syzbot

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BUG: KCSAN: data-race in wait_consider_task / zap_other_threads

read-write to 0xffff88803778d500 of 8 bytes by task 920 on cpu 0:
 task_clear_jobctl_pending kernel/signal.c:344 [inline]
 zap_other_threads+0x90/0x1d0 kernel/signal.c:1356
 do_group_exit+0x140/0x170 kernel/exit.c:915
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:931
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:929
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:929
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88803778d500 of 8 bytes by task 922 on cpu 1:
 task_stopped_code kernel/exit.c:1127 [inline]
 wait_task_stopped kernel/exit.c:1168 [inline]
 wait_consider_task+0x2e1/0x1820 kernel/exit.c:1369
 ptrace_do_wait kernel/exit.c:1409 [inline]
 do_wait+0x224/0x4e0 kernel/exit.c:1470
 kernel_wait4+0x13c/0x1a0 kernel/exit.c:1628
 __do_sys_wait4 kernel/exit.c:1656 [inline]
 __se_sys_wait4 kernel/exit.c:1652 [inline]
 __x64_sys_wait4+0x7a/0x100 kernel/exit.c:1652
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 922 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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