Hello,
syzbot has tested the proposed patch but the reproducer still triggered
crash:
possible deadlock in usb_deregister_dev
usb 4-1: USB disconnect, device number 2
======================================================
WARNING: possible circular locking dependency detected
5.3.0-rc4+ #1 Not tainted
------------------------------------------------------
kworker/1:1/21 is trying to acquire lock:
00000000bfac431a (minor_rwsem){++++}, at: usb_deregister_dev
drivers/usb/core/file.c:238 [inline]
00000000bfac431a (minor_rwsem){++++}, at: usb_deregister_dev+0x61/0x270
drivers/usb/core/file.c:230
but task is already holding lock:
000000007638fa06 (iowarrior_open_disc_lock){+.+.}, at:
iowarrior_disconnect+0x45/0x2c0 drivers/usb/misc/iowarrior.c:867
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (iowarrior_open_disc_lock){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:930 [inline]
__mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
iowarrior_open+0x8a/0x2a0 drivers/usb/misc/iowarrior.c:600
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
-> #1 (iowarrior_mutex){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:930 [inline]
__mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077
iowarrior_open+0x23/0x2a0 drivers/usb/misc/iowarrior.c:589
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 drivers/usb/core/file.c:238 [inline]
usb_deregister_dev+0x61/0x270 drivers/usb/core/file.c:230
iowarrior_disconnect+0xa8/0x2c0 drivers/usb/misc/iowarrior.c:873
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:
Chain exists of:
minor_rwsem --> iowarrior_mutex --> iowarrior_open_disc_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(iowarrior_open_disc_lock);
lock(iowarrior_mutex);
lock(iowarrior_open_disc_lock);
lock(minor_rwsem);
*** DEADLOCK ***
6 locks held by kworker/1:1/21:
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at:
__write_once_size include/linux/compiler.h:226 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:855 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data
kernel/workqueue.c:620 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline]
#0: 00000000ffafc5b3 ((wq_completion)usb_hub_wq){+.+.}, at:
process_one_work+0x827/0x1530 kernel/workqueue.c:2240
#1: 000000005bc0df0d ((work_completion)(&hub->events)){+.+.}, at:
process_one_work+0x85b/0x1530 kernel/workqueue.c:2244
#2: 00000000f73a9504 (&dev->mutex){....}, at: device_lock
include/linux/device.h:1223 [inline]
#2: 00000000f73a9504 (&dev->mutex){....}, at: hub_event+0x17c/0x3640
drivers/usb/core/hub.c:5387
#3: 000000006fe9ca35 (&dev->mutex){....}, at: device_lock
include/linux/device.h:1223 [inline]
#3: 000000006fe9ca35 (&dev->mutex){....}, at: usb_disconnect+0x91/0x8d0
drivers/usb/core/hub.c:2190
#4: 0000000044c331cb (&dev->mutex){....}, at:
device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162
#5: 000000007638fa06 (iowarrior_open_disc_lock){+.+.}, at:
iowarrior_disconnect+0x45/0x2c0 drivers/usb/misc/iowarrior.c:867
stack backtrace:
CPU: 1 PID: 21 Comm: kworker/1:1 Not tainted 5.3.0-rc4+ #1
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 drivers/usb/core/file.c:238 [inline]
usb_deregister_dev+0x61/0x270 drivers/usb/core/file.c:230
iowarrior_disconnect+0xa8/0x2c0 drivers/usb/misc/iowarrior.c:873
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
iowarrior 4-1:0.236: I/O-Warror #0 now disconnected
usb 4-1: new low-speed USB device number 3 using dummy_hcd
usb 4-1: device descriptor read/all, error -71
usb 4-1: new low-speed USB device number 4 using dummy_hcd
usb 4-1: config 0 has an invalid interface number: 236 but max is 2
usb 4-1: config 0 has an invalid descriptor of length 99, skipping
remainder of the config
usb 4-1: config 0 has 1 interface, different from the descriptor's value: 3
usb 4-1: config 0 has no interface number 0
usb 4-1: config 0 interface 236 altsetting 0 endpoint 0x81 is Bulk;
changing to Interrupt
usb 4-1: New USB device found, idVendor=07c0, idProduct=1501,
bcdDevice=74.a0
usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 4-1: config 0 descriptor??
Tested on:
commit: d0847550 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=154c4522600000
kernel config: https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=11898be2600000
