KCSAN: data-race in __dentry_kill / retain

KCSAN: data-race in __dentry_kill / retain_dentry (3)
Status: auto-closed as invalid on 2021/03/18 01:39
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 226d, last: 221d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __dentry_kill / retain_dentry (2)	12	272d	287d	0/22	auto-closed as invalid on 2021/01/26 06:19
upstream	KCSAN: data-race in __dentry_kill / retain_dentry (4)	3	163d	182d	0/22	auto-closed as invalid on 2021/05/17 09:01
upstream	KCSAN: data-race in __dentry_kill / retain_dentry	1	433d	433d	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 0xffff88810f1cd6c0 of 4 bytes by task 16170 on cpu 1:
 retain_dentry+0x1de/0x260 fs/dcache.c:659
 dput+0x10e/0x420 fs/dcache.c:880
 __fput+0x3ae/0x4e0 fs/file_table.c:293
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x17c/0x1b0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:294
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810f1cd6c0 of 4 bytes by task 16164 on cpu 0:
 dentry_unlist fs/dcache.c:544 [inline]
 __dentry_kill+0x1ef/0x450 fs/dcache.c:575
 dentry_kill fs/dcache.c:692 [inline]
 dput+0x208/0x420 fs/dcache.c:885
 handle_mounts fs/namei.c:1389 [inline]
 step_into+0x444/0xeb0 fs/namei.c:1691
 walk_component+0x190/0x350 fs/namei.c:1867
 lookup_last fs/namei.c:2312 [inline]
 path_lookupat+0x12d/0x560 fs/namei.c:2336
 filename_lookup+0xf2/0x380 fs/namei.c:2369
 user_path_at_empty+0x3b/0x50 fs/namei.c:2649
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:185
 vfs_fstatat fs/stat.c:207 [inline]
 vfs_lstat include/linux/fs.h:3122 [inline]
 __do_sys_newlstat fs/stat.c:362 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:356
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:356
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16164 Comm: systemd-udevd Not tainted 5.11.0-rc7-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	2021/02/11 01:35	upstream	291009f656e8	a52ee10a	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry
ci2-upstream-kcsan-gce	2021/02/07 10:50	upstream	825b5991a46e	2ce644fc	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry
ci2-upstream-kcsan-gce	2021/02/06 05:37	upstream	1e0d27fce010	23a562df	.config	log	report	info	KCSAN: data-race in __dentry_kill / retain_dentry