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

read to 0xffff8881251d9c00 of 4 bytes by task 3991 on cpu 0:
 d_is_symlink include/linux/dcache.h:419 [inline]
 vfs_readlink+0x1bf/0x270 fs/namei.c:4730
 do_readlinkat+0x1f1/0x220 fs/stat.c:411
 __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/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881251d9c00 of 4 bytes by task 31756 on cpu 1:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x26a/0x3e0 fs/namei.c:4005
 do_unlinkat+0x32b/0x530 fs/namei.c:4067
 __do_sys_unlink fs/namei.c:4114 [inline]
 __se_sys_unlink fs/namei.c:4112 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4112
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31756 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 31756 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #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+0x11d/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:313
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:416
 check_access kernel/kcsan/core.c:459 [inline]
 __tsan_unaligned_write4+0xc7/0x110 kernel/kcsan/core.c:588
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x26a/0x3e0 fs/namei.c:4005
 do_unlinkat+0x32b/0x530 fs/namei.c:4067
 __do_sys_unlink fs/namei.c:4114 [inline]
 __se_sys_unlink fs/namei.c:4112 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4112
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4f64eaf5d7
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:00007ffc2912a1e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000c48460 RCX: 00007f4f64eaf5d7
RDX: 00007ffc2912a214 RSI: 000000000041cce6 RDI: 00007ffc2912a200
RBP: 0000000000c38250 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000002434
R13: 0000000000625500 R14: 0000000000c38250 R15: 000000000000000b
Kernel Offset: disabled
Rebooting in 86400 seconds..