[syzbot] [kernel?] WARNING in class_register

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a6d9e3034536 Add linux-next specific files for 20230330
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1496edcdc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=aceb117f7924508e
dashboard link: https://syzkaller.appspot.com/bug?extid=ca3d9f693dfa69f61371
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f57859c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=167cc501c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ec1f900ea929/disk-a6d9e303.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fabbf89c0d22/vmlinux-a6d9e303.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1ed05d6192fa/bzImage-a6d9e303.xz

The issue was bisected to:

commit dcfbb67e48a2becfce7990386e985b9c45098ee5
Author: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Date: Fri Mar 24 10:01:31 2023 +0000

driver core: class: use lock_class_key already present in struct subsys_private

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10190b49c80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=12190b49c80000
console output: https://syzkaller.appspot.com/x/log.txt?x=14190b49c80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ca3d9f...@syzkaller.appspotmail.com
Fixes: dcfbb67e48a2 ("driver core: class: use lock_class_key already present in struct subsys_private")

plantronics 0003:047F:7FFF.0035: No inputs registered, leaving
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7 at kernel/locking/lockdep.c:1232 lockdep_register_key+0x2a4/0x410 kernel/locking/lockdep.c:1232
Modules linked in:
CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.3.0-rc4-next-20230330-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:lockdep_register_key+0x2a4/0x410 kernel/locking/lockdep.c:1232
Code: 5c 41 5d 41 5e 41 5f c3 48 89 d8 48 c1 e8 03 80 3c 10 00 0f 85 fb 00 00 00 48 8b 1b 48 85 db 0f 84 fb fe ff ff 48 39 dd 75 de <0f> 0b eb 87 9c 58 f6 c4 02 0f 84 0f fe ff ff e8 78 c3 aa 02 85 c0
RSP: 0018:ffffc900000c6908 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff888028470b60 RCX: 1ffffffff1cf16e6
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900000c6930
RBP: ffff888028470b60 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52000018d26 R11: 0000000000094001 R12: 0000000000000cf8
R13: 1ffff92000018d22 R14: ffffffff9167f900 R15: 0000000000000a03
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001040 CR3: 0000000027dfb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
class_register+0xed/0x530 drivers/base/class.c:172
class_create+0x99/0x100 drivers/base/class.c:249
init_usb_class drivers/usb/core/file.c:91 [inline]
usb_register_dev+0x4e7/0x860 drivers/usb/core/file.c:179
hiddev_connect+0x3bd/0x610 drivers/hid/usbhid/hiddev.c:903
hid_connect+0x271/0x18c0 drivers/hid/hid-core.c:2192
hid_hw_start drivers/hid/hid-core.c:2302 [inline]
hid_hw_start+0xa6/0x130 drivers/hid/hid-core.c:2293
plantronics_probe+0x304/0x400 drivers/hid/hid-plantronics.c:191
hid_device_probe+0x2aa/0x3d0 drivers/hid/hid-core.c:2633
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3616
hid_add_device+0x377/0xa60 drivers/hid/hid-core.c:2785
usbhid_probe+0xc43/0x1100 drivers/hid/usbhid/hid-core.c:1429
usb_probe_interface+0x30f/0x960 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3616
usb_set_configuration+0x10ee/0x1af0 drivers/usb/core/message.c:2171
usb_generic_driver_probe+0xcf/0x130 drivers/usb/core/generic.c:238
usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3616
usb_new_device+0xcb2/0x19d0 drivers/usb/core/hub.c:2575
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
port_event drivers/usb/core/hub.c:5711 [inline]
hub_event+0x2d9e/0x4e40 drivers/usb/core/hub.c:5793
process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
kthread+0x33e/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Hillf Danton]

On 01 Apr 2023 13:39:42 -0700

> HEAD commit: a6d9e3034536 Add linux-next specific files for 20230330
> git tree: linux-next

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=167cc501c80000

Add lockdep_unregister_key() in class_register() and class_release().

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git a6d9e3034536

--- x/drivers/base/class.c
+++ y/drivers/base/class.c
@@ -61,6 +61,7 @@ static void class_release(struct kobject
pr_debug("class '%s' does not have a release() function, "
"be careful\n", class->name);

+ lockdep_unregister_key(&cp->lock_key);
kfree(cp);
}

@@ -173,6 +174,7 @@ int class_register(struct class *cls)
__mutex_init(&cp->mutex, "subsys mutex", key);
error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
if (error) {
+ lockdep_unregister_key(key);
kfree(cp);
return error;
}
@@ -200,6 +202,7 @@ int class_register(struct class *cls)
return 0;

err_out:
+ lockdep_unregister_key(key);
kfree(cp);
cls->p = NULL;
return error;
--

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+ca3d9f...@syzkaller.appspotmail.com

Tested on:

commit: a6d9e303 Add linux-next specific files for 20230330
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=129b3ea5c80000

kernel config: https://syzkaller.appspot.com/x/.config?x=aceb117f7924508e
dashboard link: https://syzkaller.appspot.com/bug?extid=ca3d9f693dfa69f61371
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=16340cedc80000

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

[Greg KH]

Should already be fixed by:
https://lore.kernel.org/all/2023040126-blandness-duckling-bd55@gregkh/
which was a different syzbot-reported issue with this same commit.

thanks,

greg k-h

[Dmitry Vyukov]

Let's tell syzbot so that it reports similar bugs in future:

#syz fix:
driver core: class : fix slab-use-after-free Read in class_register()

[syzbot]

This bug is marked as fixed by commit:

driver core: class : fix slab-use-after-free Read in class_register()

But I can't find it in the tested trees[1] for more than 90 days.
Is it a correct commit? Please update it by replying:

#syz fix: exact-commit-title

Until then the bug is still considered open and new crashes with
the same signature are ignored.

Kernel: Linux
Dashboard link: https://syzkaller.appspot.com/bug?extid=ca3d9f693dfa69f61371

---
[1] I expect the commit to be present in:

1. for-kernelci branch of
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git

2. master branch of
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git

3. master branch of
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git

4. main branch of
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git

The full list of 10 trees can be found at
https://syzkaller.appspot.com/upstream/repos

[syzbot]

The full list of 9 trees can be found at
https://syzkaller.appspot.com/upstream/repos

[syzbot]

[Aleksandr Nogikh]

> This bug is marked as fixed by commit:
> driver core: class : fix slab-use-after-free Read in class_register()

> But I can't find it in the tested trees[1] for more than 90 days.

#syz fix: driver core: class: fix slab-use-after-free Read in class_register()