KASAN: wild-memory-access Write in l2cap_chan_put

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    88bb507a Merge tag 'media/v5.11-3' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=112bab6f500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6e95b9873f64b36c
dashboard link: https://syzkaller.appspot.com/bug?extid=a384548b03ddcbbaf619
userspace arch: i386

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a384548b03ddcbbaf619@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: wild-memory-access in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: wild-memory-access in atomic_fetch_sub_release include/asm-generic/atomic-instrumented.h:220 [inline]
BUG: KASAN: wild-memory-access in __refcount_sub_and_test include/linux/refcount.h:272 [inline]
BUG: KASAN: wild-memory-access in __refcount_dec_and_test include/linux/refcount.h:315 [inline]
BUG: KASAN: wild-memory-access in refcount_dec_and_test include/linux/refcount.h:333 [inline]
BUG: KASAN: wild-memory-access in kref_put include/linux/kref.h:64 [inline]
BUG: KASAN: wild-memory-access in l2cap_chan_put+0x35/0x2e0 net/bluetooth/l2cap_core.c:502
Write of size 4 at addr aaaa00aaaaaaaac2 by task kworker/2:22/10838

CPU: 2 PID: 10838 Comm: kworker/2:22 Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: events l2cap_chan_timeout
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 __kasan_report mm/kasan/report.c:400 [inline]
 kasan_report.cold+0x5f/0xd5 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/generic.c:179 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:185
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_sub_release include/asm-generic/atomic-instrumented.h:220 [inline]
 __refcount_sub_and_test include/linux/refcount.h:272 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 kref_put include/linux/kref.h:64 [inline]
 l2cap_chan_put+0x35/0x2e0 net/bluetooth/l2cap_core.c:502
 l2cap_sock_kill+0xd0/0x240 net/bluetooth/l2cap_sock.c:1217
 l2cap_chan_timeout+0x1cc/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 2 PID: 10838 Comm: kworker/2:22 Tainted: G    B             5.11.0-rc6-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: events l2cap_chan_timeout
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 panic+0x306/0x73d kernel/panic.c:231
 end_report+0x58/0x5e mm/kasan/report.c:100
 __kasan_report mm/kasan/report.c:403 [inline]
 kasan_report.cold+0x67/0xd5 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/generic.c:179 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:185
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_sub_release include/asm-generic/atomic-instrumented.h:220 [inline]
 __refcount_sub_and_test include/linux/refcount.h:272 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 kref_put include/linux/kref.h:64 [inline]
 l2cap_chan_put+0x35/0x2e0 net/bluetooth/l2cap_core.c:502
 l2cap_sock_kill+0xd0/0x240 net/bluetooth/l2cap_sock.c:1217
 l2cap_chan_timeout+0x1cc/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 1 seconds..
ACPI MEMORY or I/O RESET_REG.


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