syzbot


KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter (5)

Status: auto-closed as invalid on 2022/06/22 15:45
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 194d, last: 194d
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_enter (2) 8 757d 721d 0/24 auto-closed as invalid on 2020/12/21 11:40
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter (3) 1 451d 451d 0/24 auto-closed as invalid on 2021/10/09 06:41
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter 9 913d 1031d 0/24 closed as invalid on 2020/06/18 14:24
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter (4) 12 291d 394d 0/24 auto-closed as invalid on 2022/03/17 13:24

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

read-write to 0xffff888237d1e0b4 of 1 bytes by task 0 on cpu 1:
 tick_nohz_idle_enter+0x6c/0xc0 kernel/time/tick-sched.c:1158
 do_idle+0x3d/0x250 kernel/sched/idle.c:277
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 start_secondary+0x78/0x80 arch/x86/kernel/smpboot.c:266
 secondary_startup_64_no_verify+0xc4/0xcb

read to 0xffff888237d1e0b4 of 1 bytes by task 23862 on cpu 0:
 get_cpu_iowait_time_us+0x68/0x1d0
 get_iowait_time fs/proc/stat.c:70 [inline]
 show_stat+0x9de/0xe60 fs/proc/stat.c:176
 seq_read_iter+0x2c3/0x8e0 fs/seq_file.c:230
 proc_reg_read_iter+0xd4/0x170 fs/proc/inode.c:296
 call_read_iter include/linux/fs.h:2044 [inline]
 io_iter_do_read fs/io_uring.c:3742 [inline]
 io_read fs/io_uring.c:3861 [inline]
 io_issue_sqe+0x1bd3/0x8690 fs/io_uring.c:7143
 __io_queue_sqe fs/io_uring.c:7512 [inline]
 io_queue_sqe fs/io_uring.c:7554 [inline]
 io_submit_sqe+0x65d/0x4300 fs/io_uring.c:7759
 io_submit_sqes+0x25e/0x7e0 fs/io_uring.c:7865
 __do_sys_io_uring_enter fs/io_uring.c:10810 [inline]
 __se_sys_io_uring_enter+0x2cb/0xc70 fs/io_uring.c:10736
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10736
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x08 -> 0x0d

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23862 Comm: syz-executor.4 Not tainted 5.18.0-rc7-syzkaller-00006-g210e04ff7681-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 2022/05/18 15:41 upstream 210e04ff7681 50c53f39 .config log report info KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter
* Struck through repros no longer work on HEAD.