KCSAN: data-race in fuse_get_req / fuse_set

KCSAN: data-race in fuse_get_req / fuse_set_initialized (3)
Status: auto-closed as invalid on 2021/05/14 08:29
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 127d, last: 105d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in fuse_get_req / fuse_set_initialized (2)				10	165d	228d	0/22	auto-closed as invalid on 2021/03/14 23:46
upstream	KCSAN: data-race in fuse_get_req / fuse_set_initialized				8	559d	635d	0/22	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 0xffff88813613a304 of 4 bytes by task 14462 on cpu 0:
 fuse_set_initialized+0x15/0x30 fs/fuse/dev.c:82
 process_init_reply+0xdf/0xbc0 fs/fuse/inode.c:1075
 fuse_request_end+0x78b/0x7c0 fs/fuse/dev.c:332
 fuse_dev_do_write+0xc30/0xe50 fs/fuse/dev.c:1917
 fuse_dev_write+0x98/0xe0 fs/fuse/dev.c:1939
 call_write_iter include/linux/fs.h:1977 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x6f9/0x7e0 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+0x44/0xae

read to 0xffff88813613a304 of 4 bytes by task 14448 on cpu 1:
 fuse_block_alloc fs/fuse/dev.c:87 [inline]
 fuse_get_req+0x15d/0x580 fs/fuse/dev.c:115
 fuse_simple_request+0x83/0xde0 fs/fuse/dev.c:504
 fuse_lookup_name+0x153/0x3b0 fs/fuse/dir.c:428
 fuse_lookup+0x9b/0x2b0 fs/fuse/dir.c:469
 __lookup_slow+0x181/0x250 fs/namei.c:1630
 lookup_slow fs/namei.c:1647 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1943
 link_path_walk+0x4ba/0x780 fs/namei.c:2266
 path_lookupat+0x7b/0x570 fs/namei.c:2421
 filename_lookup+0xff/0x390 fs/namei.c:2455
 user_path_at_empty+0x3b/0x50 fs/namei.c:2735
 user_path_at include/linux/namei.h:60 [inline]
 do_mount fs/namespace.c:3243 [inline]
 __do_sys_mount fs/namespace.c:3454 [inline]
 __se_sys_mount+0x209/0x2e0 fs/namespace.c:3431
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3431
 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: 14448 Comm: syz-executor.3 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/04/09 08:21	upstream	3fb4f979b4fa	6a81331a	.config	log	report	info	KCSAN: data-race in fuse_get_req / fuse_set_initialized
ci2-upstream-kcsan-gce	2021/04/06 10:04	upstream	0a50438c8436	6a81331a	.config	log	report	info	KCSAN: data-race in fuse_get_req / fuse_set_initialized
ci2-upstream-kcsan-gce	2021/04/05 09:11	upstream	e49d033bddf5	6a81331a	.config	log	report	info	KCSAN: data-race in fuse_get_req / fuse_set_initialized
ci2-upstream-kcsan-gce	2021/03/18 01:42	upstream	6417f03132a6	fdb2bb2c	.config	log	report	info	KCSAN: data-race in fuse_get_req / fuse_set_initialized