kselftest/arm64: Don't leak pipe fds in pac.exec_sign_all()

[ Upstream commit 27141b690547da5650a420f26ec369ba142a9ebb ]

The PAC exec_sign_all() test spawns some child processes, creating pipes
to be stdin and stdout for the child. It cleans up most of the file
descriptors that are created as part of this but neglects to clean up the
parent end of the child stdin and stdout. Add the missing close() calls.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241111-arm64-pac-test-collisions-v1-1-171875f37e44@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

tools/testing/selftests/arm64/pauth/pac.c

@@ -182,6 +182,9 @@ int exec_sign_all(struct signatures *signed_vals, size_t val)
 		return -1;
 	}
 
+	close(new_stdin[1]);
+	close(new_stdout[0]);
+
 	return 0;
 }