------------[ cut here ]------------
WARNING: ./include/linux/skbuff.h:3243 at skb_network_header_len include/linux/skbuff.h:3243 [inline], CPU#0: syz.0.10259/10402
WARNING: ./include/linux/skbuff.h:3243 at tcf_skbmod_act+0x5e0/0x69c net/sched/act_skbmod.c:55, CPU#0: syz.0.10259/10402
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 0 UID: 0 PID: 10402 Comm: syz.0.10259 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: ARM-Versatile Express
Call trace: 
[<80201998>] (dump_backtrace) from [<80201a8c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:82a20f78 r6:00000000 r5:82336570 r4:00000001
[<80201a74>] (show_stack) from [<8021ec68>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201a74>] (show_stack) from [<8021ec68>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021ec0c>] (dump_stack_lvl) from [<8021ec94>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r7:82a20f78 r6:00000000 r5:840e6200 r4:82c85d40
[<8021ec7c>] (dump_stack) from [<80202590>] (vpanic+0x114/0x320 kernel/panic.c:651)
[<8020247c>] (vpanic) from [<802027d0>] (trace_suspend_resume+0x0/0x100 kernel/panic.c:788)
 r7:8170f304
[<8020279c>] (panic) from [<80251b50>] (check_panic_on_warn kernel/panic.c:525 [inline])
[<8020279c>] (panic) from [<80251b50>] (get_taint+0x0/0x1c kernel/panic.c:520)
 r3:82a0b144 r2:00000001 r1:8231c298 r0:82323c10
[<80251ad8>] (check_panic_on_warn) from [<80251ccc>] (__warn+0x98/0x1a4 kernel/panic.c:1104)
[<80251c34>] (__warn) from [<80251f50>] (warn_slowpath_fmt+0x178/0x1f4 kernel/panic.c:1136)
 r8:00000009 r7:82335d94 r6:dfa5db34 r5:840e6200 r4:00000000
[<80251ddc>] (warn_slowpath_fmt) from [<8170f304>] (skb_network_header_len include/linux/skbuff.h:3243 [inline])
[<80251ddc>] (warn_slowpath_fmt) from [<8170f304>] (tcf_skbmod_act+0x5e0/0x69c net/sched/act_skbmod.c:55)
 r10:00000018 r9:5b4fd000 r8:00000000 r7:847fe000 r6:00000010 r5:85d21840
 r4:86743240
[<8170ed24>] (tcf_skbmod_act) from [<816fdedc>] (tc_act include/net/tc_wrapper.h:254 [inline])
[<8170ed24>] (tcf_skbmod_act) from [<816fdedc>] (tcf_action_exec+0xac/0x154 net/sched/act_api.c:1150)
 r10:86743240 r9:00000020 r8:93a41c00 r7:dfa5dc64 r6:00000001 r5:847fe000
 r4:00000000
[<816fde30>] (tcf_action_exec) from [<81754a34>] (tcf_exts_exec include/net/pkt_cls.h:361 [inline])
[<816fde30>] (tcf_action_exec) from [<81754a34>] (basic_classify+0xbc/0xf8 net/sched/cls_basic.c:54)
 r10:00000000 r9:85d01f00 r8:dfa5dbe8 r7:86743240 r6:82516e2c r5:dfa5dc64
 r4:93a41c80
[<81754978>] (basic_classify) from [<816f7540>] (tc_classify include/net/tc_wrapper.h:260 [inline])
[<81754978>] (basic_classify) from [<816f7540>] (__tcf_classify net/sched/cls_api.c:1779 [inline])
[<81754978>] (basic_classify) from [<816f7540>] (tcf_classify+0x194/0x418 net/sched/cls_api.c:1875)
 r10:00000000 r9:00000000 r8:dfa5dc64 r7:85cb1d80 r6:86743240 r5:00000000
 r4:85cb1d80 r3:81754978
[<816f73ac>] (tcf_classify) from [<8165c8b8>] (tc_run+0x14c/0x1d4 net/core/dev.c:4415)
 r10:5b4fd000 r9:00000001 r8:a42be4b0 r7:dfa5dcd0 r6:ff7bb4b0 r5:85df7394
 r4:86743240
[<8165c76c>] (tc_run) from [<8166a0d8>] (sch_handle_ingress net/core/dev.c:4490 [inline])
[<8165c76c>] (tc_run) from [<8166a0d8>] (__netif_receive_skb_core.constprop.0+0x3cc/0xf64 net/core/dev.c:6067)
 r10:00000000 r9:85f70000 r8:dfa5dd74 r7:828d5598 r6:82516e2c r5:85252408
 r4:86743240
[<81669d0c>] (__netif_receive_skb_core.constprop.0) from [<8166af28>] (__netif_receive_skb_one_core+0x40/0x84 net/core/dev.c:6214)
 r10:8f5fa12c r9:dfa5de40 r8:85f71700 r7:8f5fa30c r6:00000000 r5:840e6200
 r4:85f70000
[<8166aee8>] (__netif_receive_skb_one_core) from [<8166afb4>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:6329)
 r5:840e6200 r4:86743240
[<8166af9c>] (__netif_receive_skb) from [<8166b034>] (netif_receive_skb_internal net/core/dev.c:6415 [inline])
[<8166af9c>] (__netif_receive_skb) from [<8166b034>] (netif_receive_skb+0x3c/0x268 net/core/dev.c:6474)
 r5:840e6200 r4:86743240
[<8166aff8>] (netif_receive_skb) from [<80de5db0>] (tun_rx_batched drivers/net/tun.c:1487 [inline])
[<8166aff8>] (netif_receive_skb) from [<80de5db0>] (tun_get_user+0xe9c/0x1190 drivers/net/tun.c:1955)
 r7:8f5fa30c r6:00000000 r5:86743240 r4:85f70700
[<80de4f14>] (tun_get_user) from [<80de69fc>] (tun_chr_write_iter+0x60/0xc8 drivers/net/tun.c:2001)
 r10:81d879ec r9:840e6200 r8:8f5fa000 r7:85f70700 r6:00000000 r5:dfa5def0
 r4:dfa5df08
[<80de699c>] (tun_chr_write_iter) from [<805a1390>] (new_sync_write fs/read_write.c:595 [inline])
[<80de699c>] (tun_chr_write_iter) from [<805a1390>] (vfs_write fs/read_write.c:687 [inline])
[<80de699c>] (tun_chr_write_iter) from [<805a1390>] (vfs_write+0x27c/0x42c fs/read_write.c:667)
 r8:80de699c r7:dfa5df68 r6:20000300 r5:8620c800 r4:0000001c
[<805a1114>] (vfs_write) from [<805a16b4>] (ksys_write+0x74/0xec fs/read_write.c:739)
 r10:00000004 r9:840e6200 r8:8020029c r7:00000000 r6:00000000 r5:8620c800
 r4:8620c801
[<805a1640>] (ksys_write) from [<805a173c>] (__do_sys_write fs/read_write.c:750 [inline])
[<805a1640>] (ksys_write) from [<805a173c>] (sys_write+0x10/0x14 fs/read_write.c:747)
 r7:00000004 r6:00356310 r5:00000000 r4:00000000
[<805a172c>] (sys_write) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdfa5dfa8 to 0xdfa5dff0)
dfa0:                   00000000 00000000 00000004 20000300 0000001c 00000000
dfc0: 00000000 00000000 00356310 00000004 003562d8 00000000 00000001 76f420dc
dfe0: 76f41e88 76f41e78 00018fa0 00130a50
Rebooting in 86400 seconds..