       hub_event.cold+0x1e3/0xe90 drivers/usb/core/hub.c:5966
       process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
       process_scheduled_works kernel/workqueue.c:3479 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
       kthread+0x373/0x450 kernel/kthread.c:436
       ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (&mdc800->io_lock){+.+.}-{4:4}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611
       usb_open+0x189/0x220 drivers/usb/core/file.c:47
       chrdev_open+0x234/0x6a0 fs/char_dev.c:411
       do_dentry_open+0x6ab/0x14d0 fs/open.c:996
       vfs_open+0x82/0x3f0 fs/open.c:1101
       do_open fs/namei.c:4837 [inline]
       path_openat+0x19fa/0x2440 fs/namei.c:5000
       do_file_open+0x20e/0x430 fs/namei.c:5029
       do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_openat fs/open.c:1439 [inline]
       __se_sys_openat fs/open.c:1434 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1434
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(minor_rwsem#2);
                               lock(&mdc800->io_lock);
                               lock(minor_rwsem#2);
  lock(&mdc800->io_lock);

 *** DEADLOCK ***

locks held by syz.0.17/5924: 1, last CPU#0:
 #0: ffffffff9028cda8 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38

stack backtrace:
CPU: 0 UID: 0 PID: 5924 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
 lock_acquire kernel/locking/lockdep.c:5908 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
 mdc800_device_open+0x22/0x450 drivers/usb/image/mdc800.c:611
 usb_open+0x189/0x220 drivers/usb/core/file.c:47
 chrdev_open+0x234/0x6a0 fs/char_dev.c:411
 do_dentry_open+0x6ab/0x14d0 fs/open.c:996
 vfs_open+0x82/0x3f0 fs/open.c:1101
 do_open fs/namei.c:4837 [inline]
 path_openat+0x19fa/0x2440 fs/namei.c:5000
 do_file_open+0x20e/0x430 fs/namei.c:5029
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_openat fs/open.c:1439 [inline]
 __se_sys_openat fs/open.c:1434 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1434
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f288195e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffebffdd938 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000555567898500 RCX: 00007f288195e98e
RDX: 0000000000000002 RSI: 00007ffebffdda10 RDI: ffffffffffffff9c
RBP: 00007f2881a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2881c25fac R14: 00007f2881c25fa0 R15: 00007f2881c25fa0
 </TASK>