KCSAN: data-race in step_into / vfs

KCSAN: data-race in step_into / vfs_rename (3)
Status: auto-closed as invalid on 2020/11/24 01:44
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 310d, last: 277d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in step_into / vfs_rename	2	403d	453d	0/22	closed as invalid on 2020/06/18 14:24
upstream	KCSAN: data-race in step_into / vfs_rename (2)	1	395d	395d	0/22	auto-closed as invalid on 2020/07/29 00:43
upstream	KCSAN: data-race in step_into / vfs_rename (4)	1	205d	205d	0/22	auto-closed as invalid on 2021/02/04 02:28

Sample crash report:

loop5: partition table partially beyond EOD, truncated
loop5: p1 start 335741103 is beyond EOD, truncated
loop5: p2 size 2 extends beyond EOD, truncated
==================================================================
BUG: KCSAN: data-race in step_into / vfs_rename

read-write to 0xffff88810be7bc00 of 4 bytes by task 10396 on cpu 1:
 dont_mount include/linux/dcache.h:354 [inline]
 vfs_rename+0xcd9/0xe20 fs/namei.c:4319
 do_renameat2+0x56c/0x930 fs/namei.c:4456
 __do_sys_rename fs/namei.c:4502 [inline]
 __se_sys_rename fs/namei.c:4500 [inline]
 __x64_sys_rename+0x3a/0x40 fs/namei.c:4500
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810be7bc00 of 4 bytes by task 5077 on cpu 0:
 __d_entry_type include/linux/dcache.h:391 [inline]
 d_is_symlink include/linux/dcache.h:421 [inline]
 step_into+0x158/0xe40 fs/namei.c:1694
 open_last_lookups fs/namei.c:3200 [inline]
 path_openat+0xfdb/0x20a0 fs/namei.c:3365
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0xa3/0x240 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: 0 PID: 5077 Comm: systemd-udevd Not tainted 5.9.0-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	VM info
ci2-upstream-kcsan-gce	2020/10/20 01:41	upstream	bbe85027ce80	ff4a3345	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/22 08:27	upstream	98477740630f	3e8f6c27	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 13:00	upstream	5925fa68fe82	8247808b	.config	log	report	info