linux-kernel - [syzbot] [bluetooth?] KASAN: null-ptr-deref Write in l2cap_sock_resume

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Message-ID: <6798a207.050a0220.ac840.0245.GAE@google.com>
Date: Tue, 28 Jan 2025 01:23:19 -0800
From: syzbot <syzbot+fe280ff30bb95df1577c@...kaller.appspotmail.com>
To: johan.hedberg@...il.com, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bluetooth?] KASAN: null-ptr-deref Write in
 l2cap_sock_resume_cb (3)

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@...kaller.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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