syzbot


WARNING in gre_tap_xmit

Status: fixed on 2024/05/24 17:37
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+5fc5f19392dd9b9b1707@syzkaller.appspotmail.com
Fix commit: 39a055e607cb net l2tp: drop flow hash on forward
First crash: 57d, last: 56d
Fix bisection: fixed by (bisect log) :
commit 39a055e607cb80688a26b68a53deaeea5c02c6e9
Author: David Bauer <mail@david-bauer.net>
Date: Wed Apr 24 17:11:10 2024 +0000

  net l2tp: drop flow hash on forward

  
Bug presence (1)
Date Name Commit Repro Result
2024/04/19 upstream (ToT) 2d412262ccfd C [report] WARNING in gre_tap_xmit
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in gre_tap_xmit (2) net C done 67 32d 57d 26/27 fixed on 2024/05/22 23:26
upstream WARNING in gre_tap_xmit net C done 13 57d 57d 0/27 closed as invalid on 2024/04/19 06:38

Sample crash report:
netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
netlink: 'syz-executor355': attribute type 10 has an invalid length.
bond0: (slave gretap0): Enslaving as an active interface with an up link
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3542 at include/linux/skbuff.h:2641 pskb_network_may_pull include/linux/skbuff.h:2967 [inline]
WARNING: CPU: 1 PID: 3542 at include/linux/skbuff.h:2641 pskb_inet_may_pull include/net/ip_tunnels.h:351 [inline]
WARNING: CPU: 1 PID: 3542 at include/linux/skbuff.h:2641 gre_tap_xmit+0x501/0x6e0 net/ipv4/ip_gre.c:737
Modules linked in:
CPU: 1 PID: 3542 Comm: syz-executor355 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:pskb_may_pull include/linux/skbuff.h:2641 [inline]
RIP: 0010:pskb_network_may_pull include/linux/skbuff.h:2967 [inline]
RIP: 0010:pskb_inet_may_pull include/net/ip_tunnels.h:351 [inline]
RIP: 0010:gre_tap_xmit+0x501/0x6e0 net/ipv4/ip_gre.c:737
Code: b6 8d 09 0d 00 00 4c 89 ef 48 89 ee 48 89 da e8 25 b6 fb ff 31 c0 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 5f a1 60 f8 <0f> 0b e9 04 fc ff ff 44 89 e7 89 ee e8 ae a2 60 f8 41 39 ec 48 bd
RSP: 0018:ffffc900039fee90 EFLAGS: 00010293
RAX: ffffffff8929ee01 RBX: ffff888070cc75d8 RCX: ffff8880244e0000
RDX: 0000000000000000 RSI: 00000000ffffffb6 RDI: 0000000000000000
RBP: 00000000ffffffb6 R08: ffffffff8929e9fe R09: fffffbfff1ce6eee
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff888070cc7500 R14: ffff888078f5a000 R15: dffffc0000000000
FS:  0000555557053380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020010000 CR3: 000000007974b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __netdev_start_xmit include/linux/netdevice.h:4853 [inline]
 netdev_start_xmit include/linux/netdevice.h:4867 [inline]
 xmit_one net/core/dev.c:3627 [inline]
 dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3643
 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3854 [inline]
 __dev_queue_xmit+0x1ace/0x3cf0 net/core/dev.c:4259
 bond_start_xmit+0x134b/0x1d50 drivers/net/bonding/bond_main.c:5482
 __netdev_start_xmit include/linux/netdevice.h:4853 [inline]
 netdev_start_xmit include/linux/netdevice.h:4867 [inline]
 xmit_one net/core/dev.c:3627 [inline]
 dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3643
 __dev_queue_xmit+0x1bb1/0x3cf0 net/core/dev.c:4293
 packet_snd net/packet/af_packet.c:3077 [inline]
 packet_sendmsg+0x4775/0x61a0 net/packet/af_packet.c:3108
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514
 ___sys_sendmsg net/socket.c:2568 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2597
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4ace735c09
Code: 48 83 c4 28 c3 e8 d7 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffee638f638 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4ace7833d3 RCX: 00007f4ace735c09
RDX: 00000000200400c4 RSI: 0000000020000180 RDI: 0000000000000004
RBP: 00007ffee638f660 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000004 R11: 0000000000000246 R12: 00007ffee638f670
R13: 00007f4ace783004 R14: 00007ffee638f65c R15: 0000000000000003
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/19 14:28 linux-6.1.y 6741e066ec76 af24b050 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf WARNING in gre_tap_xmit
2024/04/20 02:49 linux-6.1.y 6741e066ec76 af24b050 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf WARNING in gre_tap_xmit
* Struck through repros no longer work on HEAD.