Subject: [syzbot] general protection fault in bt_accept_unlink (2)

From: syzbot <[email-masked]>
Date: Sat, 06 Mar 2021 23:34:14 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    95b39f07 net: ethernet: mtk-star-emac: fix wrong unmap in ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=13658a5cd00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2d5ba72abae4f14
dashboard link: https://syzkaller.appspot.com/bug?extid=582be673ab4f59f68c5e

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: [email-masked]

general protection fault, probably for non-canonical address 0xf7775c0000001777: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0xbbbb00000000bbb8-0xbbbb00000000bbbf]
CPU: 0 PID: 6057 Comm: kworker/0:6 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
RIP: 0010:__list_del_entry_valid+0x81/0xf0 lib/list_debug.c:51
Code: 0f 84 af d4 08 05 48 b8 22 01 00 00 00 00 ad de 49 39 c4 0f 84 b0 d4 08 05 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 51 49 8b 14 24 48 39 ea 0f 85 67 d4 08 05 49 8d 7d
RSP: 0018:ffffc90002bafb28 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffff8880283424b8 RCX: 0000000000000000
RDX: 1777600000001777 RSI: ffffffff87ebecff RDI: ffff8880283424c0
RBP: ffff8880283424b8 R08: ffffffff8a7af760 R09: ffffffff87f99626
R10: 0000000000000004 R11: 0000000000000005 R12: bbbb00000000bbbb
R13: bb00000000000000 R14: ffff888028341020 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002349848 CR3: 0000000018f19000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:132 [inline]
 list_del_init include/linux/list.h:204 [inline]
 bt_accept_unlink+0x35/0x2f0 net/bluetooth/af_bluetooth.c:187
 l2cap_sock_teardown_cb+0x197/0x660 net/bluetooth/l2cap_sock.c:1542
 l2cap_chan_del+0xbc/0xa80 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x1bc/0xaf0 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x17e/0x2f0 net/bluetooth/l2cap_core.c:436
 process_one_work+0x98d/0x1600 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:294
Modules linked in:
---[ end trace 7d7f7782958a606a ]---
RIP: 0010:__list_del_entry_valid+0x81/0xf0 lib/list_debug.c:51
Code: 0f 84 af d4 08 05 48 b8 22 01 00 00 00 00 ad de 49 39 c4 0f 84 b0 d4 08 05 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 51 49 8b 14 24 48 39 ea 0f 85 67 d4 08 05 49 8d 7d
RSP: 0018:ffffc90002bafb28 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffff8880283424b8 RCX: 0000000000000000
RDX: 1777600000001777 RSI: ffffffff87ebecff RDI: ffff8880283424c0
RBP: ffff8880283424b8 R08: ffffffff8a7af760 R09: ffffffff87f99626
R10: 0000000000000004 R11: 0000000000000005 R12: bbbb00000000bbbb
R13: bb00000000000000 R14: ffff888028341020 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f53667bf000 CR3: 000000002623d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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