bisecting fixing commit since 14b58326976de6ef3998eefec1dd7f8b38b97a75
building syzkaller on 5ce135324a84d6de67c913f1b725e3fc5ec39535
testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.1.0
kernel signature: 10840c9686d6d6e53496415371fbb9e4068eb2e0f7f21abf42dee7da1fda17c7
all runs: crashed: WARNING in rtnl_delete_link
testing current HEAD cbfa1702aaf69b2311ea1b35e04f113c48368c67
testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.1.0
kernel signature: 0477ebe2d3324ed550ff5fb0d31d242e28ab5ec665afb643aef13a37bc707f42
all runs: crashed: WARNING in rtnl_delete_link
revisions tested: 2, total time: 22m0.751402399s (build: 15m41.951369107s, test: 5m54.284429587s)
the crash still happens on HEAD
commit msg: Linux 4.14.198
crash: WARNING in rtnl_delete_link
bond0: vcan2 ether type (280) is different from other slaves (1), can not enslave it
bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Releasing backup interface bond_slave_1
bond0 (unregistering): Released all slaves
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8794 at net/core/dev.c:7224 rollback_registered_many+0x80c/0xb20 net/core/dev.c:7238
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8794 Comm: syz-executor.3 Not tainted 4.14.198-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+0x14b/0x1f1 lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.7+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 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:964
RIP: 0010:rollback_registered_many+0x80c/0xb20 net/core/dev.c:7224
RSP: 0018:ffff8880852b7308 EFLAGS: 00010297
RAX: ffff88809fa52e18 RBX: ffff8880852b7460 RCX: 0000000000000000
RDX: 1ffff11011ac51fe RSI: ffff888092b20b08 RDI: ffff88808d628f40
RBP: ffff8880852b7400 R08: ffff888092b20b28 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808d628f40
R13: dffffc0000000000 R14: ffff88808d629000 R15: ffff8880852b7358
 unregister_netdevice_many+0x3e/0x1f0 net/core/dev.c:8285
 rtnl_delete_link+0xb4/0x100 net/core/rtnetlink.c:2375
 rtnl_dellink+0x1b3/0x780 net/core/rtnetlink.c:2411
 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4316
 netlink_rcv_skb+0x12f/0x3b0 net/netlink/af_netlink.c:2433
 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4328
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x40b/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x657/0xc60 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xac/0xf0 net/socket.c:656
 ___sys_sendmsg+0x625/0x920 net/socket.c:2062
 __sys_sendmsg+0xc1/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0xd/0x20 net/socket.c:2103
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45d239
RSP: 002b:00007f06152bcc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000002c0c0 RCX: 000000000045d239
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000009
RBP: 000000000118d0c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118d08c
R13: 00007ffe75f05f6f R14: 00007f06152bd9c0 R15: 000000000118d08c
Kernel Offset: disabled
Rebooting in 86400 seconds..