KCSAN: data-race in vfs_readlink / vfs

KCSAN: data-race in vfs_readlink / vfs_unlink (2)
Status: moderation: reported on 2020/09/28 07:47
Reported-by: syzbot+d64a7b91f17b590f54c3@syzkaller.appspotmail.com
First crash: 292d, last: 1d04h

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in vfs_readlink / vfs_unlink				12	330d	493d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in vfs_readlink / vfs_unlink

write to 0xffff8880117519c0 of 4 bytes by task 23800 on cpu 0:
 dont_mount include/linux/dcache.h:357 [inline]
 vfs_unlink+0x289/0x3e0 fs/namei.c:4033
 do_unlinkat+0x29f/0x4f0 fs/namei.c:4098
 __do_sys_unlink fs/namei.c:4145 [inline]
 __se_sys_unlink fs/namei.c:4143 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4143
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8880117519c0 of 4 bytes by task 4836 on cpu 1:
 __d_entry_type include/linux/dcache.h:394 [inline]
 d_is_symlink include/linux/dcache.h:424 [inline]
 vfs_readlink+0x1c1/0x260 fs/namei.c:4798
 do_readlinkat+0x170/0x200 fs/stat.c:429
 __do_sys_readlink fs/stat.c:450 [inline]
 __se_sys_readlink fs/stat.c:447 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:447
 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: 4836 Comm: systemd-udevd Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (161):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/04/14 03:10	upstream	eebe426d	a184b83e	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/10 16:37	upstream	d4961772	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/09 21:37	upstream	17e7124a	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/09 05:52	upstream	3fb4f979	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/08 13:17	upstream	454859c5	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/06 20:49	upstream	2d743660	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/05 04:10	upstream	e49d033b	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/03 18:49	upstream	d93a0d43	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/02 03:03	upstream	ffd9fb54	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/04/01 04:44	upstream	d19cc4bf	6a81331a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/29 08:01	upstream	36a14638	a8529b82	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/27 05:07	upstream	0f4498ce	a8529b82	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/24 20:04	upstream	4ee998b0	607e3baf	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/23 08:40	upstream	84196390	8092f30d	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/22 05:11	upstream	5ee96fa9	bea32f74	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/16 19:19	upstream	1df27313	fdb2bb2c	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/16 12:04	upstream	1a4431a5	fdb2bb2c	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/15 10:34	upstream	1e28eed1	cc1cff8f	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/14 13:56	upstream	88fe4924	4a003785	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/12 23:49	upstream	f296bfd5	429d8a6b	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/11 07:39	upstream	a74e6a01	c2ca1f2a	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/10 21:13	upstream	05a59d79	764067f3	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/03/08 23:39	upstream	144c79ef	09fbf400	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/24 09:55	upstream	c03c21ba	fcc6d71b	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/18 06:51	upstream	f40ddce8	14052202	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/16 20:16	upstream	f40ddce8	98682e5e	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/14 07:57	upstream	ac30d8ce	98682e5e	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/13 04:37	upstream	dcc0b490	98682e5e	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/06 16:21	upstream	1e0d27fc	0655e081	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/06 04:19	upstream	1e0d27fc	23a562df	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/02/02 08:17	upstream	88bb507a	e6b95f32	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/28 22:23	upstream	e5ff2cb9	7df34f59	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/22 23:45	upstream	83d09ad4	52e37319	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/22 09:26	upstream	83d09ad4	d4f4eca5	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/20 23:27	upstream	75439bc4	d4f4eca5	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/20 09:29	upstream	45dfb8a5	d4f4eca5	.config	log	report	info	KCSAN: data-race in vfs_readlink / vfs_unlink
ci2-upstream-kcsan-gce	2021/01/17 10:02	upstream	0da0a8a0	813be542	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/17 01:23	upstream	54c6247d	65a7a854	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/15 06:41	upstream	14662050	65a7a854	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/13 23:45	upstream	65f0d241	269d24e8	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/12 08:07	upstream	a0d54b4f	2c1f2513	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/09 23:57	upstream	2ff90100	2c1f2513	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/07 22:56	upstream	f5e6c330	c104d4a3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/23 22:04	upstream	805c6d3c	54289b08	.config	log	report	info
ci2-upstream-kcsan-gce	2020/06/26 15:34	upstream	4a21185c	9506ea6d	.config	log	report