==================================================================
BUG: KCSAN: data-race in lookup_fast / vfs_unlink

read to 0xffff8881248ab300 of 4 bytes by task 3891 on cpu 1:
 d_is_miss include/linux/dcache.h:394 [inline]
 d_is_negative include/linux/dcache.h:440 [inline]
 lookup_fast+0xdf/0x700 fs/namei.c:1575
 walk_component+0x6d/0xe80 fs/namei.c:1796
 lookup_last fs/namei.c:2263 [inline]
 path_lookupat.isra.0+0x13a/0x5a0 fs/namei.c:2308
 filename_lookup+0x145/0x2b0 fs/namei.c:2338
 user_path_at_empty+0x4c/0x70 fs/namei.c:2598
 do_readlinkat+0x84/0x220 fs/stat.c:399
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881248ab300 of 4 bytes by task 7293 on cpu 0:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x26a/0x3e0 fs/namei.c:3993
 do_unlinkat+0x32b/0x530 fs/namei.c:4055
 __do_sys_unlink fs/namei.c:4102 [inline]
 __se_sys_unlink fs/namei.c:4100 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4100
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7293 Comm: udevd Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7293 Comm: udevd Not tainted 5.4.0-rc3+ #0
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+0xf5/0x159 lib/dump_stack.c:113
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0x10 kernel/kcsan/report.c:302
 __kcsan_setup_watchpoint+0x32e/0x4a0 kernel/kcsan/core.c:411
 __tsan_write4 kernel/kcsan/kcsan.c:35 [inline]
 __tsan_write4+0x32/0x40 kernel/kcsan/kcsan.c:35
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x26a/0x3e0 fs/namei.c:3993
 do_unlinkat+0x32b/0x530 fs/namei.c:4055
 __do_sys_unlink fs/namei.c:4102 [inline]
 __se_sys_unlink fs/namei.c:4100 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4100
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fdd21d4c5d7
Code: 48 3d 00 f0 ff ff 77 03 48 98 c3 48 8b 15 59 38 2b 00 f7 d8 64 89 02 48 83 c8 ff c3 90 90 90 90 90 90 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 38 2b 00 31 d2 48 29 c2 64
RSP: 002b:00007ffea361d7b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00000000015bd590 RCX: 00007fdd21d4c5d7
RDX: 00007ffea361d7e4 RSI: 000000000041cce6 RDI: 00007ffea361d7d0
RBP: 00000000015b8250 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000064f
R13: 0000000000625500 R14: 00000000015b8250 R15: 000000000000000b
Kernel Offset: disabled
Rebooting in 86400 seconds..