syzbot

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BUG: KCSAN: data-race in complete_signal / do_group_exit

write to 0xffff88812a8676f4 of 4 bytes by task 11998 on cpu 0:
 complete_signal+0x50b/0x5c0 kernel/signal.c:1044
 __send_signal+0x675/0x8a0 kernel/signal.c:1180
 send_signal+0x211/0x2a0 kernel/signal.c:1241
 do_send_sig_info+0x59/0xc0 kernel/signal.c:1290
 send_sig_info kernel/signal.c:1609 [inline]
 send_sig+0x59/0x80 kernel/signal.c:1619
 pipe_write+0xc3b/0xd40 fs/pipe.c:500
 call_write_iter include/linux/fs.h:1907 [inline]
 new_sync_write+0x303/0x400 fs/read_write.c:484
 __vfs_write+0x9e/0xb0 fs/read_write.c:497
 vfs_write fs/read_write.c:559 [inline]
 vfs_write+0x189/0x380 fs/read_write.c:543
 ksys_write+0x16a/0x1a0 fs/read_write.c:612
 __do_sys_write fs/read_write.c:624 [inline]
 __se_sys_write fs/read_write.c:621 [inline]
 __x64_sys_write+0x49/0x60 fs/read_write.c:621
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812a8676f4 of 4 bytes by task 11985 on cpu 1:
 do_group_exit+0x79/0x1a0 kernel/exit.c:876
 __do_sys_exit_group kernel/exit.c:904 [inline]
 __se_sys_exit_group kernel/exit.c:902 [inline]
 __x64_sys_exit_group+0x2b/0x30 kernel/exit.c:902
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11985 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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