==================================================================
BUG: KCSAN: data-race in complete_signal / do_group_exit

read to 0xffff8880969f3174 of 4 bytes by task 18211 on cpu 1:
 do_group_exit+0x7b/0x1c0 kernel/exit.c:904
 __do_sys_exit_group kernel/exit.c:932 [inline]
 __se_sys_exit_group kernel/exit.c:930 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:930
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880969f3174 of 4 bytes by task 18224 on cpu 0:
 complete_signal+0x530/0x5e0 kernel/signal.c:1039
 __send_signal+0x5ea/0x870 kernel/signal.c:1175
 send_signal+0x224/0x2b0 kernel/signal.c:1236
 do_send_sig_info+0x5f/0xc0 kernel/signal.c:1285
 send_sig_info kernel/signal.c:1604 [inline]
 send_sig+0x5f/0x80 kernel/signal.c:1614
 pipe_write+0x878/0x970 fs/pipe.c:429
 call_write_iter include/linux/fs.h:1895 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18224 Comm: syz-executor.4 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================