syzbot


WARNING in qdisc_pkt_len_segs_init

Status: upstream: reported on 2026/06/24 07:20
Subsystems: net
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+d5d0d598a4cfdfafdc3b@syzkaller.appspotmail.com
First crash: 68d, last: 1d13h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
462fb050-1773-47ef-8a64-e6fd0f366877 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ✅ WARNING in qdisc_pkt_len_segs_init 2026/05/30 18:19 2026/05/30 18:19 2026/05/30 19:39 6b4a844333e83556da95d61d7f207e7ef5cd4bc6

			
		
7d36043f-5556-4821-bb45-5fd0c49d64d8 assessment-security 💥 WARNING in qdisc_pkt_len_segs_init 2026/05/14 11:21 2026/05/14 11:21 2026/05/14 11:22 6ccb967e465e832a7bfd7a116ad00d52a0923a5d
failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128
From /app/workdir/repo/linux
 * branch                HEAD       -> FETCH_HEAD
Updating files:  ...
truncated to first 200 bytes; open job for full error
Discussions (2)
Title Replies (including bot) Last reply
[PATCH net] net: clear transport header during tunnel decapsulation 3 (3) 2026/06/24 11:44
[syzbot] [net?] WARNING in qdisc_pkt_len_segs_init 0 (1) 2026/06/24 07:20

Sample crash report:
------------[ cut here ]------------
len > ((int)(~0U >> 1))
WARNING: ./include/linux/skbuff.h:2866 at pskb_may_pull_reason include/linux/skbuff.h:2866 [inline], CPU#0: syz.0.5520/24128
WARNING: ./include/linux/skbuff.h:2866 at pskb_may_pull include/linux/skbuff.h:2884 [inline], CPU#0: syz.0.5520/24128
WARNING: ./include/linux/skbuff.h:2866 at qdisc_pkt_len_segs_init+0x4b4/0xa30 net/core/dev.c:4138, CPU#0: syz.0.5520/24128
Modules linked in:
CPU: 0 UID: 0 PID: 24128 Comm: syz.0.5520 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pskb_may_pull_reason include/linux/skbuff.h:2866 [inline]
RIP: 0010:pskb_may_pull include/linux/skbuff.h:2884 [inline]
RIP: 0010:qdisc_pkt_len_segs_init+0x4b4/0xa30 net/core/dev.c:4138
Code: 00 00 02 00 31 ff e8 1b 3d 49 f8 81 e3 00 00 02 00 0f 85 fd 00 00 00 e8 ca 38 49 f8 45 89 e7 e9 2c ff ff ff e8 bd 38 49 f8 90 <0f> 0b 90 e9 ee fd ff ff 44 89 e7 89 de e8 6a 3a 49 f8 41 39 dc 0f
RSP: 0018:ffffc90000007660 EFLAGS: 00010246
RAX: ffffffff897ccc53 RBX: 0000000000000003 RCX: ffff8880761b8000
RDX: 0000000000000100 RSI: 00000000fffffffa RDI: 0000000000000000
RBP: ffff888034a70b40 R08: ffff88807bd48067 R09: 1ffff1100f7a900c
R10: dffffc0000000000 R11: ffffed100f7a900d R12: 00000000fffffffa
R13: dffffc0000000000 R14: 1ffff1100694e183 R15: ffff888068a29b98
FS:  00007f26d46806c0(0000) GS:ffff888125272000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 00000000894be000 CR4: 00000000003526f0
DR0: 0000000000000006 DR1: 0000000000000000 DR2: 000000007fffdff5
DR3: 0000800000000005 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 sch_handle_ingress net/core/dev.c:4479 [inline]
 __netif_receive_skb_core+0x13aa/0x30b0 net/core/dev.c:6057
 __netif_receive_skb_list_core+0x24d/0x830 net/core/dev.c:6281
 __netif_receive_skb_list net/core/dev.c:6348 [inline]
 netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6439
 gro_normal_list include/net/gro.h:523 [inline]
 gro_flush_normal include/net/gro.h:531 [inline]
 napi_complete_done+0x299/0x730 net/core/dev.c:6807
 gro_cell_poll+0x5ab/0x5d0 net/core/gro_cells.c:74
 __napi_poll+0xaa/0x330 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x61d/0xf50 net/core/dev.c:7949
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x616/0x790 drivers/net/tun.c:-1
 tun_get_user+0x2b04/0x4350 drivers/net/tun.c:1986
 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2032
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 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: 0033:0x7f26d379ce59
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:00007f26d4680028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f26d3a15fa0 RCX: 00007f26d379ce59
RDX: 000000000000fdef RSI: 00002000000002c0 RDI: 000000000000000a
RBP: 00007f26d3832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26d3a16038 R14: 00007f26d3a15fa0 R15: 00007f26d3b3fa48
 </TASK>

Crashes (22):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/17 19:17 upstream 9c87e61e3c57 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/15 07:08 upstream 66182ca873a4 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in qdisc_pkt_len_segs_init
2026/06/21 23:11 upstream 8cd8cf7a07e5 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in qdisc_pkt_len_segs_init
2026/06/20 09:15 upstream 1a3746ccbb0a 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in qdisc_pkt_len_segs_init
2026/05/31 18:55 upstream 174914ea5513 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in qdisc_pkt_len_segs_init
2026/06/06 15:45 upstream 8e65320d91cd cc095639 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in qdisc_pkt_len_segs_init
2026/05/30 09:10 upstream 9215e74f228f 6b4a8443 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in qdisc_pkt_len_segs_init
2026/05/19 16:32 upstream ab5fce87a778 2aa09d96 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in qdisc_pkt_len_segs_init
2026/06/05 23:25 upstream 06121e12c27a cc095639 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in qdisc_pkt_len_segs_init
2026/06/24 00:11 net e82d8cc4321c 042555ff .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/06/18 15:43 net 7d8297e26b4e a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/06/18 07:48 net b85966adbf5d b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/25 14:28 net 87a1e0fe7776 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/22 10:51 net 68993ced0f61 e16cf9f3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/06/22 10:46 net-next b85966adbf5d 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/25 21:56 net-next 0f700d144b5a c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/14 11:38 net-next 1f8fd0fe5641 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/06 22:12 net-next 2281958e6007 cbcd9ea0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/05/03 21:34 net-next 98878ed91b68 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/04/23 22:09 net-next 1f5ffc672165 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/04/17 22:31 net-next 1f5ffc672165 24ecfc1e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in qdisc_pkt_len_segs_init
2026/06/14 04:48 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 596d152bc5e3 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in qdisc_pkt_len_segs_init
* Struck through repros no longer work on HEAD.