syzbot


KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter

Status: closed as invalid on 2020/06/18 14:24
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 933d, last: 810d
similar bugs (4):
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 109d 135d 0/23 auto-closed as invalid on 2022/06/02 15:56
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_enter (3) 10 664d 720d 0/23 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 195d 295d 0/23 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 772d 785d 0/23 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

write to 0xffff88812c02030c of 1 bytes by task 0 on cpu 0:
 tick_nohz_idle_enter+0x8f/0x100 kernel/time/tick-sched.c:1024
 do_idle+0x38/0x290 kernel/sched/idle.c:244
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361
 rest_init+0xe4/0xeb init/main.c:667
 arch_call_rest_init+0x13/0x2b
 start_kernel+0x7fe/0x823 init/main.c:1005
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

read to 0xffff88812c02030c of 1 bytes by task 19062 on cpu 1:
 get_cpu_idle_time_us+0xe5/0x170 kernel/time/tick-sched.c:596
 get_idle_time.isra.0+0x65/0x90 fs/proc/stat.c:53
 show_stat+0x61d/0xa50 fs/proc/stat.c:172
 seq_read+0x2ef/0x940 fs/seq_file.c:206
 pde_read fs/proc/inode.c:292 [inline]
 proc_reg_read+0xb3/0x1b0 fs/proc/inode.c:302
 do_loop_readv_writev fs/read_write.c:715 [inline]
 do_loop_readv_writev fs/read_write.c:702 [inline]
 do_iter_read+0x33f/0x3a0 fs/read_write.c:936
 vfs_readv+0x9c/0xf0 fs/read_write.c:1054
 do_preadv+0x129/0x1c0 fs/read_write.c:1146
 __do_sys_preadv fs/read_write.c:1196 [inline]
 __se_sys_preadv fs/read_write.c:1191 [inline]
 __x64_sys_preadv+0x5e/0x80 fs/read_write.c:1191
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19062 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (10):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2020/05/28 02:07 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 9072c126 .config log report
ci2-upstream-kcsan-gce 2020/05/26 01:57 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 8ca3b7d2 .config log report
ci2-upstream-kcsan-gce 2020/05/02 13:34 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 58da4c35 .config log report
ci2-upstream-kcsan-gce 2020/04/11 11:47 https://github.com/google/ktsan.git kcsan 40959e34d670 a8c6a3f8 .config log report
ci2-upstream-kcsan-gce 2020/03/15 15:15 https://github.com/google/ktsan.git kcsan 941e0d917bbf 749688d2 .config log report
ci2-upstream-kcsan-gce 2020/02/21 10:38 https://github.com/google/ktsan.git kcsan b12d66a6c34f bd2a74a3 .config log report
ci2-upstream-kcsan-gce 2020/02/07 02:52 https://github.com/google/ktsan.git kcsan 245a43005292 06150bf1 .config log report
ci2-upstream-kcsan-gce 2020/02/05 04:59 https://github.com/google/ktsan.git kcsan 245a43005292 93e5e335 .config log report
ci2-upstream-kcsan-gce 2020/02/02 01:04 https://github.com/google/ktsan.git kcsan 245a43005292 2274ad39 .config log report
ci2-upstream-kcsan-gce 2020/01/26 00:44 https://github.com/google/ktsan.git kcsan 245a43005292 f4e7270e .config log report