syzbot

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BUG: KCSAN: data-race in check_kill_permission / do_nanosleep

write to 0xffff88813527102c of 4 bytes by task 15012 on cpu 1:
 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+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813527102c of 4 bytes by task 8425 on cpu 0:
 check_kill_permission+0x44/0x2d0 kernel/signal.c:838
 group_send_sig_info kernel/signal.c:1414 [inline]
 kill_pid_info+0x4e/0x100 kernel/signal.c:1452
 kill_proc_info kernel/signal.c:1469 [inline]
 kill_something_info kernel/signal.c:1566 [inline]
 __do_sys_kill kernel/signal.c:3687 [inline]
 __se_sys_kill+0xd3/0x450 kernel/signal.c:3681
 __x64_sys_kill+0x2d/0x40 kernel/signal.c:3681
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8425 Comm: syz-executor.5 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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