[PATCH] selftests: nci: Fix wrong size of status variables in nci_dev test

[PATCH] selftests: nci: Fix wrong size of status variables in nci_dev test

[Thomas Huth]

From: Thomas Huth <thuth@redhat.com>

pthread_join() stores the thread's return value (a "void *", i.e.
8 bytes on 64 bit computers) into the address of "status", but the
"status" variable is declared as "int" with only 4 bytes. The extra
four bytes clobber whatever is adjacent on the stack, which could
silently corrupt other local variables. Use "intptr_t" to declare
the "status" variables with the correct size.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tools/testing/selftests/nci/nci_dev.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/nci/nci_dev.c b/tools/testing/selftests/nci/nci_dev.c
index 312f84ee0444f..4e7a5856f7ea3 100644
--- a/tools/testing/selftests/nci/nci_dev.c
+++ b/tools/testing/selftests/nci/nci_dev.c
@@ -6,6 +6,7 @@
  * Test code for nci
  */
 
+#include <stdint.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
@@ -404,7 +405,7 @@ FIXTURE_SETUP(NCI)
 	struct msgtemplate msg;
 	pthread_t thread_t;
 	__u32 event_group;
-	int status;
+	intptr_t status;
 	int rc;
 
 	self->open_state = false;
@@ -497,7 +498,7 @@ static void *virtual_deinit_v2(void *data)
 FIXTURE_TEARDOWN(NCI)
 {
 	pthread_t thread_t;
-	int status;
+	intptr_t status;
 	int rc;
 
 	if (self->open_state) {
@@ -585,7 +586,7 @@ int start_polling(int dev_idx, int proto, int virtual_fd, int sd, int fid, int p
 	void *nla_start_poll_data[2] = {&dev_idx, &proto};
 	int nla_start_poll_len[2] = {4, 4};
 	pthread_t thread_t;
-	int status;
+	intptr_t status;
 	int rc;
 
 	rc = pthread_create(&thread_t, NULL, virtual_poll_start,
@@ -605,7 +606,7 @@ int start_polling(int dev_idx, int proto, int virtual_fd, int sd, int fid, int p
 int stop_polling(int dev_idx, int virtual_fd, int sd, int fid, int pid)
 {
 	pthread_t thread_t;
-	int status;
+	intptr_t status;
 	int rc;
 
 	rc = pthread_create(&thread_t, NULL, virtual_poll_stop,
@@ -816,7 +817,7 @@ int disconnect_tag(int nfc_sock, int virtual_fd)
 {
 	pthread_t thread_t;
 	char buf[256];
-	int status;
+	intptr_t status;
 	int len;
 
 	send(nfc_sock, &nci_t4t_select_cmd3[3], sizeof(nci_t4t_select_cmd3) - 3, 0);
@@ -860,7 +861,7 @@ TEST_F(NCI, deinit)
 {
 	struct msgtemplate msg;
 	pthread_t thread_t;
-	int status;
+	intptr_t status;
 	int rc;
 
 	rc = get_nci_devid(self->sd, self->fid, self->pid, self->dev_idex,
-- 
2.55.0

Re: [PATCH] selftests: nci: Fix wrong size of status variables in nci_dev test

[Jakub Kicinski]

On Fri, 10 Jul 2026 13:23:00 +0200 Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> pthread_join() stores the thread's return value (a "void *", i.e.
> 8 bytes on 64 bit computers) into the address of "status", but the
> "status" variable is declared as "int" with only 4 bytes. The extra
> four bytes clobber whatever is adjacent on the stack, which could
> silently corrupt other local variables. Use "intptr_t" to declare
> the "status" variables with the correct size.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

This should go via nfc, I just sent a patch to update MAINTAINERS.

Re: [PATCH] selftests: nci: Fix wrong size of status variables in nci_dev test

[Thomas Huth]

On 10/07/2026 13.23, Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> pthread_join() stores the thread's return value (a "void *", i.e.
> 8 bytes on 64 bit computers) into the address of "status", but the
> "status" variable is declared as "int" with only 4 bytes. The extra
> four bytes clobber whatever is adjacent on the stack, which could
> silently corrupt other local variables. Use "intptr_t" to declare
> the "status" variables with the correct size.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   tools/testing/selftests/nci/nci_dev.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/testing/selftests/nci/nci_dev.c b/tools/testing/selftests/nci/nci_dev.c
> index 312f84ee0444f..4e7a5856f7ea3 100644
> --- a/tools/testing/selftests/nci/nci_dev.c
> +++ b/tools/testing/selftests/nci/nci_dev.c
> @@ -6,6 +6,7 @@
>    * Test code for nci
>    */
>   
> +#include <stdint.h>
>   #include <stdlib.h>
>   #include <errno.h>
>   #include <string.h>
> @@ -404,7 +405,7 @@ FIXTURE_SETUP(NCI)
>   	struct msgtemplate msg;
>   	pthread_t thread_t;
>   	__u32 event_group;
> -	int status;
> +	intptr_t status;
>   	int rc;
>   
>   	self->open_state = false;
> @@ -497,7 +498,7 @@ static void *virtual_deinit_v2(void *data)
>   FIXTURE_TEARDOWN(NCI)
>   {
>   	pthread_t thread_t;
> -	int status;
> +	intptr_t status;
>   	int rc;
>   
>   	if (self->open_state) {
> @@ -585,7 +586,7 @@ int start_polling(int dev_idx, int proto, int virtual_fd, int sd, int fid, int p
>   	void *nla_start_poll_data[2] = {&dev_idx, &proto};
>   	int nla_start_poll_len[2] = {4, 4};
>   	pthread_t thread_t;
> -	int status;
> +	intptr_t status;
>   	int rc;
>   
>   	rc = pthread_create(&thread_t, NULL, virtual_poll_start,
> @@ -605,7 +606,7 @@ int start_polling(int dev_idx, int proto, int virtual_fd, int sd, int fid, int p
>   int stop_polling(int dev_idx, int virtual_fd, int sd, int fid, int pid)
>   {
>   	pthread_t thread_t;
> -	int status;
> +	intptr_t status;
>   	int rc;
>   
>   	rc = pthread_create(&thread_t, NULL, virtual_poll_stop,
> @@ -816,7 +817,7 @@ int disconnect_tag(int nfc_sock, int virtual_fd)
>   {
>   	pthread_t thread_t;
>   	char buf[256];
> -	int status;
> +	intptr_t status;
>   	int len;
>   
>   	send(nfc_sock, &nci_t4t_select_cmd3[3], sizeof(nci_t4t_select_cmd3) - 3, 0);
> @@ -860,7 +861,7 @@ TEST_F(NCI, deinit)
>   {
>   	struct msgtemplate msg;
>   	pthread_t thread_t;
> -	int status;
> +	intptr_t status;
>   	int rc;
>   
>   	rc = get_nci_devid(self->sd, self->fid, self->pid, self->dev_idex,

Friendly ping!

  Thomas

Re: [PATCH] selftests: nci: Fix wrong size of status variables in nci_dev test

[David Heidelberg]

On 13/08/2026 16:45, Thomas Huth wrote:
> On 10/07/2026 13.23, Thomas Huth wrote:
>> From: Thomas Huth <thuth@redhat.com>

[...]

Hello Thomas,

sadly this one missed my inbox for some reason.

Could you please send v2 with added `Fixes: ` and `Cc: stable@vger.kernel.org` tags?

Thanks
David

> 
> Friendly ping!
> 
>   Thomas
> 

-- 
David Heidelberg