syzbot


general protection fault in skb_unlink

Status: upstream: reported C repro on 2019/11/24 07:04
Reported-by: syzbot+6678cfc7fcb16d651fda@syzkaller.appspotmail.com
First crash: 1169d, last: 989d

Cause bisection: introduced by (bisect log) :
commit 2de50e9674fc4ca3c6174b04477f69eb26b4ee31
Author: Russell Currey <ruscur@russell.cc>
Date: Mon Feb 8 04:08:20 2016 +0000

  powerpc/powernv: Remove support for p5ioc2

Crash: BUG: spinlock lockup suspected in nf_conntrack_lock (log)
Repro: C syz .config

Fix bisection: failed (bisect log)
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in skb_unlink C done error 8 150d 1711d 23/24 upstream: reported C repro on 2018/05/31 08:16
linux-4.19 general protection fault in skb_unlink C done error 1 501d 1169d 0/1 upstream: reported C repro on 2019/11/24 09:40
Last patch testing requests:
Created Duration User Patch Repo Result
2022/12/13 09:31 10m retest repro linux-4.14.y report log
2022/08/28 22:27 11m retest repro linux-4.14.y report log

Sample crash report:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7020 Comm: syz-executor037 Not tainted 4.14.155-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809c7ae0c0 task.stack: ffff888078968000
RIP: 0010:__write_once_size include/linux/compiler.h:210 [inline]
RIP: 0010:__skb_unlink include/linux/skbuff.h:1886 [inline]
RIP: 0010:skb_unlink+0xc4/0x160 net/core/skbuff.c:2942
RSP: 0018:ffff88807896f9b0 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: ffff888091054a00 RCX: 00000000f13abcde
RDX: 0000000000000001 RSI: 0000000000000282 RDI: 0000000000000008
RBP: ffff88807896f9d8 R08: 0000000000006a3c R09: ffffffff88cb97a0
R10: ffff88809c7ae968 R11: ffff88809c7ae0c0 R12: ffff888091054b40
R13: 0000000000000000 R14: ffff8880a4f6b4a0 R15: ffff88807896fa58
FS:  00007f9a3bbed700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000209ff000 CR3: 000000009f97a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kcm_recvmsg+0x3a2/0x480 net/kcm/kcmsock.c:1160
 sock_recvmsg_nosec+0x89/0xb0 net/socket.c:819
 ___sys_recvmsg+0x21f/0x4d0 net/socket.c:2221
 __sys_recvmmsg+0x226/0x6b0 net/socket.c:2329
 SYSC_recvmmsg net/socket.c:2405 [inline]
 SyS_recvmmsg+0x125/0x140 net/socket.c:2394
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x446ba9
RSP: 002b:00007f9a3bbecd98 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 0000000000446ba9
RDX: 0400000000000310 RSI: 0000000020003540 RDI: 0000000000000005
RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00000000002b0095 R14: 0000a50000000000 R15: 0000000300000018
Code: 00 00 00 49 8d 7d 08 4c 8b 63 08 48 b8 00 00 00 00 00 fc ff df 48 c7 43 08 00 00 00 00 48 89 fa 48 c7 03 00 00 00 00 48 c1 ea 03 <80> 3c 02 00 75 58 4c 89 e2 4d 89 65 08 48 b8 00 00 00 00 00 fc 
RIP: __write_once_size include/linux/compiler.h:210 [inline] RSP: ffff88807896f9b0
RIP: __skb_unlink include/linux/skbuff.h:1886 [inline] RSP: ffff88807896f9b0
RIP: skb_unlink+0xc4/0x160 net/core/skbuff.c:2942 RSP: ffff88807896f9b0
---[ end trace e99ec447687e2d78 ]---

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-linux-4-14 2019/11/24 07:46 linux-4.14.y f56f3d0e65ad 598ca6c8 .config console log report syz C
ci2-linux-4-14 2019/11/24 06:03 linux-4.14.y f56f3d0e65ad 598ca6c8 .config console log report
* Struck through repros no longer work on HEAD.