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From: syzbot <syzbot+ebdb22d461c904fc3cb2@syzkaller.appspotmail.com>
To: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com,
	 horms@kernel.org, kuba@kernel.org, kuniyu@google.com,
	 linux-kernel@vger.kernel.org, ncardwell@google.com,
	netdev@vger.kernel.org,  pabeni@redhat.com,
	syzkaller-bugs@googlegroups.com
Subject: [syzbot] [net?] general protection fault in skb_segment (5)
Date: Fri, 12 Jun 2026 09:19:31 -0700	[thread overview]
Message-ID: <6a2c3193.8812e0fc.3c3fa4.0001.GAE@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    e7aa57247700 Merge tag 'spi-fix-v6.19-rc8' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d69402580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e3161cabe5a361ff
dashboard link: https://syzkaller.appspot.com/bug?extid=ebdb22d461c904fc3cb2
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8243bfd07948/disk-e7aa5724.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/65477df56f75/vmlinux-e7aa5724.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0674f6c7c67d/bzImage-e7aa5724.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ebdb22d461c904fc3cb2@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
CPU: 0 UID: 0 PID: 21038 Comm: syz.4.3937 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:skb_segment+0x2ac4/0x3f80 net/core/skbuff.c:4848
Code: 00 00 00 8b 6c 24 58 81 7c 24 14 ff ff 00 00 0f 85 1c e1 ff ff e8 ec d1 60 f8 48 8b 44 24 20 48 8d 58 70 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 14 09 00 00 8b 1b e9 21 e1 ff ff e8 c3
RSP: 0018:ffffc90000006230 EFLAGS: 00010202
RAX: 000000000000000e RBX: 0000000000000070 RCX: ffff88801bb88000
RDX: 0000000000000100 RSI: ffff888049e648ee RDI: 000000000000ffff
RBP: 0000000000000003 R08: ffff88801bb88000 R09: 0000000000000002
R10: 000000000000a888 R11: 0000000000000100 R12: ffff888049e648e0
R13: 00000000fffffff8 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f1163fb46c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000290000 CR3: 000000002805e000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000404
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 tcp_gso_segment+0x424/0x1a40 net/ipv4/tcp_offload.c:181
 ipv6_gso_segment+0xb80/0x2200 net/ipv6/ip6_offload.c:154
 skb_mac_gso_segment+0x325/0x650 net/core/gso.c:53
 __skb_gso_segment+0x376/0x540 net/core/gso.c:124
 skb_gso_segment include/net/gso.h:83 [inline]
 validate_xmit_skb+0xa13/0x1440 net/core/dev.c:4018
 validate_xmit_skb_list+0x84/0x120 net/core/dev.c:4068
 sch_direct_xmit+0xdf/0x4c0 net/sched/sch_generic.c:332
 qdisc_restart net/sched/sch_generic.c:412 [inline]
 __qdisc_run+0xa8d/0x1540 net/sched/sch_generic.c:420
 qdisc_run include/net/pkt_sched.h:120 [inline]
 __dev_xmit_skb net/core/dev.c:4265 [inline]
 __dev_queue_xmit+0x1bbe/0x3850 net/core/dev.c:4798
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ip6_xmit+0x120f/0x19d0 net/ipv6/ip6_output.c:371
 inet6_csk_xmit+0x4a5/0x750 net/ipv6/inet6_connection_sock.c:120
 __tcp_transmit_skb+0x20b6/0x3ad0 net/ipv4/tcp_output.c:1631
 tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]
 tcp_write_xmit+0x16e8/0x6980 net/ipv4/tcp_output.c:3002
 __tcp_push_pending_frames+0x97/0x380 net/ipv4/tcp_output.c:3185
 tcp_push_pending_frames include/net/tcp.h:2224 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:5896 [inline]
 tcp_rcv_established+0xfee/0x25b0 net/ipv4/tcp_input.c:6476
 tcp_v6_do_rcv+0x8eb/0x1ba0 net/ipv6/tcp_ipv6.c:1607
 tcp_v6_rcv+0x2811/0x3110 net/ipv6/tcp_ipv6.c:1877
 ip6_protocol_deliver_rcu+0xa73/0x1600 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x191/0x370 net/ipv6/ip6_input.c:489
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6152 [inline]
 __netif_receive_skb net/core/dev.c:6265 [inline]
 process_backlog+0x7dd/0x1950 net/core/dev.c:6617
 __napi_poll+0xae/0x340 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0x627/0xf70 net/core/dev.c:7896
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 sk_wait_data+0x20e/0x4d0 net/core/sock.c:3264
 tcp_recvmsg_locked+0xd71/0x35b0 net/ipv4/tcp.c:2776
 tcp_recvmsg+0x213/0x7f0 net/ipv4/tcp.c:2927
 inet6_recvmsg+0x13e/0x6c0 net/ipv6/af_inet6.c:678
 sock_recvmsg_nosec net/socket.c:1078 [inline]
 sock_recvmsg+0x105/0x270 net/socket.c:1100
 __sys_recvfrom+0x240/0x3c0 net/socket.c:2256
 __do_sys_recvfrom net/socket.c:2271 [inline]
 __se_sys_recvfrom net/socket.c:2267 [inline]
 __x64_sys_recvfrom+0xde/0x100 net/socket.c:2267
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1165d9aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1163fb4028 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 00007f1166016180 RCX: 00007f1165d9aeb9
RDX: fffffffffffffd0b RSI: 0000200000000080 RDI: 0000000000000006
RBP: 00007f1165e08c1f R08: 0000000000000000 R09: fffffffffffffd25
R10: 00000000c9100120 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1166016218 R14: 00007f1166016180 R15: 00007f116613fa48
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_segment+0x2ac4/0x3f80 net/core/skbuff.c:4848
Code: 00 00 00 8b 6c 24 58 81 7c 24 14 ff ff 00 00 0f 85 1c e1 ff ff e8 ec d1 60 f8 48 8b 44 24 20 48 8d 58 70 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 14 09 00 00 8b 1b e9 21 e1 ff ff e8 c3
RSP: 0018:ffffc90000006230 EFLAGS: 00010202
RAX: 000000000000000e RBX: 0000000000000070 RCX: ffff88801bb88000
RDX: 0000000000000100 RSI: ffff888049e648ee RDI: 000000000000ffff
RBP: 0000000000000003 R08: ffff88801bb88000 R09: 0000000000000002
R10: 000000000000a888 R11: 0000000000000100 R12: ffff888049e648e0
R13: 00000000fffffff8 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f1163fb46c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000290000 CR3: 000000002805e000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000404
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	8b 6c 24 58          	mov    0x58(%rsp),%ebp
   6:	81 7c 24 14 ff ff 00 	cmpl   $0xffff,0x14(%rsp)
   d:	00
   e:	0f 85 1c e1 ff ff    	jne    0xffffe130
  14:	e8 ec d1 60 f8       	call   0xf860d205
  19:	48 8b 44 24 20       	mov    0x20(%rsp),%rax
  1e:	48 8d 58 70          	lea    0x70(%rax),%rbx
  22:	48 89 d8             	mov    %rbx,%rax
  25:	48 c1 e8 03          	shr    $0x3,%rax
* 29:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 14 09 00 00    	jne    0x94a
  36:	8b 1b                	mov    (%rbx),%ebx
  38:	e9 21 e1 ff ff       	jmp    0xffffe15e
  3d:	e8                   	.byte 0xe8
  3e:	c3                   	ret


---
This report is generated by a bot. It may contain errors.
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                 reply	other threads:[~2026-06-12 16:19 UTC|newest]

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