WARNING in __skb_flow_dissect

Status: upstream: reported C repro on 2026/01/17 07:47
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+84112fa28f0a5cc0669f@syzkaller.appspotmail.com
First crash: 283d, last: 20h49m
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/09/25 linux-6.1.y (ToT) 1a8763b93150 C [report] WARNING in __skb_flow_dissect
2026/09/25 upstream (ToT) 165768bb7026 C Didn't crash
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __skb_flow_dissect (6) net -1 1 903d 903d 27/29 fixed on 2024/08/14 19:57
upstream WARNING in __skb_flow_dissect net -1 syz 3 2938d 2939d 11/29 fixed on 2018/10/11 18:37
upstream WARNING in __skb_flow_dissect (5) net -1 1 943d 943d 0/29 closed as invalid on 2024/04/26 11:59
upstream WARNING in __skb_flow_dissect (7) net -1 275 287d 279d 29/29 fixed on 2026/05/06 16:40
linux-6.6 WARNING in __skb_flow_dissect origin:lts-only -1 syz, C 88 6d03h 197d 0/2 upstream: reported C repro on 2026/04/13 06:50
upstream WARNING in __skb_flow_dissect (3) net -1 syz 224 2842d 2931d 11/29 fixed on 2019/03/06 07:43
upstream WARNING in __skb_flow_dissect (8) prio:low net -1 syz, C 5 30d 28d 26/29 upstream: reported C repro on 2026/09/28 19:41
upstream WARNING in __skb_flow_dissect (4) net -1 syz, C error 6 1451d 1461d 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 (207):
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
2026/10/26 16:10 linux-6.1.y 79807e970724 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/23 21:55 linux-6.1.y 79807e970724 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/23 11:13 linux-6.1.y 79807e970724 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/23 09:27 linux-6.1.y 79807e970724 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/23 09:18 linux-6.1.y 79807e970724 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/22 14:59 linux-6.1.y 79807e970724 b55fad29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/21 09:18 linux-6.1.y 79807e970724 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/19 19:07 linux-6.1.y 79807e970724 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/18 13:45 linux-6.1.y 79807e970724 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/15 04:14 linux-6.1.y a500ba24937a 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/14 01:57 linux-6.1.y a500ba24937a 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/13 10:42 linux-6.1.y a500ba24937a 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/09 03:58 linux-6.1.y a500ba24937a b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/08 20:39 linux-6.1.y a500ba24937a b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/08 08:05 linux-6.1.y a500ba24937a 4f6a9fcf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/06 02:49 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/03 14:35 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/02 20:18 linux-6.1.y 1a8763b93150 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/02 04:02 linux-6.1.y 1a8763b93150 6d32eb1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/01 15:15 linux-6.1.y 1a8763b93150 f5cdae2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/30 21:23 linux-6.1.y 1a8763b93150 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/30 08:40 linux-6.1.y 1a8763b93150 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/29 20:11 linux-6.1.y 1a8763b93150 328436b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/29 08:11 linux-6.1.y 1a8763b93150 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/26 06:30 linux-6.1.y 1a8763b93150 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/26 01:11 linux-6.1.y 1a8763b93150 f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/09/24 07:15 linux-6.1.y 1a8763b93150 0281b448 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __skb_flow_dissect
2026/10/20 17:45 linux-6.1.y 79807e970724 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/19 02:27 linux-6.1.y 79807e970724 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/18 11:05 linux-6.1.y 79807e970724 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/16 09:08 linux-6.1.y 79807e970724 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/16 00:29 linux-6.1.y 79807e970724 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/15 09:46 linux-6.1.y a500ba24937a 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/12 18:19 linux-6.1.y a500ba24937a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/11 21:12 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/11 03:40 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/09 21:45 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/08 13:35 linux-6.1.y a500ba24937a 4f6a9fcf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/06 06:19 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/03 22:12 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/03 15:48 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/10/03 13:01 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/23 21:08 linux-6.1.y 1a8763b93150 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/23 15:49 linux-6.1.y 1a8763b93150 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/23 01:20 linux-6.1.y 1a8763b93150 5207b90e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __skb_flow_dissect
2026/09/22 10:17 linux-6.1.y 1a8763b93150 e12281bd .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.