[syzbot] [usb?] possible deadlock in usb_deregister_dev (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a9fe2a8ac53 dt-bindings: usb: dwc3-imx8mp: add compatible..
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=1675cd27980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4510af5d637450fb
dashboard link: https://syzkaller.appspot.com/bug?extid=1f8ca5ee82576ec01f12
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16107bd0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14983307980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/883c5319cb52/disk-4a9fe2a8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/caf4421ed2ef/vmlinux-4a9fe2a8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d8e3beb01d49/bzImage-4a9fe2a8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1f8ca5...@syzkaller.appspotmail.com

chaoskey 2-1:0.0: Unable to register with hwrng
usb 1-1: USB disconnect, device number 2
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted
------------------------------------------------------
kworker/0:2/804 is trying to acquire lock:
ffffffff899dadb0 (minor_rwsem){++++}-{3:3}, at: usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186

but task is already holding lock:
ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (chaoskey_list_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
chaoskey_open+0xdd/0x220 drivers/usb/misc/chaoskey.c:274
usb_open+0x186/0x220 drivers/usb/core/file.c:47
chrdev_open+0x237/0x6a0 fs/char_dev.c:414
do_dentry_open+0x6cb/0x1390 fs/open.c:958
vfs_open+0x82/0x3f0 fs/open.c:1088
do_open fs/namei.c:3774 [inline]
path_openat+0x1e6a/0x2d60 fs/namei.c:3933
do_filp_open+0x1dc/0x430 fs/namei.c:3960
do_sys_openat2+0x17a/0x1e0 fs/open.c:1415
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (minor_rwsem){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186
chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236
usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x122/0x170 drivers/base/dd.c:561
__device_release_driver drivers/base/dd.c:1273 [inline]
device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296
bus_remove_device+0x22f/0x420 drivers/base/bus.c:576
device_del+0x396/0x9f0 drivers/base/core.c:3864
usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418
usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304
hub_port_connect drivers/usb/core/hub.c:5361 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
port_event drivers/usb/core/hub.c:5821 [inline]
hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Possible unsafe locking scenario:

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

*** DEADLOCK ***

6 locks held by kworker/0:2/804:
#0: ffff888106684148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x129b/0x1ba0 kernel/workqueue.c:3204
#1: ffffc90001c2fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205
#2: ffff888109b0b190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline]
#2: ffff888109b0b190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5849
#3: ffff8881027fd190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline]
#3: ffff8881027fd190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x920 drivers/usb/core/hub.c:2295
#4: ffff888107af6160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline]
#4: ffff888107af6160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline]
#4: ffff888107af6160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1293
#5: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235

stack backtrace:
CPU: 0 UID: 0 PID: 804 Comm: kworker/0:2 Not tainted 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186
chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236
usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x122/0x170 drivers/base/dd.c:561
__device_release_driver drivers/base/dd.c:1273 [inline]
device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296
bus_remove_device+0x22f/0x420 drivers/base/bus.c:576
device_del+0x396/0x9f0 drivers/base/core.c:3864
usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418
usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304
hub_port_connect drivers/usb/core/hub.c:5361 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
port_event drivers/usb/core/hub.c:5821 [inline]
hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
usb 1-1: new high-speed USB device number 3 using dummy_hcd
usb 1-1: Using ep0 maxpacket: 32
usb 1-1: config 0 interface 0 altsetting 0 bulk endpoint 0x85 has invalid maxpacket 1024
usb 1-1: New USB device found, idVendor=12d8, idProduct=0001, bcdDevice=de.79
usb 1-1: New USB device strings: Mfr=1, Product=236, SerialNumber=2
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: config 0 descriptor??
chaoskey 1-1:0.0: Unable to register with hwrng


---
This report 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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Edward Adam Davis]

delay get the chaoskey_list_lock, avoid to circular locking dependency

#syz test

diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
index e8b63df5f975..17e29c6e878b 100644
--- a/drivers/usb/misc/chaoskey.c
+++ b/drivers/usb/misc/chaoskey.c
@@ -232,10 +232,10 @@ static void chaoskey_disconnect(struct usb_interface *interface)
if (dev->hwrng_registered)
hwrng_unregister(&dev->hwrng);

- mutex_lock(&chaoskey_list_lock);
usb_deregister_dev(interface, &chaoskey_class);

usb_set_intfdata(interface, NULL);
+ mutex_lock(&chaoskey_list_lock);
mutex_lock(&dev->lock);

dev->present = false;

[Edward Adam Davis]

delay get the chaoskey_list_lock, avoid to circular locking dependency

chaoskey_release has a wrong logic lock for chaoskey_list_lock, it need unlock.

#syz test

diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c

index e8b63df5f975..225863321dc4 100644

--- a/drivers/usb/misc/chaoskey.c
+++ b/drivers/usb/misc/chaoskey.c
@@ -232,10 +232,10 @@ static void chaoskey_disconnect(struct usb_interface *interface)
if (dev->hwrng_registered)
hwrng_unregister(&dev->hwrng);

- mutex_lock(&chaoskey_list_lock);
usb_deregister_dev(interface, &chaoskey_class);

usb_set_intfdata(interface, NULL);
+ mutex_lock(&chaoskey_list_lock);
mutex_lock(&dev->lock);

dev->present = false;

@@ -319,7 +319,7 @@ static int chaoskey_release(struct inode *inode, struct file *file)
bail:
mutex_unlock(&dev->lock);
destruction:
- mutex_lock(&chaoskey_list_lock);
+ mutex_unlock(&chaoskey_list_lock);
usb_dbg(interface, "release success");
return rv;
}

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in chaoskey_release

============================================
WARNING: possible recursive locking detected
6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53-dirty #0 Not tainted
--------------------------------------------
syz.1.64/6626 is trying to acquire lock:
ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x15d/0x2c0 drivers/usb/misc/chaoskey.c:322

but task is already holding lock:

ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x7f/0x2c0 drivers/usb/misc/chaoskey.c:299

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0

----
lock(chaoskey_list_lock);
lock(chaoskey_list_lock);

*** DEADLOCK ***

May be due to missing lock nesting notation

1 lock held by syz.1.64/6626:
#0: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x7f/0x2c0 drivers/usb/misc/chaoskey.c:299

stack backtrace:
CPU: 0 UID: 0 PID: 6626 Comm: syz.1.64 Not tainted 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120

print_deadlock_bug+0x2e3/0x410 kernel/locking/lockdep.c:3037
check_deadlock kernel/locking/lockdep.c:3089 [inline]
validate_chain kernel/locking/lockdep.c:3891 [inline]
__lock_acquire+0x2185/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825

__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752

chaoskey_release+0x15d/0x2c0 drivers/usb/misc/chaoskey.c:322
__fput+0x3f6/0xb60 fs/file_table.c:431
task_work_run+0x14e/0x250 kernel/task_work.c:228
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x24e/0x260 kernel/entry/common.c:218
do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a386fdff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff33961988 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000001f821 RCX: 00007f2a386fdff9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f2a388b7a80 R08: 0000000000000001 R09: 00007fff33961c7f
R10: 00007f2a38580000 R11: 0000000000000246 R12: 0000000000020419
R13: 00007fff33961a90 R14: 0000000000000bea R15: ffffffffffffffff
</TASK>


Tested on:

commit: 4a9fe2a8 dt-bindings: usb: dwc3-imx8mp: add compatible..

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=13c19f67980000

kernel config: https://syzkaller.appspot.com/x/.config?x=4510af5d637450fb
dashboard link: https://syzkaller.appspot.com/bug?extid=1f8ca5ee82576ec01f12
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=10089f9f980000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+1f8ca5...@syzkaller.appspotmail.com
Tested-by: syzbot+1f8ca5...@syzkaller.appspotmail.com

Tested on:

commit: 4a9fe2a8 dt-bindings: usb: dwc3-imx8mp: add compatible..
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=14cac04b980000

kernel config: https://syzkaller.appspot.com/x/.config?x=4510af5d637450fb
dashboard link: https://syzkaller.appspot.com/bug?extid=1f8ca5ee82576ec01f12
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17ec5780580000

Note: testing is done by a robot and is best-effort only.