[syzbot] general protection fault in kernel_accept (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d40ce48cb3a6 Merge branch 'af_unix-replace-unix_table_lock..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14b86465b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7cc851c2debde333
dashboard link: https://syzkaller.appspot.com/bug?extid=03655f787f231d1b7b6c
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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+03655f...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000072: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000390-0x0000000000000397]
CPU: 0 PID: 15597 Comm: kworker/u4:6 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: tipc_rcv tipc_topsrv_accept
RIP: 0010:kernel_accept+0x56/0x350 net/socket.c:3417
Code: c1 ea 03 80 3c 02 00 0f 85 90 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 18 49 8d bc 24 94 03 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 50
RSP: 0018:ffffc90002fdfc30 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffffc90002fdfca8 RCX: 0000000000000000
RDX: 0000000000000072 RSI: ffffffff87211fca RDI: 0000000000000394
RBP: ffff888035524800 R08: 0000000000000001 R09: ffffffff8ff7bb3f
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000800 R14: ffff88802668f770 R15: ffff88802668f2c0
FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f41e78fc1b8 CR3: 0000000021d55000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Modules linked in:
---[ end trace d8fc85c5be0bfa88 ]---
RIP: 0010:kernel_accept+0x56/0x350 net/socket.c:3417
Code: c1 ea 03 80 3c 02 00 0f 85 90 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 18 49 8d bc 24 94 03 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 50
RSP: 0018:ffffc90002fdfc30 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffffc90002fdfca8 RCX: 0000000000000000
RDX: 0000000000000072 RSI: ffffffff87211fca RDI: 0000000000000394
RBP: ffff888035524800 R08: 0000000000000001 R09: ffffffff8ff7bb3f
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000800 R14: ffff88802668f770 R15: ffff88802668f2c0
FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93092d2000 CR3: 000000001bf56000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: c1 ea 03 shr $0x3,%edx
3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
7: 0f 85 90 02 00 00 jne 0x29d
d: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
14: fc ff df
17: 4c 8b 65 18 mov 0x18(%rbp),%r12
1b: 49 8d bc 24 94 03 00 lea 0x394(%r12),%rdi
22: 00
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx <-- trapping instruction
2e: 48 89 f8 mov %rdi,%rax
31: 83 e0 07 and $0x7,%eax
34: 83 c0 01 add $0x1,%eax
37: 38 d0 cmp %dl,%al
39: 7c 08 jl 0x43
3b: 84 d2 test %dl,%dl
3d: 0f .byte 0xf
3e: 85 .byte 0x85
3f: 50 push %rax


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.