syzbot


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

Status: auto-closed as invalid on 2022/05/23 18:19
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 233d, last: 233d
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 2 990d 1025d 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 395d 395d 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 811d 851d 0/24 auto-closed as invalid on 2020/10/22 16:12
upstream KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_exit (4) 1 286d 286d 0/24 auto-closed as invalid on 2022/03/31 12:11

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

read-write to 0xffff888237c1e0b4 of 1 bytes by task 0 on cpu 0:
 tick_nohz_idle_exit+0xa4/0x280 kernel/time/tick-sched.c:1337
 do_idle+0x21d/0x250 kernel/sched/idle.c:316
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 rest_init+0xed/0xf0 init/main.c:726
 arch_call_rest_init+0xa/0xb init/main.c:882
 start_kernel+0x5e4/0x669 init/main.c:1140
 secondary_startup_64_no_verify+0xc4/0xcb

read to 0xffff888237c1e0b4 of 1 bytes by task 16762 on cpu 1:
 get_cpu_iowait_time_us+0x68/0x1d0
 get_iowait_time fs/proc/stat.c:70 [inline]
 show_stat+0x37f/0xe60 fs/proc/stat.c:135
 traverse+0x150/0x3b0 fs/seq_file.c:111
 seq_read_iter+0x824/0x8e0 fs/seq_file.c:195
 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:3743 [inline]
 io_read fs/io_uring.c:3859 [inline]
 io_issue_sqe+0x1bd3/0x8670 fs/io_uring.c:7130
 __io_queue_sqe fs/io_uring.c:7499 [inline]
 io_queue_sqe fs/io_uring.c:7541 [inline]
 io_submit_sqe+0x65d/0x4250 fs/io_uring.c:7746
 io_submit_sqes+0x25e/0x7e0 fs/io_uring.c:7852
 __do_sys_io_uring_enter fs/io_uring.c:10797 [inline]
 __se_sys_io_uring_enter+0x2cb/0xc70 fs/io_uring.c:10723
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10723
 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: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16762 Comm: syz-executor.5 Tainted: G        W         5.18.0-rc3-syzkaller-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 2022/04/18 18:07 upstream b2d229d4ddb1 8bcc32a6 .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.