KCSAN: data-race in hrtimer_reprogram / print

KCSAN: data-race in hrtimer_reprogram / print_cpu (2)
Status: auto-closed as invalid on 2020/10/08 05:09
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 330d, last: 330d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in hrtimer_reprogram / print_cpu				1	496d	496d	0/22	auto-closed as invalid on 2020/05/29 16:43

Sample crash report:

==================================================================
BUG: KCSAN: data-race in hrtimer_reprogram / print_cpu

write to 0xffff88812c11ec20 of 8 bytes by task 8710 on cpu 1:
 hrtimer_reprogram+0x1dd/0x250 kernel/time/hrtimer.c:840
 hrtimer_start_range_ns+0x1f7/0x250 kernel/time/hrtimer.c:1138
 hrtimer_start_expires include/linux/hrtimer.h:436 [inline]
 hrtimer_sleeper_start_expires kernel/time/hrtimer.c:1804 [inline]
 do_nanosleep+0xd2/0x3a0 kernel/time/hrtimer.c:1880
 hrtimer_nanosleep kernel/time/hrtimer.c:1936 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1970 [inline]
 __se_sys_nanosleep+0x20b/0x2a0 kernel/time/hrtimer.c:1957
 __x64_sys_nanosleep+0x2d/0x40 kernel/time/hrtimer.c:1957
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812c11ec20 of 8 bytes by task 2399 on cpu 0:
 print_cpu+0x479/0x7f0 kernel/time/timer_list.c:148
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:311
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 pde_read fs/proc/inode.c:306 [inline]
 proc_reg_read+0x116/0x1a0 fs/proc/inode.c:318
 vfs_read+0x16d/0x5e0 fs/read_write.c:479
 ksys_read+0xce/0x180 fs/read_write.c:607
 __do_sys_read fs/read_write.c:617 [inline]
 __se_sys_read fs/read_write.c:615 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:615
 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: 2399 Comm: syz-executor.3 Not tainted 5.9.0-rc3-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	2020/09/03 05:00	upstream	fc3abb53250a	abf9ba4f	.config	log	report