bisecting fixing commit since 10d6aa565d0593fe4e152e49ab58f47a2952f902
building syzkaller on 6affd8e838ce8a0c7d72445a7f67fe3bde8bbe04
testing commit 10d6aa565d0593fe4e152e49ab58f47a2952f902 with gcc (GCC) 8.1.0
kernel signature: 0df5c7738752d33f14950256af19fbc6292b6991
all runs: crashed: WARNING in ovl_rename
testing current HEAD a844dc4c544291470aa69edbe2434b040794e269
testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0
kernel signature: 3941a5fbcc663278c5244c71b23581ab8c246c71
all runs: crashed: WARNING in ovl_rename
revisions tested: 2, total time: 33m45.29188482s (build: 16m2.898776501s, test: 16m43.324676468s)
the crash still happens on HEAD
commit msg: Linux 4.14.158
crash: WARNING in ovl_rename
overlayfs: workdir and upperdir must reside under the same mount
overlayfs: upper fs does not support tmpfile.
overlayfs: workdir and upperdir must reside under the same mount
overlayfs: upper fs does not support xattr.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 20011 at fs/overlayfs/dir.c:1045 ovl_rename+0xc79/0xfc0 fs/overlayfs/dir.c:1031
Kernel panic - not syncing: panic_on_warn set ...

overlayfs: workdir and upperdir must reside under the same mount
CPU: 0 PID: 20011 Comm: syz-executor.1 Not tainted 4.14.158-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
 __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
RIP: 0010:ovl_rename+0xc79/0xfc0 fs/overlayfs/dir.c:1045
RSP: 0018:ffff888090ee7a48 EFLAGS: 00010246
RAX: ffff8880839d1860 RBX: ffff888077a0be40 RCX: ffff88809a2f2840
RDX: dffffc0000000000 RSI: ffff88809a2f2840 RDI: ffff88809a2f2898
RBP: ffff888090ee7b50 R08: 0000000000000001 R09: 0000000000000000
R10: ffff888085a936e0 R11: ffff888093f3a8e0 R12: ffff888093f3a880
R13: ffff88809a2bfe00 R14: 1ffff110121dcf59 R15: 0000000000000000
 vfs_rename+0xc42/0x1630 fs/namei.c:4493
 SYSC_renameat2 fs/namei.c:4641 [inline]
 SyS_renameat2 fs/namei.c:4530 [inline]
 SYSC_rename fs/namei.c:4681 [inline]
 SyS_rename+0x494/0x700 fs/namei.c:4679
overlayfs: workdir and upperdir must reside under the same mount
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007ff8d48c8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000020000400
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff8d48c96d4
R13: 00000000004c6da0 R14: 00000000004dc138 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..