[PATCH] selftests/seccomp: report errno and add hints on failure

[PATCH] selftests/seccomp: report errno and add hints on failure

[Sameeksha Sankpal]

Signed-off-by: Sameeksha Sankpal <sameekshasankpal@gmail.com>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 14ba51b52095..d6a85d7b26da 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -4508,7 +4508,11 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
 
 	snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid);
 	ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);
-
+	int rc = get_nth(_metadata, proc_path, 3, &line);
+    	if (rc != 1) {
+        	printf("[ERROR] user_notification_fifo: failed to read stat for PID %d (rc=%d)\n", pid, rc);
+    	}
+    	ASSERT_EQ(rc, 1);
 	status = *line;
 	free(line);
 
@@ -4518,6 +4522,7 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
 TEST(user_notification_fifo)
 {
 	struct seccomp_notif_resp resp = {};
+	ksft_print_msg("[INFO] Starting FIFO notification test\n");
 	struct seccomp_notif req = {};
 	int i, status, listener;
 	pid_t pid, pids[3];
@@ -4535,6 +4540,7 @@ TEST(user_notification_fifo)
 	listener = user_notif_syscall(__NR_getppid,
 				      SECCOMP_FILTER_FLAG_NEW_LISTENER);
 	ASSERT_GE(listener, 0);
+	ksft_print_msg("[INFO] user_notification_fifo: listener PID is %d\n", listener);
 
 	pid = fork();
 	ASSERT_GE(pid, 0);
-- 
2.43.0

Re: [PATCH] selftests/seccomp: report errno and add hints on failure

[Kees Cook]

On Sat, May 17, 2025 at 05:57:40PM +0530, Sameeksha Sankpal wrote:
> Signed-off-by: Sameeksha Sankpal <sameekshasankpal@gmail.com>
> ---
>  tools/testing/selftests/seccomp/seccomp_bpf.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> index 14ba51b52095..d6a85d7b26da 100644
> --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> @@ -4508,7 +4508,11 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
>  
>  	snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid);
>  	ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);
> -
> +	int rc = get_nth(_metadata, proc_path, 3, &line);
> +    	if (rc != 1) {
> +        	printf("[ERROR] user_notification_fifo: failed to read stat for PID %d (rc=%d)\n", pid, rc);
> +    	}
> +    	ASSERT_EQ(rc, 1);

An ASSERT will stop execution, so if it fails, you'll never reach the
printf. And a "printf" shouldn't be used. What you want to use is TH_LOG,
probably like this:


	rc = get_nth(_metadata, proc_path, 3, &line);
  	ASSERT_EQ(rc, 1) {
		TH_LOG("user_notification_fifo: failed to read stat for PID %d (rc=%d)", pid, rc);
	}

And please don't introduce new variables in the middle -- they need to
be declared at the top of the function.

-Kees

-- 
Kees Cook

[PATCH v2] selftests/seccomp: Improve error logging in get_proc_stat()

[Sameeksha Sankpal]

Use TH_LOG to report failure when reading /proc/<pid>/stat in
get_proc_stat(), following kernel test framework conventions.

Previously, printf() was used which is discouraged.

Suggested-by: Kees Cook <kees@kernel.org>

Signed-off-by: Sameeksha Sankpal <sameekshasankpal@gmail.com>
---
v1 -> v2:
- Used TH_LOG instead of printf for error logging
- Moved variable declaration to the top of the function
- Applied review suggestion by Kees Cook

 tools/testing/selftests/seccomp/seccomp_bpf.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index d6a85d7b26da..0f12052ef1c7 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -4505,14 +4505,14 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
 	char proc_path[100] = {0};
 	char status;
 	char *line;
+	int rc;
 
 	snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid);
 	ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);
-	int rc = get_nth(_metadata, proc_path, 3, &line);
-    	if (rc != 1) {
-        	printf("[ERROR] user_notification_fifo: failed to read stat for PID %d (rc=%d)\n", pid, rc);
-    	}
-    	ASSERT_EQ(rc, 1);
+	rc = get_nth(_metadata, proc_path, 3, &line);
+    ASSERT_EQ(rc, 1) {
+		TH_LOG("user_notification_fifo: failed to read stat for PID %d (rc=%d)", pid, rc);
+	}
 	status = *line;
 	free(line);
 
-- 
2.43.0

Re: [PATCH v2] selftests/seccomp: Improve error logging in get_proc_stat()

[Kees Cook]

On Wed, May 28, 2025 at 06:38:39AM +0530, Sameeksha Sankpal wrote:
> Use TH_LOG to report failure when reading /proc/<pid>/stat in
> get_proc_stat(), following kernel test framework conventions.
> 
> Previously, printf() was used which is discouraged.

printf wasn't used previous, that was in your v1. :)

> 
> Suggested-by: Kees Cook <kees@kernel.org>
> 

No blank line here -- other tags should all be together with the S-o-b
line.

> Signed-off-by: Sameeksha Sankpal <sameekshasankpal@gmail.com>
> ---
> v1 -> v2:
> - Used TH_LOG instead of printf for error logging
> - Moved variable declaration to the top of the function
> - Applied review suggestion by Kees Cook
> 
>  tools/testing/selftests/seccomp/seccomp_bpf.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> index d6a85d7b26da..0f12052ef1c7 100644
> --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> @@ -4505,14 +4505,14 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
>  	char proc_path[100] = {0};
>  	char status;
>  	char *line;
> +	int rc;
>  
>  	snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid);
>  	ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);
> -	int rc = get_nth(_metadata, proc_path, 3, &line);
> -    	if (rc != 1) {
> -        	printf("[ERROR] user_notification_fifo: failed to read stat for PID %d (rc=%d)\n", pid, rc);
> -    	}
> -    	ASSERT_EQ(rc, 1);

This patch is against your v1 patch -- it doesn't apply to the seccomp
tree as-is. Please rebase your v2 off of the upstream tree rather than
your v1.

> +	rc = get_nth(_metadata, proc_path, 3, &line);
> +    ASSERT_EQ(rc, 1) {

Indenting looks wrong here, double-check you're using tabs. (And please
use scripts/checkpatch.pl to check your patch for common errors.)

> +		TH_LOG("user_notification_fifo: failed to read stat for PID %d (rc=%d)", pid, rc);
> +	}
>  	status = *line;
>  	free(line);

Code-wise, it looks good. Please respin for a v3 and this change should
be good to land.

-Kees

-- 
Kees Cook

[PATCH v3] selftests/seccomp: Fix indentation and rebase error logging patch

[Sameeksha Sankpal]

Rebase the error logging enhancement for get_proc_stat() against the upstream seccomp tree with proper indentation formatting.

Suggested-by: Kees Cook <kees@kernel.org>
Signed-off-by: Sameeksha Sankpal <sameekshasankpal@gmail.com>
---
v1 -> v2:
- Used TH_LOG instead of printf for error logging  
- Moved variable declaration to the top of the function
- Applied review suggestion by Kees Cook

v2 -> v3:
- Rebased against upstream seccomp tree (was previously against v1)
- Fixed indentation to use tabs instead of spaces
- Used scripts/checkpatch.pl to check the patch for common errors
- Removed the blank line beforeS S-o-b added in v2

 tools/testing/selftests/seccomp/seccomp_bpf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 61acbd45ffaa..dbd7e705a2af 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -4508,9 +4508,14 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid)
 	char proc_path[100] = {0};
 	char status;
 	char *line;
+	int rc;
 
 	snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid);
 	ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);
+	rc = get_nth(_metadata, proc_path, 3, &line);
+	ASSERT_EQ(rc, 1) {
+		TH_LOG("user_notification_fifo: failed to read stat for PID %d (rc=%d)", pid, rc);
+	}
 
 	status = *line;
 	free(line);
-- 
2.43.0