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BUG: KCSAN: data-race in complete_signal / do_group_exit

write to 0xffff88810491e534 of 4 bytes by task 13425 on cpu 0:
 complete_signal+0x541/0x6d0 kernel/signal.c:1053
 __send_signal_locked+0x5cc/0x700 kernel/signal.c:1190
 send_signal_locked+0x28d/0x3a0 kernel/signal.c:1253
 do_send_sig_info+0x9f/0xf0 kernel/signal.c:1296
 send_sig_info kernel/signal.c:1636 [inline]
 send_sig+0x53/0x60 kernel/signal.c:1646
 pipe_write+0x8b1/0xd70 fs/pipe.c:482
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x45a/0x750 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810491e534 of 4 bytes by task 13410 on cpu 1:
 do_group_exit+0x3e/0x150 kernel/exit.c:998
 __do_sys_exit_group kernel/exit.c:1030 [inline]
 __se_sys_exit_group kernel/exit.c:1028 [inline]
 __x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1028
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000002 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13410 Comm: syz-executor.0 Not tainted 6.3.0-rc4-syzkaller-00025-g3a93e40326c8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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