syzbot


kernel BUG in ip6gre_header (6)

Status: fixed on 2026/01/26 05:07
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+43a2ebcf2a64b1102d64@syzkaller.appspotmail.com
Fix commit: db5b4e39c4e6 ip6_gre: make ip6gre_header() robust
First crash: 62d, last: 32d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH net] ip6_gre: make ip6gre_header() robust 1 (1) 2025/12/11 17:35
[syzbot] [net?] kernel BUG in ip6gre_header (6) 0 (1) 2025/12/11 17:32
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 kernel BUG at net/core/skbuff.c:LINE! -1 C unreliable 494 1250d 2469d 0/1 upstream: reported C repro on 2019/04/27 20:12
upstream kernel BUG in ip6gre_header (2) net -1 C 2 840d 854d 25/29 fixed on 2024/01/20 21:18
upstream kernel BUG in ip6gre_header net -1 C 5 890d 961d 23/29 fixed on 2023/09/28 17:51
upstream kernel BUG in ip6gre_header (5) net -1 1 542d 542d 0/29 closed as invalid on 2024/08/29 14:58
upstream kernel BUG in ip6gre_header (3) net -1 1 724d 724d 0/29 closed as invalid on 2024/03/01 17:31
upstream kernel BUG in ip6gre_header (4) net -1 1 632d 632d 0/29 closed as invalid on 2024/06/03 15:58
upstream kernel BUG in llc_sap_action_send_xid_c net -1 C error 61 1543d 1756d 20/29 fixed on 2021/11/10 00:50
upstream kernel BUG in pskb_expand_head net -1 C done 1600 1086d 1537d 22/29 fixed on 2023/02/25 08:02
linux-6.1 kernel BUG in ip6gre_header origin:upstream -1 C error 1 505d 961d 0/3 upstream: reported C repro on 2023/06/14 11:11
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/12/11 14:13 21m edumazet@google.com patch upstream OK log

Sample crash report:
skbuff: skb_under_panic: text:ffffffff8a1d69a8 len:136 put:40 head:ffff888059bc7000 data:ffff888059bc6fe8 tail:0x70 end:0x6c0 dev:team0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:213!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: mld mld_ifc_work
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
Code: c7 e0 1a 6f 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 8e 94 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001b7280 EFLAGS: 00010282
RAX: 0000000000000087 RBX: dffffc0000000000 RCX: 98444bb9450e1700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 00000000000006c0 R08: ffffc900001b6f87 R09: 1ffff92000036df0
R10: dffffc0000000000 R11: fffff52000036df1 R12: ffff88804ce8add0
R13: ffff888059bc7000 R14: ffff888059bc6fe8 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff88808d683000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555bb765c8 CR3: 000000001fd7c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 skb_under_panic net/core/skbuff.c:223 [inline]
 skb_push+0xc3/0xe0 net/core/skbuff.c:2641
 ip6gre_header+0xc8/0x790 net/ipv6/ip6_gre.c:1371
 dev_hard_header include/linux/netdevice.h:3436 [inline]
 neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
 neigh_output include/net/neighbour.h:556 [inline]
 ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136
 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
 ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
 mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
 mld_send_cr net/ipv6/mcast.c:2154 [inline]
 mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
Code: c7 e0 1a 6f 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 8e 94 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001b7280 EFLAGS: 00010282
RAX: 0000000000000087 RBX: dffffc0000000000 RCX: 98444bb9450e1700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 00000000000006c0 R08: ffffc900001b6f87 R09: 1ffff92000036df0
R10: dffffc0000000000 R11: fffff52000036df1 R12: ffff88804ce8add0
R13: ffff888059bc7000 R14: ffff888059bc6fe8 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff88808d683000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc5c02a230 CR3: 000000003b4e8000 CR4: 0000000000352ef0

Crashes (127):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 20:30 upstream 2061f18ad76e d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/28 04:21 upstream d26143bb38e2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ip6gre_header
2025/12/28 01:57 upstream c53f467229a7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root kernel BUG in ip6gre_header
2025/12/21 08:22 upstream d8ba32c5a460 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in ip6gre_header
2025/12/17 22:27 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in ip6gre_header
2025/12/17 12:01 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root kernel BUG in ip6gre_header
2025/12/15 14:08 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in ip6gre_header
2025/12/14 06:58 upstream 4a298a43f5e3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root kernel BUG in ip6gre_header
2025/12/14 06:20 upstream 4a298a43f5e3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root kernel BUG in ip6gre_header
2025/12/12 21:05 upstream 187d0801404f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in ip6gre_header
2025/12/12 19:40 upstream 187d0801404f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in ip6gre_header
2025/12/05 02:20 upstream 6dfafbd0299a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root kernel BUG in ip6gre_header
2025/12/28 19:03 upstream d26143bb38e2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/27 12:52 upstream c53f467229a7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/27 09:33 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/27 08:29 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/27 07:17 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/26 19:45 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/26 01:41 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/24 21:13 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/23 03:58 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/23 01:55 upstream 9448598b22c5 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/21 20:05 upstream 9094662f6707 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/20 20:11 upstream d8ba32c5a460 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/20 12:55 upstream dd9b004b7ff3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/20 02:37 upstream dd9b004b7ff3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/19 22:23 upstream dd9b004b7ff3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/17 16:43 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/17 02:00 upstream 40fbbd64bba6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/13 20:45 upstream 4a298a43f5e3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/12 23:25 upstream 187d0801404f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 kernel BUG in ip6gre_header
2025/12/29 04:04 upstream c875a6c32467 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/29 01:41 upstream c875a6c32467 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/28 06:20 upstream d26143bb38e2 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/26 15:28 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in ip6gre_header
2025/12/26 12:19 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/26 10:44 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/25 12:10 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/25 09:31 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/24 17:04 upstream b927546677c8 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/24 11:00 upstream b927546677c8 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/24 05:25 upstream b927546677c8 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/18 16:00 upstream ea1013c15392 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in ip6gre_header
2025/12/18 14:52 upstream ea1013c15392 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/18 12:34 upstream ea1013c15392 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/17 10:08 upstream ea1013c15392 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in ip6gre_header
2025/12/15 04:16 upstream 8f0b4cce4481 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ip6gre_header
2025/12/15 01:40 upstream 8f0b4cce4481 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in ip6gre_header
2025/12/14 21:27 upstream 8f0b4cce4481 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in ip6gre_header
2025/12/20 07:53 upstream dd9b004b7ff3 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/18 11:08 upstream ea1013c15392 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/18 07:29 upstream ea1013c15392 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/18 03:09 upstream ea1013c15392 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/16 17:36 upstream 40fbbd64bba6 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/16 07:40 upstream 8f0b4cce4481 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in ip6gre_header
2025/12/22 14:50 net-next 7b8e9264f55a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce kernel BUG in ip6gre_header
2025/12/06 09:23 linux-next 6987d58a9cbc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in ip6gre_header
* Struck through repros no longer work on HEAD.