KCSAN: data-race in shmem_mknod / vfs_getattr

KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
Status: moderation: reported on 2020/08/02 14:16
Reported-by: syzbot+7a06fc3f1c23166f7c87@syzkaller.appspotmail.com
First crash: 404d, last: 14h55m

Sample crash report:

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

write to 0xffff8881060d8b40 of 8 bytes by task 7353 on cpu 0:
 shmem_mknod+0xdc/0x170 mm/shmem.c:2841
 shmem_create+0x2f/0x40 mm/shmem.c:2892
 lookup_open fs/namei.c:3228 [inline]
 open_last_lookups fs/namei.c:3298 [inline]
 path_openat+0xcd1/0x1f20 fs/namei.c:3504
 do_filp_open+0xe9/0x200 fs/namei.c:3534
 do_sys_openat2+0xa3/0x250 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_open fs/open.c:1228 [inline]
 __se_sys_open fs/open.c:1224 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1224
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881060d8b40 of 8 bytes by task 7357 on cpu 1:
 i_size_read include/linux/fs.h:849 [inline]
 generic_fillattr fs/stat.c:53 [inline]
 vfs_getattr_nosec+0x23d/0x2f0 fs/stat.c:108
 vfs_getattr fs/stat.c:142 [inline]
 vfs_statx+0x128/0x290 fs/stat.c:207
 vfs_fstatat fs/stat.c:225 [inline]
 vfs_stat include/linux/fs.h:3382 [inline]
 __do_sys_newstat fs/stat.c:367 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:363
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:363
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000002b70 -> 0x0000000000002b84

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7357 Comm: systemd-udevd Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (612):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/07/27 22:45	upstream	7d549995d4e0	17d6ab15	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/27 17:10	upstream	ff1176468d36	17d6ab15	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/26 08:21	upstream	ff1176468d36	fd511809	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/26 04:20	upstream	ff1176468d36	4d1b57d4	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/25 17:08	upstream	d8079fac1681	4d1b57d4	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/25 04:06	upstream	7ffca2bb9d8b	4d1b57d4	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/24 10:08	upstream	f0fddcec6b62	4d1b57d4	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/24 05:12	upstream	f0fddcec6b62	bc5f1d88	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/23 16:00	upstream	8baef6386baa	bc5f1d88	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/23 04:15	upstream	9bead1b58c4c	bc5f1d88	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/22 14:34	upstream	3d5895cd3517	241790bb	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/22 10:24	upstream	3d5895cd3517	29c3f20f	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/21 21:30	upstream	7b6ae471e541	29c3f20f	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/21 15:18	upstream	8cae8cd89f05	29c3f20f	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/20 15:32	upstream	8cae8cd89f05	1b201b48	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/20 01:04	upstream	2734d6c1b1a0	bc48c9ab	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/19 16:17	upstream	2734d6c1b1a0	e6a17580	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/18 21:01	upstream	f0eb870a8422	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/18 00:56	upstream	1d67c8d993ba	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/17 14:47	upstream	d980cc0620ae	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/17 01:33	upstream	0d18c12b288a	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/16 13:08	upstream	d936eb238744	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/15 23:33	upstream	dd9c7df94c1b	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/15 15:34	upstream	8096acd7442e	f115ae98	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/15 03:17	upstream	8096acd7442e	b9a2f64e	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/14 17:42	upstream	8096acd7442e	94e0b707	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/14 15:42	upstream	40226a3d96ef	94e0b707	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/14 01:19	upstream	40226a3d96ef	484502bd	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/13 20:25	upstream	40226a3d96ef	70168d5c	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/13 14:47	upstream	7fef2edf7cc7	70168d5c	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/12 21:32	upstream	7fef2edf7cc7	f415556d	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/12 05:24	upstream	e73f0f0ee754	a4869c92	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/11 22:07	upstream	98f7fdced2e0	8f5a7b8c	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/09 20:48	upstream	3dbdb38e2869	8f5a7b8c	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/09 11:33	upstream	3dbdb38e2869	281e815f	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/08 19:25	upstream	3dbdb38e2869	1b20171a	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/08 07:45	upstream	3dbdb38e2869	1aade754	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/07 22:27	upstream	3dbdb38e2869	95793bce	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/07 11:53	upstream	3dbdb38e2869	4846d5c1	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/06 19:23	upstream	3dbdb38e2869	cca78469	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/06 08:41	upstream	3dbdb38e2869	6c4484eb	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/02 17:18	upstream	3dbdb38e2869	55aa55c2	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/07/02 13:54	upstream	3dbdb38e2869	658ebc66	.config	log	report	info	KCSAN: data-race in shmem_mknod / vfs_getattr_nosec
ci2-upstream-kcsan-gce	2021/01/17 14:20	upstream	0da0a8a0a0e1	813be542	.config	log	report	info
ci2-upstream-kcsan-gce	2020/08/01 04:31	upstream	7dc6fd0f3b84	8df85ed9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/29 14:09	upstream	6ba1b005ffc3	19a8de55	.config	log	report
ci2-upstream-kcsan-gce	2020/06/18 15:50	upstream	1b5044021070	3ea11d3f	.config	log	report