Message-ID: <0000000000005426680605eb0b9f@google.com>
Date:   Thu, 21 Sep 2023 21:28:45 -0700
From:   syzbot <syzbot+c99d835ff081ca30f986@...kaller.appspotmail.com>
To:     andrew@...nix.com, davem@...emloft.net, edumazet@...gle.com,
        jhs@...atatu.com, jiri@...nulli.us, kuba@...nel.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        pabeni@...hat.com, syzkaller-bugs@...glegroups.com,
        xiyou.wangcong@...il.com
Subject: [syzbot] [net?] WARNING in skb_warn_bad_offload (4)

Hello,

syzbot found the following issue on:

HEAD commit:    25041a4c02c7 Merge tag 'net-6.4-rc6' of git://git.kernel.o..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=120a16dd280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c980bfe8b399968
dashboard link: https://syzkaller.appspot.com/bug?extid=c99d835ff081ca30f986
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15808795280000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17de0463280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2e8d60d638d1/disk-25041a4c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a4a1a9057ac2/vmlinux-25041a4c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/66efccc5227d/bzImage-25041a4c.xz

The issue was bisected to:

commit 860b7f27b8f78564ca5a2f607e0820b2d352a562
Author: Andrew Melnychenko <andrew@...nix.com>
Date:   Wed Dec 7 11:35:57 2022 +0000

    linux/virtio_net.h: Support USO offload in vnet header.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12544729a80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=11544729a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=16544729a80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c99d835ff081ca30f986@...kaller.appspotmail.com
Fixes: 860b7f27b8f7 ("linux/virtio_net.h: Support USO offload in vnet header.")

skb linear:   000000f0: 00 00 00 00 00 00 65 72 73 70 61 6e 30 00 00 00
skb linear:   00000100: 00 00 00 00 00 00 05 00 00 00 00 00 00 00 00 00
skb linear:   00000110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   00000120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
------------[ cut here ]------------
erspan0: caps=(0x0000000000006869, 0x0000000000000000)
WARNING: CPU: 0 PID: 5002 at net/core/dev.c:3228 skb_warn_bad_offload+0x119/0x230 net/core/dev.c:3228
Modules linked in:
CPU: 0 PID: 5002 Comm: syz-executor416 Not tainted 6.4.0-rc5-syzkaller-00133-g25041a4c02c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:skb_warn_bad_offload+0x119/0x230 net/core/dev.c:3228
Code: 70 03 00 00 e8 18 96 76 f9 4c 8d a5 f0 00 00 00 e8 0c 96 76 f9 4c 89 e9 4c 89 e2 4c 89 f6 48 c7 c7 00 36 5e 8b e8 d7 51 3e f9 <0f> 0b 5b 5d 41 5c 41 5d 41 5e e9 e8 95 76 f9 e8 e3 95 76 f9 48 89
RSP: 0018:ffffc90003a5f6b0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88807b7ac000 RCX: 0000000000000000
RDX: ffff88802176bb80 RSI: ffffffff814c03b7 RDI: 0000000000000001
RBP: ffff88802c452000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802c4520f0
R13: ffff88807b7ac370 R14: ffff88802c452000 R15: 000000000000000e
FS:  0000555557281300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 00000000758bf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __skb_gso_segment+0x3eb/0x6e0 net/core/dev.c:3404
 skb_gso_segment include/linux/netdevice.h:4862 [inline]
 validate_xmit_skb+0x69c/0xef0 net/core/dev.c:3659
 validate_xmit_skb_list+0xc0/0x130 net/core/dev.c:3709
 sch_direct_xmit+0x3d5/0xc30 net/sched/sch_generic.c:327
 __dev_xmit_skb net/core/dev.c:3805 [inline]
 __dev_queue_xmit+0x14d6/0x3b10 net/core/dev.c:4210
 dev_queue_xmit include/linux/netdevice.h:3088 [inline]
 packet_xmit+0x260/0x390 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3081 [inline]
 packet_sendmsg+0x347f/0x5030 net/packet/af_packet.c:3113
 sock_sendmsg_nosec net/socket.c:724 [inline]
 sock_sendmsg+0xde/0x190 net/socket.c:747
 __sys_sendto+0x23a/0x340 net/socket.c:2144
 __do_sys_sendto net/socket.c:2156 [inline]
 __se_sys_sendto net/socket.c:2152 [inline]
 __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2152
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0c72415529
Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe61bb6468 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ffe61bb6488 RCX: 00007f0c72415529
RDX: 0000000000002378 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 00000000000002ff
R10: 0000000004000002 R11: 0000000000000246 R12: 00007ffe61bb6490
R13: 00007ffe61bb64b0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
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#syz undup

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