KCSAN: data-race in fuse_get_req / fuse_set

KCSAN: data-race in fuse_get_req / fuse_set_initialized (2)
Status: moderation: reported on 2020/12/07 11:41
Reported-by: syzbot+9cdf8302f991d9f3379b@syzkaller.appspotmail.com
First crash: 158d, last: 11d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in fuse_get_req / fuse_set_initialized				8	380d	456d	0/17	auto-closed as invalid on 2020/03/20 23:57

Sample crash report:

==================================================================
BUG: KCSAN: data-race in fuse_get_req / fuse_set_initialized

write to 0xffff88810aee1104 of 4 bytes by task 10014 on cpu 0:
 fuse_set_initialized+0x15/0x30 fs/fuse/dev.c:82
 process_init_reply+0xdf/0xbb0 fs/fuse/inode.c:1075
 fuse_request_end+0x764/0x7a0 fs/fuse/dev.c:332
 fuse_dev_do_write+0xba1/0xe40 fs/fuse/dev.c:1921
 fuse_dev_write+0x98/0xe0 fs/fuse/dev.c:1943
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x6d4/0x7c0 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810aee1104 of 4 bytes by task 10005 on cpu 1:
 fuse_block_alloc fs/fuse/dev.c:87 [inline]
 fuse_get_req+0xfd/0x520 fs/fuse/dev.c:115
 fuse_simple_request+0x83/0xdd0 fs/fuse/dev.c:504
 fuse_lookup_name+0x153/0x3b0 fs/fuse/dir.c:428
 fuse_lookup+0x99/0x2b0 fs/fuse/dir.c:469
 __lookup_slow+0x181/0x250 fs/namei.c:1544
 lookup_slow fs/namei.c:1561 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1861
 lookup_last fs/namei.c:2312 [inline]
 path_lookupat+0x11d/0x550 fs/namei.c:2336
 filename_lookup+0xf2/0x380 fs/namei.c:2369
 user_path_at_empty+0x3b/0x50 fs/namei.c:2649
 user_path_at include/linux/namei.h:59 [inline]
 ksys_umount fs/namespace.c:1754 [inline]
 __do_sys_umount fs/namespace.c:1762 [inline]
 __se_sys_umount fs/namespace.c:1760 [inline]
 __x64_sys_umount+0x65/0xb0 fs/namespace.c:1760
 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: 1 PID: 10005 Comm: syz-executor.3 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (9):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/13 13:06	upstream	e609571b	a945f0a3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/12/17 17:05	upstream	accefff5	04201c06	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/11/15 04:11	upstream	e28c0d7c	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/10/17 01:16	upstream	54a4c789	6e262c73	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/10/10 21:25	upstream	6f2f486d	4a77ae0b	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/09/18 19:05	upstream	10b82d51	38962c8b	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/09/03 18:16	upstream	e28f0104	abf9ba4f	.config	log	report		linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/08/28 18:31	upstream	15bc20c6	d5a3ae1f	.config	log	report		linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu
ci2-upstream-kcsan-gce	2020/08/19 17:40	upstream	18445bf4	db787902	.config	log	report		linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu