syzbot


KCSAN: data-race in timerfd_clock_was_set / timerfd_release (2)

Status: auto-closed as invalid on 2021/11/07 23:22
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 427d, last: 427d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in timerfd_clock_was_set / timerfd_release 2 525d 537d 0/24 auto-closed as invalid on 2021/08/02 04:06

Sample crash report:
==================================================================
BUG: KCSAN: data-race in timerfd_clock_was_set / timerfd_release

write to 0xffff88810981ffd4 of 1 bytes by task 1014 on cpu 0:
 __timerfd_remove_cancel fs/timerfd.c:137 [inline]
 timerfd_remove_cancel fs/timerfd.c:147 [inline]
 timerfd_release+0x5d/0x1c0 fs/timerfd.c:239
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810981ffd4 of 1 bytes by task 13039 on cpu 1:
 timerfd_clock_was_set+0x49/0x140 fs/timerfd.c:105
 clock_was_set+0x429/0x460 kernel/time/hrtimer.c:980
 timekeeping_inject_offset+0x6cc/0x700 kernel/time/timekeeping.c:1375
 do_adjtimex+0x5b5/0x6a0 kernel/time/timekeeping.c:2409
 posix_clock_realtime_adj+0x11/0x20 kernel/time/posix-timers.c:191
 do_clock_adjtime kernel/time/posix-timers.c:1109 [inline]
 __do_sys_clock_adjtime kernel/time/posix-timers.c:1121 [inline]
 __se_sys_clock_adjtime kernel/time/posix-timers.c:1112 [inline]
 __x64_sys_clock_adjtime+0x13e/0x1d0 kernel/time/posix-timers.c:1112
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 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: 13039 Comm: syz-executor.0 Not tainted 5.15.0-rc3-syzkaller #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 2021/10/03 23:17 upstream 6761a0ae9895 db0f5787 .config log report info KCSAN: data-race in timerfd_clock_was_set / timerfd_release
* Struck through repros no longer work on HEAD.