syzbot


KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit (4)

Status: auto-closed as invalid on 2022/03/31 12:11
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 281d, last: 281d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit (5) 1 228d 228d 0/24 auto-closed as invalid on 2022/05/23 18:19
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit 2 985d 1020d 0/24 auto-closed as invalid on 2020/05/31 09:34
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit (3) 1 390d 390d 0/24 auto-closed as invalid on 2021/12/12 14:17
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit (2) 3 806d 846d 0/24 auto-closed as invalid on 2020/10/22 16:12

Sample crash report:
==================================================================
BUG: KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit

write to 0xffff888237d1e0b4 of 1 bytes by task 0 on cpu 1:
 tick_nohz_idle_exit+0xac/0x2a0 kernel/time/tick-sched.c:1292
 do_idle+0x21d/0x250 kernel/sched/idle.c:319
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403
 secondary_startup_64_no_verify+0xc4/0xcb

read to 0xffff888237d1e0b4 of 1 bytes by task 5033 on cpu 0:
 get_cpu_iowait_time_us+0x6b/0x1f0
 get_iowait_time fs/proc/stat.c:70 [inline]
 show_stat+0x91f/0xdd0 fs/proc/stat.c:176
 seq_read_iter+0x2e1/0x930 fs/seq_file.c:230
 proc_reg_read_iter+0xd6/0x170 fs/proc/inode.c:296
 call_read_iter include/linux/fs.h:2068 [inline]
 io_iter_do_read fs/io_uring.c:3611 [inline]
 io_read fs/io_uring.c:3668 [inline]
 io_issue_sqe+0xb34/0x9610 fs/io_uring.c:6750
 __io_queue_sqe+0x20/0x6a0 fs/io_uring.c:7097
 io_queue_sqe+0x46/0x550 fs/io_uring.c:7139
 io_submit_sqe+0x796/0x4b34 fs/io_uring.c:7347
 io_submit_sqes+0x25f/0x560 fs/io_uring.c:7453
 __do_sys_io_uring_enter fs/io_uring.c:10152 [inline]
 __se_sys_io_uring_enter+0x212/0xb00 fs/io_uring.c:10094
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10094
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5033 Comm: syz-executor.5 Not tainted 5.17.0-rc5-syzkaller-00021-g23d04328444a-dirty #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 2022/02/24 12:05 upstream 23d04328444a 6e821dbf .config log report info KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit
* Struck through repros no longer work on HEAD.