2 files changed, 28 insertions, 7 deletions
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index 01f8d3c0cf2c..6922d6417e1c 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -68,7 +68,7 @@
 #define PIDFD_SKIP 3
 #define PIDFD_XFAIL 4
 
-int wait_for_pid(pid_t pid)
+static inline int wait_for_pid(pid_t pid)
 {
 	int status, ret;
 
@@ -78,13 +78,20 @@ again:
 		if (errno == EINTR)
 			goto again;
 
+		ksft_print_msg("waitpid returned -1, errno=%d\n", errno);
 		return -1;
 	}
 
-	if (!WIFEXITED(status))
+	if (!WIFEXITED(status)) {
+		ksft_print_msg(
+		       "waitpid !WIFEXITED, WIFSIGNALED=%d, WTERMSIG=%d\n",
+		       WIFSIGNALED(status), WTERMSIG(status));
 		return -1;
+	}
 
-	return WEXITSTATUS(status);
+	ret = WEXITSTATUS(status);
+	ksft_print_msg("waitpid WEXITSTATUS=%d\n", ret);
+	return ret;
 }
 
 static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
diff --git a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
index 22558524f71c..3fd8e903118f 100644
--- a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
@@ -12,6 +12,7 @@
 #include <string.h>
 #include <syscall.h>
 #include <sys/wait.h>
+#include <sys/mman.h>
 
 #include "pidfd.h"
 #include "../kselftest.h"
@@ -80,7 +81,10 @@ static inline int error_check(struct error *err, const char *test_name)
 	return err->code;
 }
 
+#define CHILD_STACK_SIZE 8192
+
 struct child {
+	char *stack;
 	pid_t pid;
 	int   fd;
 };
@@ -89,17 +93,22 @@ static struct child clone_newns(int (*fn)(void *), void *args,
 				struct error *err)
 {
 	static int flags = CLONE_PIDFD | CLONE_NEWPID | CLONE_NEWNS | SIGCHLD;
-	size_t stack_size = 1024;
-	char *stack[1024] = { 0 };
 	struct child ret;
 
 	if (!(flags & CLONE_NEWUSER) && geteuid() != 0)
 		flags |= CLONE_NEWUSER;
 
+	ret.stack = mmap(NULL, CHILD_STACK_SIZE, PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+	if (ret.stack == MAP_FAILED) {
+		error_set(err, -1, "mmap of stack failed (errno %d)", errno);
+		return ret;
+	}
+
 #ifdef __ia64__
-	ret.pid = __clone2(fn, stack, stack_size, flags, args, &ret.fd);
+	ret.pid = __clone2(fn, ret.stack, CHILD_STACK_SIZE, flags, args, &ret.fd);
 #else
-	ret.pid = clone(fn, stack + stack_size, flags, args, &ret.fd);
+	ret.pid = clone(fn, ret.stack + CHILD_STACK_SIZE, flags, args, &ret.fd);
 #endif
 
 	if (ret.pid < 0) {
@@ -129,6 +138,11 @@ static inline int child_join(struct child *child, struct error *err)
 	else if (r > 0)
 		error_set(err, r, "child %d reported: %d", child->pid, r);
 
+	if (munmap(child->stack, CHILD_STACK_SIZE)) {
+		error_set(err, -1, "munmap of child stack failed (errno %d)", errno);
+		r = -1;
+	}
+
 	return r;
 }