KCSAN: data-race in binder_dec_node_nilocked / binder_state

KCSAN: data-race in binder_dec_node_nilocked / binder_state_show (3)
Status: auto-closed as invalid on 2020/07/26 15:33
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 493d, last: 493d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in binder_dec_node_nilocked / binder_state_show				1	631d	572d	0/22	auto-closed as invalid on 2020/04/17 15:24
upstream	KCSAN: data-race in binder_dec_node_nilocked / binder_state_show (2)				3	504d	539d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in binder_dec_node_nilocked / binder_state_show

write to 0xffff88812240bb54 of 4 bytes by task 11925 on cpu 1:
 binder_state_show+0xae/0x300 drivers/android/binder.c:5949
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 full_proxy_read+0xaf/0x140 fs/debugfs/file.c:229
 do_loop_readv_writev fs/read_write.c:715 [inline]
 do_iter_read+0x3f5/0x480 fs/read_write.c:936
 vfs_readv fs/read_write.c:1054 [inline]
 do_preadv+0x13b/0x230 fs/read_write.c:1146
 __do_sys_preadv fs/read_write.c:1196 [inline]
 __se_sys_preadv fs/read_write.c:1191 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1191
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812240bb54 of 4 bytes by task 11922 on cpu 0:
 binder_dec_node_nilocked+0x178/0x680 drivers/android/binder.c:1261
 binder_dec_node_tmpref+0x18e/0x350 drivers/android/binder.c:1379
 binder_put_node drivers/android/binder.c:1387 [inline]
 binder_state_show+0x277/0x300 drivers/android/binder.c:5961
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 full_proxy_read+0xaf/0x140 fs/debugfs/file.c:229
 do_loop_readv_writev fs/read_write.c:715 [inline]
 do_iter_read+0x3f5/0x480 fs/read_write.c:936
 vfs_readv fs/read_write.c:1054 [inline]
 do_preadv+0x13b/0x230 fs/read_write.c:1146
 __do_sys_preadv fs/read_write.c:1196 [inline]
 __se_sys_preadv fs/read_write.c:1191 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1191
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11922 Comm: syz-executor.2 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/06/21 15:29	upstream	64677779e896	4f2acff9	.config	log	report