syzbot


KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_exit (2)

Status: closed as invalid on 2020/06/18 14:13
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 821d, last: 794d
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_exit (5) 2 248d 275d 0/23 auto-closed as invalid on 2022/01/17 13:05
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_exit (4) 1 664d 664d 0/23 auto-closed as invalid on 2020/11/28 02:26
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_exit (3) 1 717d 717d 0/23 auto-closed as invalid on 2020/10/05 06:48
upstream KCSAN: data-race in get_cpu_idle_time_us / tick_nohz_idle_exit 3 933d 990d 0/23 auto-closed as invalid on 2020/04/07 20:15

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

write to 0xffff88812c12030c of 1 bytes by task 0 on cpu 1:
 tick_nohz_idle_exit+0xbe/0x1d0 kernel/time/tick-sched.c:1191
 do_idle+0xac/0x290 kernel/sched/idle.c:282
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361
 start_secondary+0x169/0x1b0 arch/x86/kernel/smpboot.c:268
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

read to 0xffff88812c12030c of 1 bytes by task 17718 on cpu 0:
 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: 0 PID: 17718 Comm: syz-executor.4 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2020/06/15 12:08 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 8e3ab941 .config log report
ci2-upstream-kcsan-gce 2020/06/05 01:58 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 2420d1bc .config log report
ci2-upstream-kcsan-gce 2020/05/20 14:28 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 4afdfa20 .config log report
ci2-upstream-kcsan-gce 2020/05/19 11:43 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6d882fd2 .config log report