syzbot


KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (6)

Status: auto-closed as invalid on 2022/08/21 13:12
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 142d, last: 142d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (5) 2 221d 247d 0/24 auto-closed as invalid on 2022/06/02 15:56
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter 10 922d 1045d 0/24 closed as invalid on 2020/06/18 14:24
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (3) 10 776d 833d 0/24 auto-closed as invalid on 2020/11/24 16:04
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (4) 14 307d 407d 0/24 auto-closed as invalid on 2022/03/09 00:14
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (2) 2 884d 897d 0/24 auto-closed as invalid on 2020/08/09 00:56

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

read-write to 0xffff888237d1e07c of 1 bytes by task 0 on cpu 1:
 tick_nohz_idle_enter+0x6c/0xc0 kernel/time/tick-sched.c:1159
 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+0xcf/0xdb

read to 0xffff888237d1e07c of 1 bytes by task 12510 on cpu 0:
 get_cpu_idle_time_us+0x68/0x1d0
 get_idle_time fs/proc/stat.c:54 [inline]
 show_stat+0x97e/0xe60 fs/proc/stat.c:175
 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:2052 [inline]
 io_iter_do_read fs/io_uring.c:4249 [inline]
 io_read fs/io_uring.c:4369 [inline]
 io_issue_sqe+0x23a3/0xaac0 fs/io_uring.c:8337
 io_queue_sqe fs/io_uring.c:8721 [inline]
 io_submit_sqe+0x2e20/0x3f50 fs/io_uring.c:8985
 io_submit_sqes+0x27b/0x500 fs/io_uring.c:9096
 __do_sys_io_uring_enter fs/io_uring.c:12043 [inline]
 __se_sys_io_uring_enter+0x24b/0xd60 fs/io_uring.c:11969
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:11969
 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+0x63/0xcd

value changed: 0x00 -> 0x05

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12510 Comm: syz-executor.2 Not tainted 5.19.0-rc6-syzkaller-00418-g972a278fe60c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/07/17 13:02 upstream 972a278fe60c 95cb00d1 .config log report info KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter
* Struck through repros no longer work on HEAD.