syzbot


KCSAN: data-race in print_cpu / tick_nohz_idle_enter (3)

Status: auto-closed as invalid on 2022/07/29 11:15
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 157d, last: 157d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in print_cpu / tick_nohz_idle_enter (4) 3 109d 118d 0/24 auto-closed as invalid on 2022/09/15 04:11
upstream KCSAN: data-race in print_cpu / tick_nohz_idle_enter 1 431d 431d 0/24 auto-closed as invalid on 2021/10/28 01:37
upstream KCSAN: data-race in print_cpu / tick_nohz_idle_enter (2) 2 362d 386d 0/24 auto-closed as invalid on 2022/01/05 10:03

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

write to 0xffff888237c1e0a8 of 8 bytes by task 0 on cpu 0:
 tick_nohz_start_idle kernel/time/tick-sched.c:673 [inline]
 tick_nohz_idle_enter+0x83/0xc0 kernel/time/tick-sched.c:1161
 do_idle+0x3d/0x250 kernel/sched/idle.c:277
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 rest_init+0xe8/0xf0 init/main.c:726
 start_kernel+0x0/0x656 init/main.c:882
 start_kernel+0x5d1/0x656 init/main.c:1137
 secondary_startup_64_no_verify+0xcf/0xdb

read to 0xffff888237c1e0a8 of 8 bytes by task 14256 on cpu 1:
 print_cpu+0x4ee/0x680 kernel/time/timer_list.c:158
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:291
 traverse+0x150/0x3b0 fs/seq_file.c:111
 seq_read_iter+0x824/0x8e0 fs/seq_file.c:195
 proc_reg_read_iter+0xfa/0x170 fs/proc/inode.c:300
 call_read_iter include/linux/fs.h:2052 [inline]
 generic_file_splice_read+0x1de/0x2c0 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2ac/0x660 fs/splice.c:870
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1262
 __do_sys_sendfile64 fs/read_write.c:1327 [inline]
 __se_sys_sendfile64 fs/read_write.c:1313 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1313
 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+0x46/0xb0

value changed: 0x000000fded2e52a3 -> 0x000000fded2ea622

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14256 Comm: syz-executor.0 Not tainted 5.19.0-rc3-syzkaller-00146-g92f20ff72066-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 2022/06/24 11:05 upstream 92f20ff72066 a5dbd430 .config log report info KCSAN: data-race in print_cpu / tick_nohz_idle_enter
* Struck through repros no longer work on HEAD.