syzbot

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BUG: KCSAN: data-race in do_nanosleep / do_signal_stop

write to 0xffff888100e470ac of 4 bytes by task 4881 on cpu 0:
 freezer_do_not_count include/linux/freezer.h:109 [inline]
 freezable_schedule include/linux/freezer.h:171 [inline]
 do_nanosleep+0xff/0x3d0 kernel/time/hrtimer.c:1896
 hrtimer_nanosleep+0xfa/0x1f0 kernel/time/hrtimer.c:1949
 common_nsleep+0x69/0x80 kernel/time/posix-timers.c:1227
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1267 [inline]
 __se_sys_clock_nanosleep kernel/time/posix-timers.c:1245 [inline]
 __x64_sys_clock_nanosleep+0x1ee/0x220 kernel/time/posix-timers.c:1245
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888100e470ac of 4 bytes by task 4908 on cpu 1:
 task_set_jobctl_pending kernel/signal.c:289 [inline]
 do_signal_stop+0x33e/0x710 kernel/signal.c:2407
 get_signal+0xa16/0x1610 kernel/signal.c:2787
 arch_do_signal_or_restart+0x2a/0x220 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00404040 -> 0x40404040

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4908 Comm: syz-executor.3 Not tainted 5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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