BUG: unable to handle kernel paging request in xfrmi_decode_session (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 106fa147 Linux 4.19.127
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=118123ca100000
kernel config: https://syzkaller.appspot.com/x/.config?x=b4a714eef836e3f3
dashboard link: https://syzkaller.appspot.com/bug?extid=4dbbeab3c727f6a215e1
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4dbbea...@syzkaller.appspotmail.com

IPVS: ftp: loaded support on port[0] = 21
BUG: unable to handle kernel paging request at ffffffff00000000
PGD 8a70067 P4D 8a70067 PUD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 15034 Comm: syz-executor.0 Not tainted 4.19.127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:read_pnet include/net/net_namespace.h:300 [inline]
RIP: 0010:xs_net include/net/xfrm.h:253 [inline]
RIP: 0010:xfrmi_decode_session+0x154/0x780 net/xfrm/xfrm_interface.c:94
Code: 80 3c 02 00 0f 85 f4 05 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5c dc 10 48 89 da 48 c1 ea 03 80 3c 02 00 0f 85 c7 05 00 00 <4c> 8b 23 e8 44 58 31 fb e8 cf a8 42 fb 45 31 c9 45 31 c0 31 d2 31
RSP: 0018:ffff8881c2346ff8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffff00000000 RCX: ffffc90005ca5000
RDX: 1fffffffe0000000 RSI: ffffffff8624e164 RDI: ffff888092539788
RBP: 0000000000000039 R08: ffff8881c2746540 R09: ffffed1015ce473b
R10: ffffed1015ce473a R11: ffff8880ae7239d3 R12: ffff888092539780
R13: 00000000000007ff R14: ffff8881ba8cb700 R15: 0000000000000000
FS: 00007fa902c61700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff00000000 CR3: 00000001cd2d4000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__xfrm_policy_check+0x1eb/0x2310 net/xfrm/xfrm_policy.c:2339
__xfrm_policy_check2 include/net/xfrm.h:1201 [inline]
xfrm_policy_check include/net/xfrm.h:1206 [inline]
xfrm6_policy_check include/net/xfrm.h:1216 [inline]
vti6_rcv+0x4f3/0x900 net/ipv6/ip6_vti.c:316
xfrm6_esp_rcv+0xc8/0x220 net/ipv6/xfrm6_protocol.c:74
ip6_input_finish+0x46f/0x1790 net/ipv6/ip6_input.c:395
NF_HOOK include/linux/netfilter.h:289 [inline]
ip6_input+0xcf/0x3c0 net/ipv6/ip6_input.c:438
ip6_mc_input+0x403/0xa88 net/ipv6/ip6_input.c:515
dst_input include/net/dst.h:453 [inline]
ip6_rcv_finish+0x1d9/0x2f0 net/ipv6/ip6_input.c:76
NF_HOOK include/linux/netfilter.h:289 [inline]
ipv6_rcv+0x101/0x400 net/ipv6/ip6_input.c:283
__netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:4960
__netif_receive_skb+0x27/0x1c0 net/core/dev.c:5072
netif_receive_skb_internal+0xf9/0x400 net/core/dev.c:5162
napi_frags_finish net/core/dev.c:5689 [inline]
napi_gro_frags+0x6cc/0xa00 net/core/dev.c:5762
tun_get_user+0x2b1e/0x4a30 drivers/net/tun.c:1943
tun_chr_write_iter+0xb0/0x150 drivers/net/tun.c:1989
call_write_iter include/linux/fs.h:1821 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x512/0x760 fs/read_write.c:487
__kernel_write+0x109/0x370 fs/read_write.c:506
write_pipe_buf+0x153/0x1e0 fs/splice.c:798
splice_from_pipe_feed fs/splice.c:503 [inline]
__splice_from_pipe+0x38f/0x7a0 fs/splice.c:627
splice_from_pipe+0xd9/0x140 fs/splice.c:662
default_file_splice_write+0x37/0x90 fs/splice.c:810
do_splice_from fs/splice.c:852 [inline]
do_splice fs/splice.c:1154 [inline]
__do_sys_splice fs/splice.c:1428 [inline]
__se_sys_splice+0xf18/0x1560 fs/splice.c:1408
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa902c60c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000507a00 RCX: 000000000045ca69
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000078bfa0 R08: 0000000000018100 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000bae R14: 00000000004cea37 R15: 00007fa902c616d4
Modules linked in:
CR2: ffffffff00000000
---[ end trace 7e2ef9a490a6af93 ]---
RIP: 0010:read_pnet include/net/net_namespace.h:300 [inline]
RIP: 0010:xs_net include/net/xfrm.h:253 [inline]
RIP: 0010:xfrmi_decode_session+0x154/0x780 net/xfrm/xfrm_interface.c:94
Code: 80 3c 02 00 0f 85 f4 05 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5c dc 10 48 89 da 48 c1 ea 03 80 3c 02 00 0f 85 c7 05 00 00 <4c> 8b 23 e8 44 58 31 fb e8 cf a8 42 fb 45 31 c9 45 31 c0 31 d2 31
RSP: 0018:ffff8881c2346ff8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffff00000000 RCX: ffffc90005ca5000
RDX: 1fffffffe0000000 RSI: ffffffff8624e164 RDI: ffff888092539788
RBP: 0000000000000039 R08: ffff8881c2746540 R09: ffffed1015ce473b
R10: ffffed1015ce473a R11: ffff8880ae7239d3 R12: ffff888092539780
R13: 00000000000007ff R14: ffff8881ba8cb700 R15: 0000000000000000
FS: 00007fa902c61700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff00000000 CR3: 00000001cd2d4000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

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