bisecting fixing commit since 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796
building syzkaller on 5d7b90f1af2e3bf33992b75e7fcf0bab6bf49bd6
testing commit 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796 with gcc (GCC) 8.1.0
kernel signature: 111a9b9358d5591692192c7ef3c9918a4a1fb8152b589b9b0d731a1a77c41352
run #0: crashed: WARNING in xfrm_policy_insert
run #1: crashed: WARNING in xfrm_policy_insert
run #2: crashed: WARNING in xfrm_policy_insert
run #3: crashed: WARNING in xfrm_policy_insert
run #4: crashed: WARNING in xfrm_policy_insert
run #5: crashed: WARNING in xfrm_policy_insert
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing current HEAD ab9dfda232481dcfaf549ce774004d116fc80c13
testing commit ab9dfda232481dcfaf549ce774004d116fc80c13 with gcc (GCC) 8.1.0
kernel signature: df7e23fa4845ea569fd43018771735f119727f51586c6f0ba18e3de3a4205d59
run #0: crashed: WARNING in xfrm_policy_insert
run #1: crashed: WARNING in xfrm_policy_insert
run #2: crashed: WARNING in xfrm_policy_insert
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
revisions tested: 2, total time: 39m55.371851253s (build: 19m0.549633094s, test: 19m33.137378886s)
the crash still happens on HEAD
commit msg: Linux 4.14.180
crash: WARNING in xfrm_policy_insert
netlink: 40803 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 40803 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 40803 bytes leftover after parsing attributes in process `syz-executor.4'.
netlink: 11579 bytes leftover after parsing attributes in process `syz-executor.5'.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 32526 at net/xfrm/xfrm_policy.c:754 xfrm_policy_insert+0x58f/0x14d0 net/xfrm/xfrm_policy.c:799
netlink: 11579 bytes leftover after parsing attributes in process `syz-executor.2'.
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 32526 Comm: syz-executor.5 Not tainted 4.14.180-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+0xf7/0x13b lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
netlink: 40803 bytes leftover after parsing attributes in process `syz-executor.0'.
 __warn.cold.8+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
netlink: 11579 bytes leftover after parsing attributes in process `syz-executor.3'.
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:xfrm_policy_insert+0x58f/0x14d0 net/xfrm/xfrm_policy.c:754
RSP: 0018:ffff8880a97af628 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88809f4c9680 RCX: 0000000000000000
RDX: 000000000088fe10 RSI: ffffed1013e184af RDI: ffff88809f4c98b0
RBP: ffff8880a97af6c0 R08: ffff8880a0b64dc8 R09: ffff88809f0c257c
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88809f0c24c0
 xfrm_add_policy+0x264/0x590 net/xfrm/xfrm_user.c:1624
 xfrm_user_rcv_msg+0x344/0x6f0 net/xfrm/xfrm_user.c:2617
 netlink_rcv_skb+0x133/0x370 net/netlink/af_netlink.c:2433
 xfrm_netlink_rcv+0x69/0x90 net/xfrm/xfrm_user.c:2625
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x40b/0x600 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x730/0xbd0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:656
 SYSC_sendto+0x1e3/0x2c0 net/socket.c:1763
 SyS_sendto+0x9/0x10 net/socket.c:1731
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c6c9
RSP: 002b:00007ff170c3ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ff170c3f6d4 RCX: 000000000045c6c9
RDX: 000000000000ff3b RSI: 0000000020000000 RDI: 0000000000000005
RBP: 000000000076bf20 R08: 0000000000000000 R09: fffffffffffffd62
R10: 0f00000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009d6 R14: 00000000004cc793 R15: 000000000076bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..