syzbot


general protection fault in skb_unlink

Status: upstream: reported C repro on 2019/11/24 09:40
Reported-by: syzbot+3d9aa25f2dd3b690ee21@syzkaller.appspotmail.com
First crash: 1161d, last: 494d

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 142d 1703d 23/24 upstream: reported C repro on 2018/05/31 08:16
linux-4.14 general protection fault in skb_unlink C done error 2 981d 1161d 0/1 upstream: reported C repro on 2019/11/24 07:04

Sample crash report:
audit: type=1400 audit(1574584202.698:41): avc:  denied  { prog_run } for  pid=7631 comm="syz-executor501" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1
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
CPU: 1 PID: 7635 Comm: syz-executor501 Not tainted 4.19.85-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline]
RIP: 0010:__skb_unlink include/linux/skbuff.h:1900 [inline]
RIP: 0010:skb_unlink+0xc4/0x160 net/core/skbuff.c:2945
Code: 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 ff
RSP: 0018:ffff88809ee67908 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: ffff8880962d3c80 RCX: ffffffff81531da8
RDX: 0000000000000001 RSI: 0000000000000282 RDI: 0000000000000008
RBP: ffff88809ee67930 R08: 1ffff110131aab3c R09: ffffed10131aab3d
R10: ffffed10131aab3c R11: ffff888098d559e3 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888098d559e0 R15: ffff88809ee679d8
FS:  00007ff7a8648700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e4628f21b0 CR3: 00000000a55b5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kcm_recvmsg+0x462/0x560 net/kcm/kcmsock.c:1160
 sock_recvmsg_nosec+0x89/0xb0 net/socket.c:795
 ___sys_recvmsg+0x271/0x580 net/socket.c:2277
 __sys_recvmmsg+0x27e/0x790 net/socket.c:2389
 do_sys_recvmmsg net/socket.c:2465 [inline]
 do_sys_recvmmsg+0x181/0x1a0 net/socket.c:2454
 __do_sys_recvmmsg net/socket.c:2483 [inline]
 __se_sys_recvmmsg net/socket.c:2479 [inline]
 __x64_sys_recvmmsg+0xbe/0x150 net/socket.c:2479
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x448b29
Code: e8 0c 1b 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 0c fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff7a8647ce8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000006dfc48 RCX: 0000000000448b29
RDX: 0400000000000310 RSI: 0000000020003540 RDI: 0000000000000005
RBP: 00000000006dfc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dfc4c
R13: 00007ffc3828db3f R14: 00007ff7a86489c0 R15: 000000000000002d
Modules linked in:
---[ end trace 5cc8695cf11eea5f ]---
RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline]
RIP: 0010:__skb_unlink include/linux/skbuff.h:1900 [inline]
RIP: 0010:skb_unlink+0xc4/0x160 net/core/skbuff.c:2945
Code: 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 ff
RSP: 0018:ffff88809ee67908 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: ffff8880962d3c80 RCX: ffffffff81531da8
RDX: 0000000000000001 RSI: 0000000000000282 RDI: 0000000000000008
RBP: ffff88809ee67930 R08: 1ffff110131aab3c R09: ffffed10131aab3d
R10: ffffed10131aab3c R11: ffff888098d559e3 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888098d559e0 R15: ffff88809ee679d8
FS:  00007ff7a8648700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e4628f21b0 CR3: 00000000a55b5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-linux-4-19 2019/11/24 08:39 linux-4.19.y c63ee2939dc1 598ca6c8 .config console log report syz C
* Struck through repros no longer work on HEAD.