WARNING in xfrm_policy_inexact_list_reinsert

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    4010b622 Merge branch 'dax-fix-5.3-rc3' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13e2829fa00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e397351d2615e10
dashboard link: https://syzkaller.appspot.com/bug?extid=8cc27ace5f6972910b31
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)

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+8cc27ace5f6972910b31@xxxxxxxxxxxxxxxxxxxxxxxxx

WARNING: CPU: 1 PID: 6756 at net/xfrm/xfrm_policy.c:877  
xfrm_policy_inexact_list_reinsert+0x625/0x6e0 net/xfrm/xfrm_policy.c:877
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 6756 Comm: syz-executor.1 Not tainted 5.3.0-rc2+ #57
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x2f8 lib/dump_stack.c:113
 panic+0x29b/0x7d9 kernel/panic.c:219
 __warn+0x22f/0x230 kernel/panic.c:576
 report_bug+0x190/0x290 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0xd7/0x440 arch/x86/kernel/traps.c:272
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:291
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:xfrm_policy_inexact_list_reinsert+0x625/0x6e0  
net/xfrm/xfrm_policy.c:877
Code: ef e8 6f 32 0f fb 4d 8b 6d 00 4c 39 6d 90 0f 85 81 fa ff ff e9 b0 00  
00 00 e8 c7 87 d4 fa 0f 0b e9 fa fa ff ff e8 bb 87 d4 fa <0f> 0b e9 75 ff  
ff ff e8 af 87 d4 fa 0f 0b eb a9 44 89 f1 80 e1 07
RSP: 0018:ffff888052caf080 EFLAGS: 00010283
RAX: ffffffff86a35975 RBX: 00000000ffffff20 RCX: 0000000000040000
RDX: ffffc9000816a000 RSI: 00000000000005cd RDI: 00000000000005ce
RBP: ffff888052caf110 R08: ffffffff86a358ac R09: ffffffff86a3514c
R10: ffff88805914c380 R11: 0000000000000002 R12: 0000000000000000
R13: ffff888092fa6aa0 R14: 000000000000007e R15: 000000000000000a
 xfrm_policy_inexact_node_reinsert net/xfrm/xfrm_policy.c:922 [inline]
 xfrm_policy_inexact_node_merge net/xfrm/xfrm_policy.c:958 [inline]
 xfrm_policy_inexact_insert_node+0x537/0xb50 net/xfrm/xfrm_policy.c:1023
 xfrm_policy_inexact_alloc_chain+0x62b/0xbd0 net/xfrm/xfrm_policy.c:1139
 xfrm_policy_inexact_insert+0xe8/0x1540 net/xfrm/xfrm_policy.c:1182
 xfrm_policy_insert+0xdf/0xce0 net/xfrm/xfrm_policy.c:1574
 xfrm_add_policy+0x4cf/0x9b0 net/xfrm/xfrm_user.c:1670
 xfrm_user_rcv_msg+0x46b/0x720 net/xfrm/xfrm_user.c:2676
 netlink_rcv_skb+0x1f0/0x460 net/netlink/af_netlink.c:2477
 xfrm_netlink_rcv+0x74/0x90 net/xfrm/xfrm_user.c:2684
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x809/0x9a0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0xa70/0xd30 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg net/socket.c:657 [inline]
 ___sys_sendmsg+0x66b/0x9a0 net/socket.c:2311
 __sys_sendmsg net/socket.c:2356 [inline]
 __do_sys_sendmsg net/socket.c:2365 [inline]
 __se_sys_sendmsg net/socket.c:2363 [inline]
 __x64_sys_sendmsg+0x1cf/0x290 net/socket.c:2363
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f16cc51ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f16cc51f6d4
R13: 00000000004c776b R14: 00000000004dceb8 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..


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