KCSAN: data-race in __dentry_kill / retain

KCSAN: data-race in __dentry_kill / retain_dentry (4)
Status: auto-closed as invalid on 2021/05/17 09:01
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 183d, last: 164d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __dentry_kill / retain_dentry (3)	3	223d	227d	0/22	auto-closed as invalid on 2021/03/18 01:39
upstream	KCSAN: data-race in __dentry_kill / retain_dentry (2)	12	273d	288d	0/22	auto-closed as invalid on 2021/01/26 06:19
upstream	KCSAN: data-race in __dentry_kill / retain_dentry	1	434d	434d	0/22	auto-closed as invalid on 2020/08/18 17:44

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __dentry_kill / retain_dentry

write to 0xffff888025108cc0 of 4 bytes by task 32580 on cpu 0:
 d_lru_add fs/dcache.c:400 [inline]
 retain_dentry+0x199/0x260 fs/dcache.c:658
 dput+0x11e/0x430 fs/dcache.c:881
 path_put+0x1b/0x30 fs/namei.c:546
 vfs_statx+0x1fd/0x290 fs/stat.c:205
 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

read to 0xffff888025108cc0 of 4 bytes by task 4837 on cpu 1:
 dentry_unlist fs/dcache.c:545 [inline]
 __dentry_kill+0x1ef/0x450 fs/dcache.c:576
 dentry_kill fs/dcache.c:693 [inline]
 dput+0x218/0x430 fs/dcache.c:886
 handle_mounts fs/namei.c:1475 [inline]
 step_into+0x442/0xec0 fs/namei.c:1773
 walk_component+0x190/0x350 fs/namei.c:1949
 lookup_last fs/namei.c:2398 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2422
 filename_lookup+0xff/0x390 fs/namei.c:2455
 user_path_at_empty+0x3b/0x50 fs/namei.c:2735
 user_path_at include/linux/namei.h:60 [inline]
 do_faccessat+0x260/0x510 fs/open.c:425
 __do_sys_access fs/open.c:484 [inline]
 __se_sys_access fs/open.c:482 [inline]
 __x64_sys_access+0x33/0x40 fs/open.c:482
 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: 1 PID: 4837 Comm: systemd-udevd Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/04/10 06:41	upstream	4e04e7513b0f	6a81331a	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry
ci2-upstream-kcsan-gce	2021/04/02 22:56	upstream	1678e493d530	6a81331a	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry
ci2-upstream-kcsan-gce	2021/03/22 14:39	upstream	5ee96fa9dd78	bea32f74	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry