KCSAN: data-race in __dentry_kill / d_set_d

KCSAN: data-race in __dentry_kill / d_set_d_op (7)
Status: auto-closed as invalid on 2021/07/19 11:09
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 132d, last: 98d

similar bugs (6):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (3)	6	471d	511d	0/22	closed as invalid on 2020/06/18 14:24
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (2)	9	600d	669d	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	319d	287d	0/22	auto-closed as invalid on 2020/12/21 11:58
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (4)	3	400d	419d	0/22	auto-closed as invalid on 2020/09/21 06:01
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op (6)	1	190d	190d	0/22	auto-closed as invalid on 2021/04/18 21:16
upstream	KCSAN: data-race in __dentry_kill / d_set_d_op	3	680d	687d	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 0xffff888106668480 of 4 bytes by task 7335 on cpu 0:
 d_set_d_op+0x17f/0x220 fs/dcache.c:1910
 simple_lookup+0x78/0x90 fs/libfs.c:74
 lookup_open fs/namei.c:3193 [inline]
 open_last_lookups fs/namei.c:3285 [inline]
 path_openat+0xb5a/0x20b0 fs/namei.c:3491
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106668480 of 4 bytes by task 7310 on cpu 1:
 dentry_unlist fs/dcache.c:547 [inline]
 __dentry_kill+0x1ef/0x4e0 fs/dcache.c:578
 dentry_kill fs/dcache.c:695 [inline]
 dput+0xc6/0x360 fs/dcache.c:888
 handle_mounts fs/namei.c:1474 [inline]
 step_into+0x442/0xec0 fs/namei.c:1772
 open_last_lookups fs/namei.c:3308 [inline]
 path_openat+0xfc8/0x20b0 fs/namei.c:3491
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x10000000 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7310 Comm: systemd-udevd Not tainted 5.13.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/06/14 11:05	upstream	009c9aa5be65	1ba81399	.config	log	report			info	KCSAN: data-race in __dentry_kill / d_set_d_op
ci2-upstream-kcsan-gce	2021/05/12 03:56	upstream	88b06399c9c7	b3c3bb8e	.config	log	report			info	KCSAN: data-race in __dentry_kill / d_set_d_op