KCSAN: data-race in drop_nlink / vfs_getattr

KCSAN: data-race in drop_nlink / vfs_getattr_nosec
Status: auto-closed as invalid on 2021/04/21 10:41
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 215d, last: 215d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in drop_nlink / vfs_getattr_nosec (3)				2	76d	94d	0/22	auto-closed as invalid on 2021/09/07 16:42
upstream	KCSAN: data-race in drop_nlink / vfs_getattr_nosec (2)				6	142d	175d	0/22	auto-closed as invalid on 2021/07/03 10:04

Sample crash report:

==================================================================
BUG: KCSAN: data-race in drop_nlink / vfs_getattr_nosec

write to 0xffff88810a8bf798 of 4 bytes by task 22338 on cpu 1:
 drop_nlink+0x37/0x90 fs/inode.c:306
 shmem_rmdir+0x42/0x70 mm/shmem.c:2978
 vfs_rmdir+0x13b/0x2a0 fs/namei.c:3899
 do_rmdir+0x186/0x310 fs/namei.c:3962
 __do_sys_rmdir fs/namei.c:3980 [inline]
 __se_sys_rmdir fs/namei.c:3978 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3978
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810a8bf798 of 4 bytes by task 22345 on cpu 0:
 generic_fillattr fs/stat.c:49 [inline]
 vfs_getattr_nosec+0x203/0x340 fs/stat.c:100
 vfs_getattr fs/stat.c:134 [inline]
 vfs_statx+0x128/0x290 fs/stat.c:199
 vfs_fstatat fs/stat.c:217 [inline]
 vfs_stat include/linux/fs.h:3236 [inline]
 __do_sys_newstat fs/stat.c:359 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:355
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:355
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22345 Comm: systemd-udevd Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/03/17 10:38	upstream	1df27313f50a	fdb2bb2c	.config	log	report			info	KCSAN: data-race in drop_nlink / vfs_getattr_nosec