[moderation] [kernel?] WARNING: refcount bug in hdm_disconnect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d0c22de9995b Merge tag 'input-for-v6.15-rc7' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1766f5f4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=201834d558a71127
dashboard link: https://syzkaller.appspot.com/bug?extid=414ecea32de06b16b438
compiler: arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm
CC: [da...@kernel.org gre...@linuxfoundation.org linux-...@vger.kernel.org raf...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/98a89b9f34e4/non_bootable_disk-d0c22de9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/43de0bede099/vmlinux-d0c22de9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d72682f26580/zImage-d0c22de9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+414ece...@syzkaller.appspotmail.com

usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
usb 1-1: string descriptor 0 read error: -71
usb 1-1: USB disconnect, device number 18
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3052 at lib/refcount.c:28 refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28
refcount_t: underflow; use-after-free.
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 UID: 0 PID: 3052 Comm: kworker/1:4 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT
Hardware name: ARM-Versatile Express
Workqueue: usb_hub_wq hub_event
Call trace:
[<802019e4>] (dump_backtrace) from [<80201ae0>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
r7:00000000 r6:828227fc r5:00000000 r4:82257fc8
[<80201ac8>] (show_stack) from [<8021ff7c>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201ac8>] (show_stack) from [<8021ff7c>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<8021ff28>] (dump_stack_lvl) from [<8021ffbc>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
r5:00000000 r4:82a70d4c
[<8021ffa4>] (dump_stack) from [<802025f8>] (panic+0x120/0x374 kernel/panic.c:354)
[<802024d8>] (panic) from [<802619e8>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<802024d8>] (panic) from [<802619e8>] (get_taint+0x0/0x1c kernel/panic.c:238)
r3:8280c604 r2:00000001 r1:8223eb90 r0:82246690
r7:808b4360
[<80261974>] (check_panic_on_warn) from [<80261b4c>] (__warn+0x80/0x188 kernel/panic.c:749)
[<80261acc>] (__warn) from [<80261e3c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:784)
r8:00000009 r7:822af2bc r6:ec841bfc r5:841ce000 r4:00000000
[<80261c58>] (warn_slowpath_fmt) from [<808b4360>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
r10:00000001 r9:829cad04 r8:852e2088 r7:852e1474 r6:8524efb4 r5:852e1400
r4:85392e00
[<808b4224>] (refcount_warn_saturate) from [<81a29188>] (__refcount_sub_and_test include/linux/refcount.h:400 [inline])
[<808b4224>] (refcount_warn_saturate) from [<81a29188>] (__refcount_dec_and_test include/linux/refcount.h:432 [inline])
[<808b4224>] (refcount_warn_saturate) from [<81a29188>] (refcount_dec_and_test include/linux/refcount.h:450 [inline])
[<808b4224>] (refcount_warn_saturate) from [<81a29188>] (kref_put include/linux/kref.h:64 [inline])
[<808b4224>] (refcount_warn_saturate) from [<81a29188>] (kobject_put+0x158/0x1f4 lib/kobject.c:737)
[<81a29030>] (kobject_put) from [<80b1f860>] (put_device+0x18/0x1c drivers/base/core.c:3800)
r7:852e1474 r6:8524efb4 r5:852e1400 r4:8524e800
[<80b1f848>] (put_device) from [<8140c300>] (hdm_disconnect+0x90/0x9c drivers/most/most_usb.c:1129)
[<8140c270>] (hdm_disconnect) from [<80e795cc>] (usb_unbind_interface+0x84/0x2b4 drivers/usb/core/driver.c:458)
r7:852e1474 r6:852e1430 r5:00000000 r4:852e2000
[<80e79548>] (usb_unbind_interface) from [<80b278e8>] (device_remove drivers/base/dd.c:569 [inline])
[<80e79548>] (usb_unbind_interface) from [<80b278e8>] (device_remove+0x64/0x6c drivers/base/dd.c:561)
r10:00000001 r9:852e2088 r8:00000044 r7:852e1474 r6:829cad04 r5:00000000
r4:852e1430
[<80b27884>] (device_remove) from [<80b28dd8>] (__device_release_driver drivers/base/dd.c:1272 [inline])
[<80b27884>] (device_remove) from [<80b28dd8>] (device_release_driver_internal+0x18c/0x200 drivers/base/dd.c:1295)
r5:00000000 r4:852e1430
[<80b28c4c>] (device_release_driver_internal) from [<80b28e64>] (device_release_driver+0x18/0x1c drivers/base/dd.c:1318)
r9:852e2088 r8:830e1040 r7:830e1038 r6:830e100c r5:852e1430 r4:830e1030
[<80b28e4c>] (device_release_driver) from [<80b26f3c>] (bus_remove_device+0xcc/0x120 drivers/base/bus.c:579)
[<80b26e70>] (bus_remove_device) from [<80b21298>] (device_del+0x148/0x38c drivers/base/core.c:3881)
r9:852e2088 r8:841ce000 r7:04208060 r6:00000000 r5:852e1430 r4:852e1474
[<80b21150>] (device_del) from [<80e7701c>] (usb_disable_device+0xd4/0x1e8 drivers/usb/core/message.c:1418)
r10:00000001 r9:00000000 r8:00000000 r7:852e1400 r6:852e2000 r5:85976e08
r4:60000013
[<80e76f48>] (usb_disable_device) from [<80e6bdb0>] (usb_disconnect+0xec/0x29c drivers/usb/core/hub.c:2316)
r9:85393000 r8:852e20cc r7:841eac00 r6:852e2088 r5:852e2000 r4:60000013
[<80e6bcc4>] (usb_disconnect) from [<80e6ea70>] (hub_port_connect drivers/usb/core/hub.c:5371 [inline])
[<80e6bcc4>] (usb_disconnect) from [<80e6ea70>] (hub_port_connect_change drivers/usb/core/hub.c:5671 [inline])
[<80e6bcc4>] (usb_disconnect) from [<80e6ea70>] (port_event drivers/usb/core/hub.c:5831 [inline])
[<80e6bcc4>] (usb_disconnect) from [<80e6ea70>] (hub_event+0xe78/0x194c drivers/usb/core/hub.c:5913)
r10:00000001 r9:00000100 r8:840a9100 r7:852e2000 r6:841ea400 r5:841eae10
r4:00000001
[<80e6dbf8>] (hub_event) from [<802873bc>] (process_one_work+0x1b4/0x4f4 kernel/workqueue.c:3238)
r10:830e1270 r9:83266a05 r8:841ce000 r7:ddde2d80 r6:83266a00 r5:840a9100
r4:84c38500
[<80287208>] (process_one_work) from [<80288004>] (process_scheduled_works kernel/workqueue.c:3319 [inline])
[<80287208>] (process_one_work) from [<80288004>] (worker_thread+0x1fc/0x3d8 kernel/workqueue.c:3400)
r10:61c88647 r9:841ce000 r8:84c3852c r7:82804d40 r6:ddde2d80 r5:ddde2da0
r4:84c38500
[<80287e08>] (worker_thread) from [<8028f07c>] (kthread+0x12c/0x280 kernel/kthread.c:464)
r10:00000000 r9:84c38500 r8:80287e08 r7:ec83de60 r6:84c38580 r5:841ce000
r4:00000001
[<8028ef50>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xec841fb0 to 0xec841ff8)
1fa0: 00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8028ef50
r4:84c36b80
Rebooting in 86400 seconds..


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