[syzbot] [bluetooth?] KASAN: null-ptr-deref Write in l2cap_sock_resume_cb (3)

syzbot
2025-01-28T09:23:19Z

Hello,

syzbot found the following issue on:

HEAD commit: 8883957b3c9d Merge tag 'fsnotify_hsm_for_v6.14-rc1' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13862564580000
kernel config: https://syzkaller.appspot.com/x/.config?x=77593a73383cac88
dashboard link: https://syzkaller.appspot.com/bug?extid=fe280ff30bb95df1577c
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-8883957b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/df6d282e0e7d/vmlinux-8883957b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9a6f61832d52/bzImage-8883957b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe280ff30bb95df1577c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_write include/linux/instrumented.h:82 [inline]
BUG: KASAN: null-ptr-deref in clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline]
BUG: KASAN: null-ptr-deref in l2cap_sock_resume_cb+0xd0/0x130 net/bluetooth/l2cap_sock.c:1699
Write of size 8 at addr 0000000000000568 by task kworker/u33:4/5957

CPU: 3 UID: 0 PID: 5957 Comm: kworker/u33:4 Not tainted 6.13.0-syzkaller-05154-g8883957b3c9d #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: hci3 hci_rx_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
kasan_report+0xd9/0x110 mm/kasan/report.c:602
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
instrument_atomic_write include/linux/instrumented.h:82 [inline]
clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline]
l2cap_sock_resume_cb+0xd0/0x130 net/bluetooth/l2cap_sock.c:1699
l2cap_security_cfm+0x795/0x11d0 net/bluetooth/l2cap_core.c:7346
hci_security_cfm include/net/bluetooth/hci_core.h:2088 [inline]
hci_encrypt_cfm+0x1f2/0x7d0 include/net/bluetooth/hci_core.h:2136
hci_encrypt_change_evt+0x3f3/0x1130 net/bluetooth/hci_event.c:3655
hci_event_func net/bluetooth/hci_event.c:7473 [inline]
hci_event_packet+0x9eb/0x1190 net/bluetooth/hci_event.c:7525
hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4015
process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
==================================================================

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