Use ksft_perror() to report error codes from failing ptrace operations to
make it easier to interpret logs when things go wrong.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/fp/sve-ptrace.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c
index b22303778fb0..4cba3bcff660 100644
--- a/tools/testing/selftests/arm64/fp/sve-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c
@@ -95,19 +95,27 @@ static int do_child(void)
 static int get_fpsimd(pid_t pid, struct user_fpsimd_state *fpsimd)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = fpsimd;
 	iov.iov_len = sizeof(*fpsimd);
-	return ptrace(PTRACE_GETREGSET, pid, NT_PRFPREG, &iov);
+	ret = ptrace(PTRACE_GETREGSET, pid, NT_PRFPREG, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_GETREGSET)");
+	return ret;
 }
 
 static int set_fpsimd(pid_t pid, struct user_fpsimd_state *fpsimd)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = fpsimd;
 	iov.iov_len = sizeof(*fpsimd);
-	return ptrace(PTRACE_SETREGSET, pid, NT_PRFPREG, &iov);
+	ret = ptrace(PTRACE_SETREGSET, pid, NT_PRFPREG, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_SETREGSET)");
+	return ret;
 }
 
 static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
@@ -117,6 +125,7 @@ static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
 	void *p;
 	size_t sz = sizeof *sve;
 	struct iovec iov;
+	int ret;
 
 	while (1) {
 		if (*size < sz) {
@@ -132,8 +141,11 @@ static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
 
 		iov.iov_base = *buf;
 		iov.iov_len = sz;
-		if (ptrace(PTRACE_GETREGSET, pid, type->regset, &iov))
+		ret = ptrace(PTRACE_GETREGSET, pid, type->regset, &iov);
+		if (ret) {
+			ksft_perror("ptrace(PTRACE_GETREGSET)");
 			goto error;
+		}
 
 		sve = *buf;
 		if (sve->size <= sz)
@@ -152,10 +164,14 @@ static int set_sve(pid_t pid, const struct vec_type *type,
 		   const struct user_sve_header *sve)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = (void *)sve;
 	iov.iov_len = sve->size;
-	return ptrace(PTRACE_SETREGSET, pid, type->regset, &iov);
+	ret = ptrace(PTRACE_SETREGSET, pid, type->regset, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_SETREGSET)");
+	return ret;
 }
 
 /* Validate setting and getting the inherit flag */

---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250808-arm64-fp-ptrace-perror-210bb7f93c7c

Best regards,
--  
Mark Brown <broonie@kernel.org>

On Tue, 12 Aug 2025 15:37:00 +0100, Mark Brown wrote:
> Use ksft_perror() to report error codes from failing ptrace operations to
> make it easier to interpret logs when things go wrong.
> 
> 

Applied to arm64 (for-next/selftests), thanks!

[1/1] kselftest/arm64: Log error codes in sve-ptrace
      https://git.kernel.org/arm64/c/791d703baddd

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev