WARNING in __skb_flow_dissect

Status: upstream: reported C repro on 2026/01/17 07:47
Reported-by: syzbot+84112fa28f0a5cc0669f@syzkaller.appspotmail.com
First crash: 235d, last: 9h18m
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/06/26 upstream (ToT) 4edcdefd4083 C Failed due to an error; will retry later
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __skb_flow_dissect (6) net -1 1 855d 855d 27/29 fixed on 2024/08/14 19:57
upstream WARNING in __skb_flow_dissect net -1 syz 3 2890d 2891d 11/29 fixed on 2018/10/11 18:37
upstream WARNING in __skb_flow_dissect (5) net -1 1 895d 895d 0/29 closed as invalid on 2024/04/26 11:59
upstream WARNING in __skb_flow_dissect (7) net -1 275 239d 232d 29/29 fixed on 2026/05/06 16:40
linux-6.6 WARNING in __skb_flow_dissect origin:lts-only -1 syz, C 48 2d02h 149d 0/2 upstream: reported C repro on 2026/04/13 06:50
upstream WARNING in __skb_flow_dissect (3) net -1 syz 224 2794d 2883d 11/29 fixed on 2019/03/06 07:43
upstream WARNING in __skb_flow_dissect (4) net -1 syz, C error 6 1404d 1413d 22/29 fixed on 2023/02/24 13:50

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4513 at net/core/flow_dissector.c:1027 __skb_flow_dissect+0x95c/0x5988 net/core/flow_dissector.c:1022
Modules linked in:
CPU: 0 PID: 4513 Comm: kworker/0:12 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: rcu_gp process_srcu
pstate: 42400005 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __skb_flow_dissect+0x95c/0x5988 net/core/flow_dissector.c:1022
lr : __skb_flow_dissect+0x95c/0x5988 net/core/flow_dissector.c:1022
sp : ffff800008006740
x29: ffff800008006d90 x28: ffff800008006ea0 x27: 0000000000000002
x26: ffff0000c3f29270 x25: ffff8000152251dc x24: dfff800000000000
x23: 0000000000000000 x22: 1ffff00002a44a3c x21: 1ffff00002a44a3c
x20: ffff8000152251e2 x19: ffff700001000d2c x18: ffff800011b9bf60
x17: 00000000ffff0000 x16: ffff8000082d92bc x15: 0000000000000000
x14: 000000000000000a x13: 1ffff00002a44071 x12: 0000000000ff0100
x11: ff0080000fdb0e48 x10: 0000000000000000 x9 : ffff80000fdb0e48
x8 : ffff0000d6e7d340 x7 : ffff80000fdb7d28 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000002
x2 : 0000000000000008 x1 : ffff80001208bc80 x0 : 0000000000000001
Call trace:
 __skb_flow_dissect+0x95c/0x5988 net/core/flow_dissector.c:1022
 skb_flow_dissect_flow_keys include/linux/skbuff.h:1531 [inline]
 ___skb_get_hash+0x7c/0x5b8 net/core/flow_dissector.c:1708
 __skb_get_hash+0xb8/0x228 net/core/flow_dissector.c:1773
 skb_get_hash include/linux/skbuff.h:1573 [inline]
 nft_trace_init+0x188/0x358 net/netfilter/nf_tables_trace.c:292
 nft_do_chain+0x1260/0x12e8 net/netfilter/nf_tables_core.c:243
 nf_route_table_hook6+0x218/0x5ec net/netfilter/nft_chain_route.c:88
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb4/0x1f4 net/netfilter/core.c:614
 nf_hook include/linux/netfilter.h:257 [inline]
 __ip6_local_out+0x6b0/0x7cc net/ipv6/output_core.c:149
 ip6_local_out+0x3c/0x15c net/ipv6/output_core.c:159
 ip6tunnel_xmit include/net/ip6_tunnel.h:161 [inline]
 udp_tunnel6_xmit_skb+0x434/0x8f0 net/ipv6/ip6_udp_tunnel.c:109
 tipc_udp_xmit+0x484/0x9b8 net/tipc/udp_media.c:220
 tipc_udp_send_msg+0x254/0x380 net/tipc/udp_media.c:258
 tipc_bearer_xmit_skb+0x240/0x380 net/tipc/bearer.c:577
 tipc_disc_timeout+0x4d8/0x628 net/tipc/discover.c:338
 call_timer_fn+0x1b8/0x95c kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x478/0x6f0 kernel/time/timer.c:2023
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:2036
 handle_softirqs+0x318/0xc60 kernel/softirq.c:596
 __do_softirq+0x14/0x20 kernel/softirq.c:630
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:897
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:477 [inline]
 __irq_exit_rcu+0x23c/0x438 kernel/softirq.c:679
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691
 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
 el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 __arch_counter_get_cntvct_stable arch/arm64/include/asm/arch_timer.h:202 [inline]
 __delay_cycles+0x15c/0x21c arch/arm64/lib/delay.c:38
 __delay+0x144/0x1c4 arch/arm64/lib/delay.c:63
 __const_udelay arch/arm64/lib/delay.c:70 [inline]
 __udelay+0x60/0x70 arch/arm64/lib/delay.c:76
 try_check_zero+0x388/0x3b8 kernel/rcu/srcutree.c:975
 srcu_advance_state kernel/rcu/srcutree.c:1549 [inline]
 process_srcu+0x16c/0xffc kernel/rcu/srcutree.c:1651
 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292
 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
irq event stamp: 10229
hardirqs last  enabled at (10228): [<ffff8000081ab57c>] __local_bh_enable_ip+0x1f8/0x37c kernel/softirq.c:426
hardirqs last disabled at (10229): [<ffff800011a389f4>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (9714): [<ffff80000fdd2608>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (10207): [<ffff800008020164>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---

Crashes (110):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/10 17:55 linux-6.1.y 128a674368bf 29233ece .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/01/24 09:03 linux-6.1.y cd9b81672742 4f25b9b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/04 05:00 linux-6.1.y cf82dcca9634 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/04 00:53 linux-6.1.y cf82dcca9634 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/03 07:43 linux-6.1.y cf82dcca9634 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/02 18:12 linux-6.1.y cf82dcca9634 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/01 14:37 linux-6.1.y d64a499eea6b 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/31 20:26 linux-6.1.y d64a499eea6b 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/29 01:03 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/28 12:04 linux-6.1.y d64a499eea6b e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/27 18:21 linux-6.1.y 79a9660d699e 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/26 17:09 linux-6.1.y 05208478041c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/25 15:54 linux-6.1.y 05208478041c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/25 03:10 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/24 15:17 linux-6.1.y 05208478041c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/23 18:15 linux-6.1.y 05208478041c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/21 03:54 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/19 20:51 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/17 14:45 linux-6.1.y e4f7d8be268e 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/13 21:21 linux-6.1.y e4f7d8be268e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/12 21:42 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/12 21:35 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/10 22:35 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/08 07:53 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/07 14:02 linux-6.1.y e4f7d8be268e e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/06 22:52 linux-6.1.y 03f3a99e8e93 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/06 18:14 linux-6.1.y fb28aa725e05 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/05 06:47 linux-6.1.y fb28aa725e05 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/04 03:04 linux-6.1.y fb28aa725e05 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/08/03 14:36 linux-6.1.y fb28aa725e05 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/07/29 05:49 linux-6.1.y dc5c83b7f5f8 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/07/27 19:44 linux-6.1.y dc5c83b7f5f8 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/07/27 15:30 linux-6.1.y dc5c83b7f5f8 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/09 08:43 linux-6.1.y cf82dcca9634 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/08 01:39 linux-6.1.y cf82dcca9634 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/06 19:46 linux-6.1.y cf82dcca9634 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/04 14:03 linux-6.1.y cf82dcca9634 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/03 09:28 linux-6.1.y cf82dcca9634 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/02 20:24 linux-6.1.y cf82dcca9634 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/30 05:50 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/29 14:16 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/29 04:23 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/26 19:12 linux-6.1.y 05208478041c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/26 06:51 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/23 10:53 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/22 19:55 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/20 22:27 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/19 07:15 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/14 19:28 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/14 12:57 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/08/06 08:09 linux-6.1.y fb28aa725e05 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/07/30 10:56 linux-6.1.y 1016ca6176ee 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/01/17 07:47 linux-6.1.y bec0e10ee67e 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
* Struck through repros no longer work on HEAD.