WARNING in ipgre_xmit (2)

Status: upstream: reported C repro on 2026/08/02 18:48
Subsystems: net
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+f16c1b285c9f63994eec@syzkaller.appspotmail.com
First crash: 51d, last: 13h37m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
267b2c63 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in ipgre_xmit (2) 2026/07/31 01:50 2026/07/31 01:50 2026/07/31 01:58 aaffb173
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH net v3] xsk: set network header on skb at generic transmit 4 (4) 2026/09/07 12:01
[PATCH net v2] xsk: set network header on skb at generic transmit 6 (6) 2026/09/04 04:10
[PATCH net] xsk: set network header on skb at generic transmit 3 (3) 2026/09/01 07:51
[syzbot] [net?] WARNING in ipgre_xmit (2) 7 (12) 2026/08/12 12:52
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 WARNING in ipgre_xmit -1 syz, C 2 18d 36d 0/1 premoderation: reported C repro on 2026/08/13 02:23
upstream WARNING in ipgre_xmit net -1 syz, C done 9916 1552d 1569d 22/29 fixed on 2023/02/24 13:51
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/09/18 06:37 13m retest repro upstream report job log log
2026/08/12 12:52 39m kerneljasonxing@gmail.com patch upstream error job log
2026/08/09 06:04 8m kerneljasonxing@gmail.com patch upstream error
2026/08/09 01:59 1h17m kerneljasonxing@gmail.com patch upstream error
▶ ▼ Cause bisection attempts (2)
Created Duration User Patch Repo Result
2026/09/02 03:20 0m bisect upstream error
2026/08/16 23:04 0m bisect net error

Sample crash report:
------------[ cut here ]------------
len > ((int)(~0U >> 1))
WARNING: ./include/linux/skbuff.h:2864 at pskb_may_pull_reason include/linux/skbuff.h:2864 [inline], CPU#1: syz-executor147/5638
WARNING: ./include/linux/skbuff.h:2864 at pskb_network_may_pull_reason include/linux/skbuff.h:3265 [inline], CPU#1: syz-executor147/5638
WARNING: ./include/linux/skbuff.h:2864 at pskb_inet_may_pull_reason include/net/ip_tunnels.h:481 [inline], CPU#1: syz-executor147/5638
WARNING: ./include/linux/skbuff.h:2864 at pskb_inet_may_pull include/net/ip_tunnels.h:486 [inline], CPU#1: syz-executor147/5638
WARNING: ./include/linux/skbuff.h:2864 at ipgre_xmit+0x958/0xcd0 net/ipv4/ip_gre.c:658, CPU#1: syz-executor147/5638
Modules linked in:
CPU: 1 UID: 0 PID: 5638 Comm: syz-executor147 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pskb_may_pull_reason include/linux/skbuff.h:2864 [inline]
RIP: 0010:pskb_network_may_pull_reason include/linux/skbuff.h:3265 [inline]
RIP: 0010:pskb_inet_may_pull_reason include/net/ip_tunnels.h:481 [inline]
RIP: 0010:pskb_inet_may_pull include/net/ip_tunnels.h:486 [inline]
RIP: 0010:ipgre_xmit+0x958/0xcd0 net/ipv4/ip_gre.c:658
Code: 48 3b 84 24 80 00 00 00 0f 85 3b 01 00 00 31 c0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 3f 1a 78 01 cc e8 09 f5 6a f7 90 <0f> 0b 90 e9 08 f8 ff ff 44 89 ff 44 89 e6 e8 b5 f6 6a f7 45 39 e7
RSP: 0018:ffffc900039af5e0 EFLAGS: 00010293
RAX: ffffffff8a5c1d67 RBX: 0000000000000000 RCX: ffff888079535d00
RDX: 0000000000000000 RSI: 00000000ffffff40 RDI: 0000000000000000
RBP: ffffc900039af6b0 R08: ffff888079535d00 R09: 0000000000000002
R10: 0000000000004888 R11: ffffffff8a5c1410 R12: ffff88807ecbc000
R13: dffffc0000000000 R14: ffff88807b7f2780 R15: 00000000ffffff40
FS:  0000555590a0a400(0000) GS:ffff88812504b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055704428ded0 CR3: 00000000788f2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 __dev_direct_xmit+0x4b6/0x730 net/core/dev.c:4942
 __xsk_generic_xmit net/xdp/xsk.c:1253 [inline]
 xsk_generic_xmit+0x2759/0x47b0 net/xdp/xsk.c:1309
 __xsk_sendmsg net/xdp/xsk.c:1363 [inline]
 xsk_sendmsg+0x482/0x810 net/xdp/xsk.c:1373
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2684
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc137b1b409
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffc9ef46d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc137b1b409
RDX: 0000000000000040 RSI: 0000200000000700 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000080000000 R09: 0000000080000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
 </TASK>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/04 17:00 upstream 848acc8ffe1b d4abbeac .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in ipgre_xmit
2026/08/16 05:59 upstream 3eb40771c00a 746171ee .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ipgre_xmit
2026/08/04 22:24 net cf6f8b29befb d4abbeac .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in ipgre_xmit
2026/08/15 07:49 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 21d6ac051080 746171ee .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in ipgre_xmit
2026/08/20 10:55 upstream 98f21c54f995 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ipgre_xmit
2026/08/04 19:28 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ipgre_xmit
2026/08/04 19:28 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ipgre_xmit
2026/08/04 15:22 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in ipgre_xmit
2026/08/04 15:22 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in ipgre_xmit
2026/08/25 19:39 upstream 818bebeb63dd a9a1fc32 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ipgre_xmit
2026/08/06 16:17 upstream 0d8395707651 cc56899a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in ipgre_xmit
2026/08/06 16:16 upstream 0d8395707651 cc56899a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in ipgre_xmit
2026/08/04 15:03 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in ipgre_xmit
2026/08/04 15:03 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in ipgre_xmit
2026/07/29 18:43 upstream fc02acf6ac0c b63596d1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in ipgre_xmit
2026/09/04 06:02 net adf50c47a47f 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in ipgre_xmit
2026/08/04 22:21 net cf6f8b29befb d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in ipgre_xmit
* Struck through repros no longer work on HEAD.