KCSAN: data-race in __dentry_kill / d_set_d

KCSAN: data-race in __dentry_kill / d_set_d_op (4)
Status: auto-closed as invalid on 2020/09/21 06:01
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 366d, last: 347d

similar bugs (6):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (7)	2	45d	79d	0/22	auto-closed as invalid on 2021/07/19 11:09
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (3)	6	417d	458d	0/22	closed as invalid on 2020/06/18 14:24
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (2)	9	547d	616d	0/22	auto-closed as invalid on 2020/04/08 20:57
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (5)	1	266d	234d	0/22	auto-closed as invalid on 2020/12/21 11:58
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (6)	1	137d	137d	0/22	auto-closed as invalid on 2021/04/18 21:16
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op	3	627d	634d	0/22	closed as invalid on 2019/11/19 14:14

Sample crash report:

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

write to 0xffff88808eabc000 of 4 bytes by task 28915 on cpu 0:
 d_set_d_op+0x17f/0x220 fs/dcache.c:1875
 simple_lookup+0x78/0x90 fs/libfs.c:71
 __lookup_slow+0x182/0x250 fs/namei.c:1544
 lookup_slow fs/namei.c:1561 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1860
 lookup_last fs/namei.c:2309 [inline]
 path_lookupat+0x12d/0x560 fs/namei.c:2333
 filename_lookup+0xf2/0x380 fs/namei.c:2366
 user_path_at_empty+0x3b/0x50 fs/namei.c:2646
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0xb8/0x2b0 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3175 [inline]
 __do_sys_newlstat fs/stat.c:374 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:368
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:368
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88808eabc000 of 4 bytes by task 28996 on cpu 1:
 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:878
 handle_mounts fs/namei.c:1389 [inline]
 step_into+0x448/0xe70 fs/namei.c:1690
 open_last_lookups fs/namei.c:3200 [inline]
 path_openat+0xfaf/0x20a0 fs/namei.c:3365
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1188
 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: 1 PID: 28996 Comm: systemd-udevd Not tainted 5.8.0-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
ci2-upstream-kcsan-gce	2020/08/17 05:59	upstream	2cc3c4b3c2e9	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/11 11:07	upstream	00e4db51259a	5d3ebca9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/29 07:04	upstream	6ba1b005ffc3	19a8de55	.config	log	report