possible deadlock in usb_deregister_dev (2)

From: syzbot
Date: Mon Sep 16 2019 - 12:09:14 EST

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Hello,

syzbot found the following crash on:

HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=1742f159600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=f9549f5ee8a5416f0b95
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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+f9549f5ee8a5416f0b95@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 5-1: USB disconnect, device number 27
======================================================
WARNING: possible circular locking dependency detected
5.3.0-rc7+ #0 Not tainted
------------------------------------------------------
kworker/1:5/2876 is trying to acquire lock:
000000006f0f0bc3 (minor_rwsem){++++}, at: usb_deregister_dev+0x95/0x230 drivers/usb/core/file.c:239

but task is already holding lock:
00000000175691a3 (open_disc_mutex){+.+.}, at: tower_disconnect+0x45/0x300 drivers/usb/misc/legousbtower.c:945

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (open_disc_mutex){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:930 [inline]
__mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
tower_open+0xce/0x9b0 drivers/usb/misc/legousbtower.c:335
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

-> #0 (minor_rwsem){++++}:
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
down_write+0x92/0x150 kernel/locking/rwsem.c:1500
usb_deregister_dev+0x95/0x230 drivers/usb/core/file.c:239
tower_disconnect+0xa8/0x300 drivers/usb/misc/legousbtower.c:951
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

other info that might help us debug this:

Possible unsafe locking scenario:

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

*** DEADLOCK ***

6 locks held by kworker/1:5/2876:
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline]
#0: 00000000ecb9dcf5 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x1530 kernel/workqueue.c:2240
#1: 0000000009747c0c ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x1530 kernel/workqueue.c:2244
#2: 000000004bd4f175 (&dev->mutex){....}, at: device_lock include/linux/device.h:1223 [inline]
#2: 000000004bd4f175 (&dev->mutex){....}, at: hub_event+0x17c/0x3640 drivers/usb/core/hub.c:5387
#3: 00000000668c8b60 (&dev->mutex){....}, at: device_lock include/linux/device.h:1223 [inline]
#3: 00000000668c8b60 (&dev->mutex){....}, at: usb_disconnect+0x91/0x8d0 drivers/usb/core/hub.c:2190
#4: 00000000787026a9 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162
#5: 00000000175691a3 (open_disc_mutex){+.+.}, at: tower_disconnect+0x45/0x300 drivers/usb/misc/legousbtower.c:945

stack backtrace:
CPU: 1 PID: 2876 Comm: kworker/1:5 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
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
down_write+0x92/0x150 kernel/locking/rwsem.c:1500
usb_deregister_dev+0x95/0x230 drivers/usb/core/file.c:239
tower_disconnect+0xa8/0x300 drivers/usb/misc/legousbtower.c:951
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
legousbtower 5-1:0.219: LEGO USB Tower #-160 now disconnected
usb 5-1: new high-speed USB device number 28 using dummy_hcd
usb 5-1: device descriptor read/64, error 18
usb 5-1: device descriptor read/64, error 18
usb 5-1: new high-speed USB device number 29 using dummy_hcd
usb 5-1: device descriptor read/64, error 18
usb 5-1: device descriptor read/64, error 18
usb usb5-port1: attempt power cycle
usb 5-1: new high-speed USB device number 30 using dummy_hcd
usb 4-1: new high-speed USB device number 9 using dummy_hcd
usb 4-1: Using ep0 maxpacket: 16
usb 4-1: config 0 interface 0 altsetting 0 endpoint 0x81 has an invalid bInterval 0, changing to 7
usb 4-1: config 0 interface 0 altsetting 0 has 1 endpoint descriptor, different from the interface descriptor's value: 9
usb 4-1: New USB device found, idVendor=0d8c, idProduct=0022, bcdDevice= 0.00
usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 4-1: config 0 descriptor??
usbhid 4-1:0.0: can't add hid device: -71
usbhid: probe of 4-1:0.0 failed with error -71
usb 4-1: USB disconnect, device number 9

---
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Next message: shuah: "Re: [PATCH] selftests/net: replace AF_MAX with INT_MAX in socket.c"
Previous message: syzbot: "memory leak in h5_rx_pkt_start"
Next in thread: syzbot: "Re: possible deadlock in usb_deregister_dev (2)"
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