KCSAN: data-race in __ext4_new_inode / find_next_zero

KCSAN: data-race in __ext4_new_inode / find_next_zero_bit (4)
Status: moderation: reported on 2020/06/26 17:19
Reported-by: syzbot+fb83855310e88185110c@syzkaller.appspotmail.com
First crash: 262d, last: 11h36m

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit	4	510d	520d	0/21	closed as invalid on 2019/10/15 15:50
upstream	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit (3)	106	388d	425d	0/21	auto-closed as invalid on 2020/04/23 13:26
upstream	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit (2)	37	474d	503d	0/21	closed as invalid on 2019/11/19 14:04

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __ext4_new_inode / find_next_zero_bit

write to 0xffff888108b272e8 of 8 bytes by task 8365 on cpu 1:
 instrument_write include/linux/instrumented.h:42 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:79 [inline]
 __test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:95 [inline]
 __test_and_set_bit_le include/asm-generic/bitops/le.h:90 [inline]
 __ext4_new_inode+0xe1b/0x2fe0 fs/ext4/ialloc.c:1093
 ext4_create+0x17c/0x310 fs/ext4/namei.c:2622
 lookup_open fs/namei.c:3219 [inline]
 open_last_lookups fs/namei.c:3289 [inline]
 path_openat+0xd36/0x21b0 fs/namei.c:3495
 do_filp_open+0xbd/0x1d0 fs/namei.c:3525
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_openat fs/open.c:1219 [inline]
 __se_sys_openat fs/open.c:1214 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1214
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888108b272e8 of 8 bytes by task 8390 on cpu 0:
 _find_next_bit lib/find_bit.c:60 [inline]
 find_next_zero_bit+0x80/0xf0 lib/find_bit.c:89
 find_next_zero_bit_le include/asm-generic/bitops/le.h:15 [inline]
 find_inode_bit+0x88/0x3a0 fs/ext4/ialloc.c:722
 __ext4_new_inode+0xb6c/0x2fe0 fs/ext4/ialloc.c:1063
 ext4_mkdir+0x28a/0x760 fs/ext4/namei.c:2804
 vfs_mkdir+0x135/0x1f0 fs/namei.c:3817
 do_mkdirat+0x147/0x230 fs/namei.c:3842
 __do_sys_mkdir fs/namei.c:3860 [inline]
 __se_sys_mkdir fs/namei.c:3858 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3858
 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: 0 PID: 8390 Comm: syz-executor.3 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1175):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/03/07 10:42	upstream	a38fd874	c599ed12	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/03/06 08:02	upstream	a38fd874	e4b4d570	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/03/04 20:00	upstream	cee407c5	f89ed068	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/03/04 17:04	upstream	f69d02e3	f89ed068	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/03/04 12:38	upstream	f69d02e3	d7e4e604	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/24 18:05	upstream	c03c21ba	fcc6d71b	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/23 19:04	upstream	3b9cdafb	fcc6d71b	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/23 09:23	upstream	b12b4724	fcc6d71b	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/22 11:08	upstream	31caf8b2	a659b3f1	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/21 18:45	upstream	55f62bc8	a659b3f1	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/21 05:18	upstream	e767b353	3e5ed8b4	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/20 10:33	upstream	f40ddce8	3e5ed8b4	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/19 15:03	upstream	f40ddce8	f689d40a	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/17 20:15	upstream	f40ddce8	14052202	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/17 08:25	upstream	f40ddce8	052f8d9f	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/15 02:40	upstream	f40ddce8	98682e5e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/14 11:36	upstream	358fecee	98682e5e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/13 22:24	upstream	ac30d8ce	98682e5e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/13 09:29	upstream	c6d8570e	98682e5e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/12 19:25	upstream	dcc0b490	98682e5e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/12 09:09	upstream	dcc0b490	a5f86b15	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/11 18:18	upstream	291009f6	a5f86b15	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/10 22:39	upstream	291009f6	a52ee10a	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/10 09:23	upstream	e0756cfc	9c8b8541	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/08 22:18	upstream	e0756cfc	2bd9619f	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/08 11:19	upstream	92bf2261	2ce644fc	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/07 22:19	upstream	b75dba7f	2ce644fc	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/07 08:34	upstream	825b5991	2ce644fc	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/06 23:56	upstream	964d069f	0655e081	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/06 15:05	upstream	1e0d27fc	0655e081	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/06 12:07	upstream	1e0d27fc	0655e081	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/06 02:41	upstream	1e0d27fc	23a562df	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/05 15:10	upstream	dd86e7fa	23a562df	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/05 02:14	upstream	5c279c4c	23a562df	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/05 02:13	upstream	5c279c4c	23a562df	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/04 14:07	upstream	61556703	42b90a7c	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/04 10:39	upstream	61556703	624dad51	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/03 21:35	upstream	3afe9076	624dad51	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/02 23:26	upstream	3aaf0a27	624dad51	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/02 08:59	upstream	88bb507a	19e09687	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/01 19:58	upstream	88bb507a	e6b95f32	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/01 13:13	upstream	1048ba83	e6b95f32	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/02/01 01:09	upstream	1048ba83	fc9fd31e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/01/31 11:59	upstream	6642d600	fc9fd31e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/01/30 22:39	upstream	8c947645	fc9fd31e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/01/30 08:42	upstream	0e9bcda5	fc9fd31e	.config	log	report	info	KCSAN: data-race in __ext4_new_inode / find_next_zero_bit
ci2-upstream-kcsan-gce	2021/01/17 10:08	upstream	0da0a8a0	813be542	.config	log	report	info
ci2-upstream-kcsan-gce	2020/06/26 14:55	upstream	4a21185c	9506ea6d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/26 02:30	upstream	4a21185c	aea82c00	.config	log	report
ci2-upstream-kcsan-gce	2020/06/18 14:06	upstream	1b504402	3ea11d3f	.config	log	report