bisecting fixing commit since e3c1b27308ae0472f27e07903181d6abfe0cb1d7
building syzkaller on 55565fa0377f97cf09bfab365707e08b0156c11b
testing commit e3c1b27308ae0472f27e07903181d6abfe0cb1d7 with gcc (GCC) 8.1.0
kernel signature: eb06a426e39a3bc015583d6c2edbf2f496839871479703c78c3829e45576b273
all runs: crashed: WARNING in ovl_create_or_link
testing current HEAD 01364dad1d4577e27a57729d41053f661bb8a5b9
testing commit 01364dad1d4577e27a57729d41053f661bb8a5b9 with gcc (GCC) 8.1.0
kernel signature: 02e1d49d07ec16b38d2939fbf475b117a6d97360f4c3bddf8b043f61aff89ad3
all runs: crashed: WARNING in ovl_create_or_link
revisions tested: 2, total time: 23m1.965366275s (build: 16m4.649519177s, test: 6m5.364161166s)
the crash still happens on HEAD
commit msg: Linux 4.14.174
crash: WARNING in ovl_create_or_link
IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready
audit: type=1804 audit(1585629165.524:11): pid=6978 uid=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir578034840/syzkaller.XZB3Vm/0/file0/file0" dev="sda1" ino=15754 res=1
bridge0: port 2(bridge_slave_1) entered blocking state
------------[ cut here ]------------
bridge0: port 2(bridge_slave_1) entered forwarding state
WARNING: CPU: 1 PID: 6978 at fs/overlayfs/dir.c:523 ovl_create_or_link+0x545/0x13b0 fs/overlayfs/dir.c:523
Kernel panic - not syncing: panic_on_warn set ...

IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bond: link becomes ready
CPU: 1 PID: 6978 Comm: syz-executor.4 Not tainted 4.14.174-syzkaller #0
IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network
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
 __warn.cold.8+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:963
IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready
RIP: 0010:ovl_create_or_link+0x545/0x13b0 fs/overlayfs/dir.c:523
IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
RSP: 0018:ffff8880993e7b00 EFLAGS: 00010202
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
RAX: 0000000000000000 RBX: ffff88807e6515f0 RCX: ffff88807e650544
8021q: adding VLAN 0 to HW filter on device batadv0
RDX: 1ffff1100fcca2bf RSI: ffff888095a52c60 RDI: ffff88807e6515f8
RBP: ffff8880993e7cb8 R08: ffff888095a52c80 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff1101327cf6e R15: ffff88807e647550
 ovl_link+0x151/0x19d fs/overlayfs/dir.c:614
 vfs_link+0x646/0xa10 fs/namei.c:4264
 SYSC_linkat fs/namei.c:4332 [inline]
 SyS_linkat fs/namei.c:4288 [inline]
 SYSC_link fs/namei.c:4355 [inline]
 SyS_link+0x2f8/0x4b0 fs/namei.c:4353
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4597c9
RSP: 002b:00007f66ea482c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00000000004597c9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000020000140
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f66ea4836d4
R13: 00000000004f53e2 R14: 00000000004d9f08 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..