======================================================
WARNING: possible circular locking dependency detected
5.3.0-rc7+ #0 Not tainted
------------------------------------------------------
syz-executor.4/10003 is trying to acquire lock:
00000000533be610 (rio500_mutex){+.+.}, at: open_rio+0x16/0xe0 drivers/usb/misc/rio500.c:65

but task is already holding lock:
00000000c0e1d9d7 (minor_rwsem){++++}, at: usb_open+0x23/0x270 drivers/usb/core/file.c:39

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (minor_rwsem){++++}:
       down_write+0x92/0x150 kernel/locking/rwsem.c:1500
       usb_register_dev drivers/usb/core/file.c:187 [inline]
       usb_register_dev+0x131/0x670 drivers/usb/core/file.c:156
       probe_rio.cold+0x53/0x237 drivers/usb/misc/rio500.c:474
       usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
       really_probe+0x281/0x6d0 drivers/base/dd.c:548
       driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
       __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
       bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
       __device_attach+0x217/0x360 drivers/base/dd.c:894
       bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
       device_add+0xae6/0x16f0 drivers/base/core.c:2165
       usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
       generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
       usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
       really_probe+0x281/0x6d0 drivers/base/dd.c:548
       driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
       __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
       bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
       __device_attach+0x217/0x360 drivers/base/dd.c:894
       bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
       device_add+0xae6/0x16f0 drivers/base/core.c:2165
       usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
       hub_port_connect drivers/usb/core/hub.c:5098 [inline]
       hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
       port_event drivers/usb/core/hub.c:5359 [inline]
       hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
       process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
       process_scheduled_works kernel/workqueue.c:2331 [inline]
       worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
       kthread+0x318/0x420 kernel/kthread.c:255
       ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

-> #0 (rio500_mutex){+.+.}:
       check_prev_add kernel/locking/lockdep.c:2405 [inline]
       check_prevs_add kernel/locking/lockdep.c:2507 [inline]
       validate_chain kernel/locking/lockdep.c:2897 [inline]
       __lock_acquire+0x1f7c/0x3b50 kernel/locking/lockdep.c:3880
       lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412
       __mutex_lock_common kernel/locking/mutex.c:930 [inline]
       __mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
       open_rio+0x16/0xe0 drivers/usb/misc/rio500.c:65
       usb_open+0x1df/0x270 drivers/usb/core/file.c:48
       chrdev_open+0x219/0x5c0 fs/char_dev.c:414
       do_dentry_open+0x494/0x1120 fs/open.c:797
       do_last fs/namei.c:3416 [inline]
       path_openat+0x1430/0x3f50 fs/namei.c:3533
       do_filp_open+0x1a1/0x280 fs/namei.c:3563
       do_sys_open+0x3c0/0x580 fs/open.c:1089
       do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(minor_rwsem);
                               lock(rio500_mutex);
                               lock(minor_rwsem);
  lock(rio500_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor.4/10003:
 #0: 00000000c0e1d9d7 (minor_rwsem){++++}, at: usb_open+0x23/0x270 drivers/usb/core/file.c:39

stack backtrace:
CPU: 1 PID: 10003 Comm: syz-executor.4 Not tainted 5.3.0-rc7+ #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+0xca/0x13e lib/dump_stack.c:113
 check_noncircular+0x345/0x3e0 kernel/locking/lockdep.c:1741
 check_prev_add kernel/locking/lockdep.c:2405 [inline]
 check_prevs_add kernel/locking/lockdep.c:2507 [inline]
 validate_chain kernel/locking/lockdep.c:2897 [inline]
 __lock_acquire+0x1f7c/0x3b50 kernel/locking/lockdep.c:3880
 lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412
 __mutex_lock_common kernel/locking/mutex.c:930 [inline]
 __mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
 open_rio+0x16/0xe0 drivers/usb/misc/rio500.c:65
 usb_open+0x1df/0x270 drivers/usb/core/file.c:48
 chrdev_open+0x219/0x5c0 fs/char_dev.c:414
 do_dentry_open+0x494/0x1120 fs/open.c:797
 do_last fs/namei.c:3416 [inline]
 path_openat+0x1430/0x3f50 fs/namei.c:3533
 do_filp_open+0x1a1/0x280 fs/namei.c:3563
 do_sys_open+0x3c0/0x580 fs/open.c:1089
 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4137d1
Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f2343ce67a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004137d1
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f2343ce6850
RBP: 000000000075bf20 R08: 00007f2343ce67b0 R09: 000000000075bf20
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f2343ce76d4
R13: 00000000004c8cbf R14: 00000000004dfc90 R15: 00000000ffffffff
usb 3-1: Rio opened.