WARNING in skb_checksum_help

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f2ecb86 Linux 4.14.212
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17f30e93500000
kernel config: https://syzkaller.appspot.com/x/.config?x=80549830ca6ffbb2
dashboard link: https://syzkaller.appspot.com/bug?extid=05580173379ccad5376e
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+055801...@syzkaller.appspotmail.com

netlink_ack+0x514/0x9a0 net/netlink/af_netlink.c:2403
nfnl_err_deliver net/netfilter/nfnetlink.c:270 [inline]
nfnetlink_rcv_batch net/netfilter/nfnetlink.c:451 [inline]
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:495 [inline]
nfnetlink_rcv+0x147b/0x1da0 net/netfilter/nfnetlink.c:513
: caps=(0x0000000000000000, 0x00000144401d7c69) len=284 data_len=0 gso_size=116 gso_type=1 ip_summed=3
netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7 at net/core/dev.c:2609 skb_warn_bad_offload.cold+0x1d1/0x44d net/core/dev.c:2609
Kernel panic - not syncing: panic_on_warn set ...

netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45e149
RSP: 002b:00007fb601695c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 000000000045e149
RDX: 0000000000000000 RSI: 000000002000c2c0 RDI: 0000000000000003
RBP: 00007fb601695ca0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
R13: 00007ffda1bfec5f R14: 00007fb6016969c0 R15: 000000000119bf8c
CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted 4.14.212-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
panic+0x1f9/0x42d kernel/panic.c:183
__warn.cold+0x20/0x4b kernel/panic.c:547
report_bug+0x208/0x249 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:skb_warn_bad_offload.cold+0x1d1/0x44d net/core/dev.c:2609
RSP: 0018:ffff8880b540efb0 EFLAGS: 00010286
RAX: 0000000000000066 RBX: ffff888099abb828 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff878bbac0 RDI: ffffed1016a81dec
RBP: ffffffff88559320 R08: 0000000000000066 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff88557080
R13: 0000000000000074 R14: 0000000000000000 R15: 000000000000011c
skb_checksum_help+0x627/0x7d0 net/core/dev.c:2630
checksum_tg+0x52/0x65 net/netfilter/xt_CHECKSUM.c:29
ipt_do_table+0xa9a/0x16f0 net/ipv4/netfilter/ip_tables.c:353
ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:64 [inline]
iptable_mangle_hook+0x2d5/0x560 net/ipv4/netfilter/iptable_mangle.c:89
nf_hook_entry_hookfn include/linux/netfilter.h:108 [inline]
nf_hook_slow+0xb0/0x1a0 net/netfilter/core.c:467
nf_hook include/linux/netfilter.h:205 [inline]
__ip_local_out+0x398/0x730 net/ipv4/ip_output.c:114
ip_local_out+0x25/0x170 net/ipv4/ip_output.c:123
ip_queue_xmit+0x7d3/0x1a80 net/ipv4/ip_output.c:505
__tcp_transmit_skb+0x17e2/0x2cb0 net/ipv4/tcp_output.c:1133
tcp_transmit_skb net/ipv4/tcp_output.c:1149 [inline]
tcp_write_xmit+0x69d/0x4e10 net/ipv4/tcp_output.c:2393
__tcp_push_pending_frames+0xa0/0x2d0 net/ipv4/tcp_output.c:2577
tcp_push_pending_frames include/net/tcp.h:1778 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5132 [inline]
tcp_rcv_state_process+0xca9/0x494e net/ipv4/tcp_input.c:6175
tcp_v4_do_rcv+0x2c4/0x7d0 net/ipv4/tcp_ipv4.c:1498
tcp_v4_rcv+0x275c/0x3560 net/ipv4/tcp_ipv4.c:1750
ip_local_deliver_finish+0x3f2/0xab0 net/ipv4/ip_input.c:216
NF_HOOK include/linux/netfilter.h:250 [inline]
ip_local_deliver+0x167/0x460 net/ipv4/ip_input.c:257
dst_input include/net/dst.h:476 [inline]
ip_rcv_finish+0x6e3/0x19f0 net/ipv4/ip_input.c:396
NF_HOOK include/linux/netfilter.h:250 [inline]
ip_rcv+0x8a7/0xf01 net/ipv4/ip_input.c:493
__netif_receive_skb_core+0x15ee/0x2a30 net/core/dev.c:4474
__netif_receive_skb+0x27/0x1a0 net/core/dev.c:4512
process_backlog+0x218/0x6f0 net/core/dev.c:5194
napi_poll net/core/dev.c:5596 [inline]
net_rx_action+0x466/0xfd0 net/core/dev.c:5662
__do_softirq+0x254/0xa1d kernel/softirq.c:288
run_ksoftirqd+0x50/0x1a0 kernel/softirq.c:670
smpboot_thread_fn+0x5c1/0x920 kernel/smpboot.c:164
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.