[PATCH 0/3] examples: format truncation bugs

[PATCH 0/3] examples: format truncation bugs

[Stephen Hemminger]

Enable format-overflow warnings in examples and fix the bugs.

Stephen Hemminger (3):
  examples/server_node_efd: fix format overflow
  examples/vdpa: fix format overflow warning
  examples: re-enable format truncation warning

 examples/meson.build                       |  5 ++---
 examples/server_node_efd/efd_server/main.c |  2 +-
 examples/vdpa/main.c                       | 12 ++++++------
 3 files changed, 9 insertions(+), 10 deletions(-)

-- 
2.51.0

[PATCH 1/3] examples/server_node_efd: fix format overflow

[Stephen Hemminger]

If format-truncation is enabled, the compiler detects a string overflow
since the snprintf() is putting ethernet address and new line
in buffer only sized for the address.

Fixes: 39aad0e88c58 ("examples/flow_distributor: new example to demonstrate EFD")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/server_node_efd/efd_server/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/server_node_efd/efd_server/main.c b/examples/server_node_efd/efd_server/main.c
index 75ff0ea532..62c3f4a16d 100644
--- a/examples/server_node_efd/efd_server/main.c
+++ b/examples/server_node_efd/efd_server/main.c
@@ -68,7 +68,7 @@ static const char *
 get_printable_mac_addr(uint16_t port)
 {
 	static const char err_address[] = "00:00:00:00:00:00";
-	static char addresses[RTE_MAX_ETHPORTS][sizeof(err_address)];
+	static char addresses[RTE_MAX_ETHPORTS][RTE_ETHER_ADDR_FMT_SIZE + 1];
 	struct rte_ether_addr mac;
 	int ret;
 
-- 
2.51.0

[PATCH 2/3] examples/vdpa: fix format overflow warning

[Stephen Hemminger]

The ifname is limited to 128 characters, but it would allow up
to 128 characters as prefix then could overflow creating ifname.

Change to limit path prefix to 124 (128 - sizeof("1024"))
to avoid possible format overflow

Fixes: 38f8ab0bbc8d ("vhost: make vDPA framework bus agnostic")
Cc: maxime.coquelin@redhat.com
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/vdpa/main.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
index 289db26498..bdf751ad63 100644
--- a/examples/vdpa/main.c
+++ b/examples/vdpa/main.c
@@ -22,6 +22,8 @@
 
 #define MAX_PATH_LEN 128
 #define MAX_VDPA_SAMPLE_PORTS 1024
+#define stringify(x) (#x)
+#define MAX_VDPA_STR_LEN sizeof(stringify(MAX_VDPA_SAMPLE_PORTS))
 #define RTE_LOGTYPE_VDPA RTE_LOGTYPE_USER1
 
 struct vdpa_port {
@@ -36,7 +38,7 @@ struct vdpa_port {
 
 static struct vdpa_port vports[MAX_VDPA_SAMPLE_PORTS];
 
-static char iface[MAX_PATH_LEN];
+static char iface[MAX_PATH_LEN - MAX_VDPA_STR_LEN];
 static int devcnt;
 static int interactive;
 static int client_mode;
@@ -74,9 +76,8 @@ parse_args(int argc, char **argv)
 			break;
 		/* long options */
 		case 0:
-			if (strncmp(long_option[idx].name, "iface",
-						MAX_PATH_LEN) == 0) {
-				rte_strscpy(iface, optarg, MAX_PATH_LEN);
+			if (!strcmp(long_option[idx].name, "iface")) {
+				rte_strscpy(iface, optarg, sizeof(iface));
 				printf("iface %s\n", iface);
 			}
 			if (!strcmp(long_option[idx].name, "interactive")) {
-- 
2.51.0

[PATCH 3/3] examples: re-enable format truncation warning

[Stephen Hemminger]

There were several hidden bugs in examples because format
truncation warning was disabled.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/meson.build | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/examples/meson.build b/examples/meson.build
index 8e8968a1fa..25d9c88457 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -78,10 +78,9 @@ else
     examples = get_option('examples').split(',')
     allow_skips = false # error out if we can't build a requested app
 endif
+
 default_cflags = machine_args
-if cc.has_argument('-Wno-format-truncation')
-    default_cflags += '-Wno-format-truncation'
-endif
+
 default_ldflags = dpdk_extra_ldflags
 if get_option('default_library') == 'static' and not is_windows
     default_ldflags += ['-Wl,--export-dynamic']
-- 
2.51.0

[PATCH v2 0/7] fix format-truncation warnings

[Stephen Hemminger]

Enable and fix format-truncation warnings in examples and tests.

v2 - fix build warnings (more fixes needed)
   - do test as well (could be separate series?)

Stephen Hemminger (7):
  examples/server_node_efd: fix format overflow
  examples/vdpa: fix format overflow warning
  examples/ip_reassembly: add check before formatting name
  examples: re-enable format truncation warning
  test: refactor file prefix arg handling
  test: increase size of memzone name
  test: re-enable format-truncation warnings

 app/test/meson.build                       |   1 -
 app/test/test_eal_flags.c                  | 161 ++++++++-------------
 app/test/test_memzone.c                    |   2 +-
 examples/ip_reassembly/main.c              |   7 +
 examples/meson.build                       |   5 +-
 examples/server_node_efd/efd_server/main.c |   2 +-
 examples/server_node_efd/shared/common.h   |   3 +-
 examples/vdpa/main.c                       |   9 +-
 8 files changed, 77 insertions(+), 113 deletions(-)

-- 
2.51.0

[PATCH v2 1/7] examples/server_node_efd: fix format overflow

[Stephen Hemminger]

If format-truncation is enabled, the compiler detects a string overflow
since the snprintf() is putting ethernet address and new line
in buffer only sized for the address.

Since get_rx_queue_name() is used to create a ring name.
The buffer should be sized to be a valid ring name.
This fixes some format-overflow warnings and also corrects
for future errors.

Fixes: 39aad0e88c58 ("examples/flow_distributor: new example to demonstrate EFD")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/server_node_efd/efd_server/main.c | 2 +-
 examples/server_node_efd/shared/common.h   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/examples/server_node_efd/efd_server/main.c b/examples/server_node_efd/efd_server/main.c
index 75ff0ea532..62c3f4a16d 100644
--- a/examples/server_node_efd/efd_server/main.c
+++ b/examples/server_node_efd/efd_server/main.c
@@ -68,7 +68,7 @@ static const char *
 get_printable_mac_addr(uint16_t port)
 {
 	static const char err_address[] = "00:00:00:00:00:00";
-	static char addresses[RTE_MAX_ETHPORTS][sizeof(err_address)];
+	static char addresses[RTE_MAX_ETHPORTS][RTE_ETHER_ADDR_FMT_SIZE + 1];
 	struct rte_ether_addr mac;
 	int ret;
 
diff --git a/examples/server_node_efd/shared/common.h b/examples/server_node_efd/shared/common.h
index e1ab7e62b7..6726e2031e 100644
--- a/examples/server_node_efd/shared/common.h
+++ b/examples/server_node_efd/shared/common.h
@@ -58,8 +58,9 @@ get_rx_queue_name(unsigned int id)
 	/*
 	 * Buffer for return value. Size calculated by %u being replaced
 	 * by maximum 3 digits (plus an extra byte for safety)
+	 * Used as ring name, so upper limit is ring name size.
 	 */
-	static char buffer[sizeof(MP_NODE_RXQ_NAME) + 2];
+	static char buffer[RTE_RING_NAMESIZE];
 
 	snprintf(buffer, sizeof(buffer), MP_NODE_RXQ_NAME, id);
 	return buffer;
-- 
2.51.0

[PATCH v2 2/7] examples/vdpa: fix format overflow warning

[Stephen Hemminger]

The ifname is limited to 128 characters, but it would allow up
to 128 characters as prefix then could overflow creating ifname.

Change to limit path prefix to 124 (128 - sizeof("1024"))
to avoid possible format overflow

Fixes: 38f8ab0bbc8d ("vhost: make vDPA framework bus agnostic")
Cc: maxime.coquelin@redhat.com
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/vdpa/main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
index 289db26498..7fd0e55b20 100644
--- a/examples/vdpa/main.c
+++ b/examples/vdpa/main.c
@@ -22,6 +22,8 @@
 
 #define MAX_PATH_LEN 128
 #define MAX_VDPA_SAMPLE_PORTS 1024
+#define stringify(x) (#x)
+#define MAX_VDPA_STR_LEN sizeof(stringify(MAX_VDPA_SAMPLE_PORTS))
 #define RTE_LOGTYPE_VDPA RTE_LOGTYPE_USER1
 
 struct vdpa_port {
@@ -36,7 +38,7 @@ struct vdpa_port {
 
 static struct vdpa_port vports[MAX_VDPA_SAMPLE_PORTS];
 
-static char iface[MAX_PATH_LEN];
+static char iface[MAX_PATH_LEN - MAX_VDPA_STR_LEN];
 static int devcnt;
 static int interactive;
 static int client_mode;
@@ -74,9 +76,8 @@ parse_args(int argc, char **argv)
 			break;
 		/* long options */
 		case 0:
-			if (strncmp(long_option[idx].name, "iface",
-						MAX_PATH_LEN) == 0) {
-				rte_strscpy(iface, optarg, MAX_PATH_LEN);
+			if (!strcmp(long_option[idx].name, "iface")) {
+				rte_strscpy(iface, optarg, sizeof(iface));
 				printf("iface %s\n", iface);
 			}
 			if (!strcmp(long_option[idx].name, "interactive")) {
-- 
2.51.0

Re: [PATCH v2 2/7] examples/vdpa: fix format overflow warning

[Bruce Richardson]

On Tue, Nov 11, 2025 at 02:17:19PM -0800, Stephen Hemminger wrote:
> The ifname is limited to 128 characters, but it would allow up
> to 128 characters as prefix then could overflow creating ifname.
> 
> Change to limit path prefix to 124 (128 - sizeof("1024"))

nit: sizeof("1024") == 5, because of the \0.

> to avoid possible format overflow
> 
> Fixes: 38f8ab0bbc8d ("vhost: make vDPA framework bus agnostic")
> Cc: maxime.coquelin@redhat.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

I assume this was found by enabling compiler warnings. It would be good to
include the actual warning message in the commit log, given that the patch
doesn't actually modify the line at which the overflow occurs.

Acked-by: Bruce Richardson <bruce.richardson@intel.com>


> ---
>  examples/vdpa/main.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
> index 289db26498..7fd0e55b20 100644
> --- a/examples/vdpa/main.c
> +++ b/examples/vdpa/main.c
> @@ -22,6 +22,8 @@
>  
>  #define MAX_PATH_LEN 128
>  #define MAX_VDPA_SAMPLE_PORTS 1024
> +#define stringify(x) (#x)
> +#define MAX_VDPA_STR_LEN sizeof(stringify(MAX_VDPA_SAMPLE_PORTS))

We have RTE_STR() and _RTE_STR() in rte_common.h

>  #define RTE_LOGTYPE_VDPA RTE_LOGTYPE_USER1
>  
>  struct vdpa_port {
> @@ -36,7 +38,7 @@ struct vdpa_port {
>  
>  static struct vdpa_port vports[MAX_VDPA_SAMPLE_PORTS];
>  
> -static char iface[MAX_PATH_LEN];
> +static char iface[MAX_PATH_LEN - MAX_VDPA_STR_LEN];
>  static int devcnt;
>  static int interactive;
>  static int client_mode;
> @@ -74,9 +76,8 @@ parse_args(int argc, char **argv)
>  			break;
>  		/* long options */
>  		case 0:
> -			if (strncmp(long_option[idx].name, "iface",
> -						MAX_PATH_LEN) == 0) {
> -				rte_strscpy(iface, optarg, MAX_PATH_LEN);
> +			if (!strcmp(long_option[idx].name, "iface")) {
> +				rte_strscpy(iface, optarg, sizeof(iface));

I realise that the rte_strscpy function is what was here before, but given
that we are not checking the return value, there is no reason to choose the
dpdk-only strscpy function over the more-standard strlcpy.

>  				printf("iface %s\n", iface);
>  			}
>  			if (!strcmp(long_option[idx].name, "interactive")) {
> -- 
> 2.51.0
> 

[PATCH v2 3/7] examples/ip_reassembly: add check before formatting name

[Stephen Hemminger]

In theory, lcore and queue could be so large that mbuf pool name
could overflow. But that can never happen since lcore and queue
will be in range. Add a check so that static tools know that.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/ip_reassembly/main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
index 17ae76d4ba..25b904dbd4 100644
--- a/examples/ip_reassembly/main.c
+++ b/examples/ip_reassembly/main.c
@@ -884,6 +884,13 @@ setup_queue_tbl(struct rx_queue *rxq, uint32_t lcore, uint32_t queue)
 
 	nb_mbuf = RTE_MAX(nb_mbuf, (uint32_t)NB_MBUF);
 
+	/* Should never happen but check so that pool name won't be too long. */
+	if (lcore > RTE_MAX_LCORE || queue > RTE_MAX_QUEUES_PER_PORT) {
+		RTE_LOG(ERR, IP_RSMBL, "invalid lcore %u or queue %u",
+			lcore, queue);
+		return -1;
+	}
+
 	snprintf(buf, sizeof(buf), "mbuf_pool_%u_%u", lcore, queue);
 
 	rxq->pool = rte_pktmbuf_pool_create(buf, nb_mbuf, MEMPOOL_CACHE_SIZE, 0,
-- 
2.51.0

RE: [PATCH v2 3/7] examples/ip_reassembly: add check before formatting name

[Konstantin Ananyev]

> 
> In theory, lcore and queue could be so large that mbuf pool name
> could overflow. But that can never happen since lcore and queue
> will be in range. Add a check so that static tools know that.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
>  examples/ip_reassembly/main.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
> index 17ae76d4ba..25b904dbd4 100644
> --- a/examples/ip_reassembly/main.c
> +++ b/examples/ip_reassembly/main.c
> @@ -884,6 +884,13 @@ setup_queue_tbl(struct rx_queue *rxq, uint32_t lcore,
> uint32_t queue)
> 
>  	nb_mbuf = RTE_MAX(nb_mbuf, (uint32_t)NB_MBUF);
> 
> +	/* Should never happen but check so that pool name won't be too long. */
> +	if (lcore > RTE_MAX_LCORE || queue > RTE_MAX_QUEUES_PER_PORT) {
> +		RTE_LOG(ERR, IP_RSMBL, "invalid lcore %u or queue %u",
> +			lcore, queue);
> +		return -1;
> +	}
> +
>  	snprintf(buf, sizeof(buf), "mbuf_pool_%u_%u", lcore, queue);
> 
>  	rxq->pool = rte_pktmbuf_pool_create(buf, nb_mbuf,
> MEMPOOL_CACHE_SIZE, 0,
> --
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
> 2.51.0

Re: [PATCH v2 3/7] examples/ip_reassembly: add check before formatting name

[Bruce Richardson]

On Tue, Nov 11, 2025 at 02:17:20PM -0800, Stephen Hemminger wrote:
> In theory, lcore and queue could be so large that mbuf pool name
> could overflow. But that can never happen since lcore and queue
> will be in range. Add a check so that static tools know that.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---

Again, maybe include the warning omitted by the compiler

Acked-by: Bruce Richardson <bruce.richardson@intel.com>


>  examples/ip_reassembly/main.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
> index 17ae76d4ba..25b904dbd4 100644
> --- a/examples/ip_reassembly/main.c
> +++ b/examples/ip_reassembly/main.c
> @@ -884,6 +884,13 @@ setup_queue_tbl(struct rx_queue *rxq, uint32_t lcore, uint32_t queue)
>  
>  	nb_mbuf = RTE_MAX(nb_mbuf, (uint32_t)NB_MBUF);
>  
> +	/* Should never happen but check so that pool name won't be too long. */
> +	if (lcore > RTE_MAX_LCORE || queue > RTE_MAX_QUEUES_PER_PORT) {
> +		RTE_LOG(ERR, IP_RSMBL, "invalid lcore %u or queue %u",
> +			lcore, queue);
> +		return -1;
> +	}
> +
>  	snprintf(buf, sizeof(buf), "mbuf_pool_%u_%u", lcore, queue);
>  
>  	rxq->pool = rte_pktmbuf_pool_create(buf, nb_mbuf, MEMPOOL_CACHE_SIZE, 0,
> -- 
> 2.51.0
> 

[PATCH v2 4/7] examples: re-enable format truncation warning

[Stephen Hemminger]

There were several hidden bugs in examples because format
truncation warning was disabled.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/meson.build | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/examples/meson.build b/examples/meson.build
index 8e8968a1fa..25d9c88457 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -78,10 +78,9 @@ else
     examples = get_option('examples').split(',')
     allow_skips = false # error out if we can't build a requested app
 endif
+
 default_cflags = machine_args
-if cc.has_argument('-Wno-format-truncation')
-    default_cflags += '-Wno-format-truncation'
-endif
+
 default_ldflags = dpdk_extra_ldflags
 if get_option('default_library') == 'static' and not is_windows
     default_ldflags += ['-Wl,--export-dynamic']
-- 
2.51.0

Re: [PATCH v2 4/7] examples: re-enable format truncation warning

[Bruce Richardson]

On Tue, Nov 11, 2025 at 02:17:21PM -0800, Stephen Hemminger wrote:
> There were several hidden bugs in examples because format
> truncation warning was disabled.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

>  examples/meson.build | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/examples/meson.build b/examples/meson.build
> index 8e8968a1fa..25d9c88457 100644
> --- a/examples/meson.build
> +++ b/examples/meson.build
> @@ -78,10 +78,9 @@ else
>      examples = get_option('examples').split(',')
>      allow_skips = false # error out if we can't build a requested app
>  endif
> +
>  default_cflags = machine_args
> -if cc.has_argument('-Wno-format-truncation')
> -    default_cflags += '-Wno-format-truncation'
> -endif
> +
>  default_ldflags = dpdk_extra_ldflags
>  if get_option('default_library') == 'static' and not is_windows
>      default_ldflags += ['-Wl,--export-dynamic']
> -- 
> 2.51.0
> 

[PATCH v2 5/7] test: refactor file prefix arg handling

[Stephen Hemminger]

Make setting up --file-prefix arg logic into a function,
and avoid impossible case of file prefix path causing overflow
of string.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/test_eal_flags.c | 161 ++++++++++++++------------------------
 1 file changed, 59 insertions(+), 102 deletions(-)

diff --git a/app/test/test_eal_flags.c b/app/test/test_eal_flags.c
index e32f83d3c8..05b4135a51 100644
--- a/app/test/test_eal_flags.c
+++ b/app/test/test_eal_flags.c
@@ -121,6 +121,8 @@ test_misc_flags(void)
 #define no_shconf "--no-shconf"
 #define allow "--allow"
 #define vdev "--vdev"
+#define file_prefix "--file-prefix"
+
 #define memtest "memtest"
 #define memtest1 "memtest1"
 #define memtest2 "memtest2"
@@ -312,26 +314,40 @@ get_number_of_sockets(void)
 }
 #endif
 
-/*
- * Test that the app doesn't run with invalid allow option.
- * Final tests ensures it does run with valid options as sanity check (one
- * test for with Domain+BDF, second for just with BDF)
- */
+/* Get the file_prefix xommand line argument */
 static int
-test_allow_flag(void)
+get_file_prefix(char *prefix, size_t size)
 {
-	unsigned i;
 #ifdef RTE_EXEC_ENV_FREEBSD
 	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
+	RTE_SET_USED(len);
+	*prefix = 0;
+	return 0;
 #else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
+	char tmp[PATH_MAX];
+
 	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
 		printf("Error - unable to get current prefix!\n");
 		return -1;
 	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
+	snprintf(prefix, size, "%s=%s", file_prefix, tmp);
+	return 0;
 #endif
+}
+
+/*
+ * Test that the app doesn't run with invalid allow option.
+ * Final tests ensures it does run with valid options as sanity check (one
+ * test for with Domain+BDF, second for just with BDF)
+ */
+static int
+test_allow_flag(void)
+{
+	unsigned i;
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	const char *wlinval[][7] = {
 		{prgname, prefix, mp_flag,
@@ -387,17 +403,10 @@ test_allow_flag(void)
 static int
 test_invalid_b_flag(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	const char *blinval[][5] = {
 		{prgname, prefix, mp_flag, "-b", "error"},
@@ -491,17 +500,10 @@ test_invalid_vdev_flag(void)
 static int
 test_invalid_r_flag(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	const char *rinval[][5] = {
 			{prgname, prefix, mp_flag, "-r", "error"},
@@ -535,17 +537,10 @@ test_invalid_r_flag(void)
 static int
 test_missing_c_flag(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/* -c flag but no coremask value */
 	const char *argv1[] = { prgname, prefix, mp_flag, "-c"};
@@ -694,17 +689,10 @@ test_missing_c_flag(void)
 static int
 test_main_lcore_flag(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char *prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	if (!rte_lcore_is_enabled(0) || !rte_lcore_is_enabled(1))
 		return TEST_SKIPPED;
@@ -751,17 +739,10 @@ test_main_lcore_flag(void)
 static int
 test_invalid_n_flag(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/* -n flag but no value */
 	const char *argv1[] = { prgname, prefix, no_huge, no_shconf,
@@ -803,18 +784,10 @@ test_invalid_n_flag(void)
 static int
 test_no_hpet_flag(void)
 {
-	char prefix[PATH_MAX] = "";
+	char prefix[PATH_MAX + sizeof(file_prefix)];
 
-#ifdef RTE_EXEC_ENV_FREEBSD
-	return 0;
-#else
-	char tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/* With --no-hpet */
 	const char *argv1[] = {prgname, prefix, mp_flag, no_hpet};
@@ -913,17 +886,14 @@ test_misc_flags(void)
 	const char * prefix = "";
 	const char * nosh_prefix = "";
 #else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
+	char prefix[PATH_MAX + sizeof(file_prefix)];
 	const char * nosh_prefix = "--file-prefix=noshconf";
 	FILE * hugedir_handle = NULL;
 	char line[PATH_MAX] = {0};
 	unsigned i, isempty = 1;
 
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/*
 	 * get first valid hugepage path
@@ -1239,16 +1209,10 @@ test_file_prefix(void)
 	 *    run in legacy mode, and not present at all after run in default
 	 *    mem mode
 	 */
-	char prefix[PATH_MAX] = "";
+	char prefix[PATH_MAX + sizeof(file_prefix)];
 
-#ifdef RTE_EXEC_ENV_FREEBSD
-	return 0;
-#else
-	if (get_current_prefix(prefix, sizeof(prefix)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-#endif
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/* this should fail unless the test itself is run with "memtest" prefix */
 	const char *argv0[] = {prgname, mp_flag, "-m",
@@ -1525,17 +1489,10 @@ populate_socket_mem_param(int num_sockets, const char *mem,
 static int
 test_memory_flags(void)
 {
-#ifdef RTE_EXEC_ENV_FREEBSD
-	/* BSD target doesn't support prefixes at this point */
-	const char * prefix = "";
-#else
-	char prefix[PATH_MAX], tmp[PATH_MAX];
-	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
-		printf("Error - unable to get current prefix!\n");
-		return -1;
-	}
-	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
-#endif
+	char prefix[PATH_MAX + sizeof(file_prefix)];
+
+	if (get_file_prefix(prefix, sizeof(prefix)) != 0)
+		return TEST_FAILED;
 
 	/* valid -m flag and mp flag */
 	const char *argv0[] = {prgname, prefix, mp_flag,
-- 
2.51.0

[PATCH v2 6/7] test: increase size of memzone name

[Stephen Hemminger]

The tests were using a name buffer of 20 characters which could
overflow if number of memory zones got large. The upper limit
is defined as RTE_MEMZONE_NAMESIZE so use that.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/test_memzone.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/test/test_memzone.c b/app/test/test_memzone.c
index 506725ea41..6586dad18d 100644
--- a/app/test/test_memzone.c
+++ b/app/test/test_memzone.c
@@ -872,7 +872,7 @@ test_memzone_free(void)
 {
 	const struct rte_memzone **mz;
 	int i;
-	char name[20];
+	char name[RTE_MEMZONE_NAMESIZE];
 	int rc = -1;
 
 	mz = rte_calloc("memzone_test", rte_memzone_max_get() + 1,
-- 
2.51.0

Re: [PATCH v2 6/7] test: increase size of memzone name

[Bruce Richardson]

On Tue, Nov 11, 2025 at 02:17:23PM -0800, Stephen Hemminger wrote:
> The tests were using a name buffer of 20 characters which could
> overflow if number of memory zones got large. The upper limit
> is defined as RTE_MEMZONE_NAMESIZE so use that.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

> ---
>  app/test/test_memzone.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/app/test/test_memzone.c b/app/test/test_memzone.c
> index 506725ea41..6586dad18d 100644
> --- a/app/test/test_memzone.c
> +++ b/app/test/test_memzone.c
> @@ -872,7 +872,7 @@ test_memzone_free(void)
>  {
>  	const struct rte_memzone **mz;
>  	int i;
> -	char name[20];
> +	char name[RTE_MEMZONE_NAMESIZE];
>  	int rc = -1;
>  
>  	mz = rte_calloc("memzone_test", rte_memzone_max_get() + 1,
> -- 
> 2.51.0
> 

[PATCH v2 7/7] test: re-enable format-truncation warnings

[Stephen Hemminger]

Tests should be built with warnings.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/meson.build | 1 -
 1 file changed, 1 deletion(-)

diff --git a/app/test/meson.build b/app/test/meson.build
index 8df8d3edd1..66cbabe9fe 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -260,7 +260,6 @@ cflags += no_wvla_cflag
 extra_flags = [
         # Strict-aliasing rules are violated by uint8_t[] to context size casts.
         '-fno-strict-aliasing',
-        '-Wno-format-truncation',
 ]
 
 foreach arg: extra_flags
-- 
2.51.0

Re: [PATCH v2 7/7] test: re-enable format-truncation warnings

[Bruce Richardson]

On Tue, Nov 11, 2025 at 02:17:24PM -0800, Stephen Hemminger wrote:
> Tests should be built with warnings.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

>  app/test/meson.build | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/app/test/meson.build b/app/test/meson.build
> index 8df8d3edd1..66cbabe9fe 100644
> --- a/app/test/meson.build
> +++ b/app/test/meson.build
> @@ -260,7 +260,6 @@ cflags += no_wvla_cflag
>  extra_flags = [
>          # Strict-aliasing rules are violated by uint8_t[] to context size casts.
>          '-fno-strict-aliasing',
> -        '-Wno-format-truncation',
>  ]
>  
>  foreach arg: extra_flags
> -- 
> 2.51.0
> 

[PATCH v3 0/4] examples: fix format-truncation warnings

[Stephen Hemminger]

Enable and fix format-truncation warnings in examples

v3 - examples only, update commit messages

Stephen Hemminger (4):
  examples/server_node_efd: fix format overflow
  examples/vdpa: fix format overflow warning
  examples/ip_reassembly: add check before formatting name
  examples: enable format truncation warning

 examples/ip_reassembly/main.c              | 7 +++++++
 examples/meson.build                       | 5 ++---
 examples/server_node_efd/efd_server/main.c | 2 +-
 examples/server_node_efd/shared/common.h   | 3 ++-
 examples/vdpa/main.c                       | 9 +++++----
 5 files changed, 17 insertions(+), 9 deletions(-)

-- 
2.51.0

[PATCH v3 1/4] examples/server_node_efd: fix format overflow

[Stephen Hemminger]

If format-truncation is enabled, the compiler detects a string overflow
since the snprintf() is putting ethernet address and new line
in buffer only sized for the address.

Since get_rx_queue_name() is used to create a ring name.
The buffer should be sized to be a valid ring name.
This fixes some format-overflow warnings and also corrects
for future errors.

In file included from ../examples/server_node_efd/efd_server/main.c:31:
In function ‘get_printable_mac_addr’,
    inlined from ‘do_stats_display’ at ../examples/server_node_efd/efd_server/main.c:136:3:
../lib/net/rte_ether.h:248:36: warning: ‘snprintf’ output truncated before the last format character [-Wformat-truncation=]
  248 | #define RTE_ETHER_ADDR_PRT_FMT     "%02X:%02X:%02X:%02X:%02X:%02X"
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../examples/server_node_efd/efd_server/main.c:86:33: note: in expansion of macro ‘RTE_ETHER_ADDR_PRT_FMT’
   86 |                                 RTE_ETHER_ADDR_PRT_FMT "\n",
      |                                 ^~~~~~~~~~~~~~~~~~~~~~
../examples/server_node_efd/efd_server/main.c: In function ‘do_stats_display’:
../examples/server_node_efd/efd_server/main.c:86:59: note: format string is defined here
   86 |                                 RTE_ETHER_ADDR_PRT_FMT "\n",
      |

Fixes: 39aad0e88c58 ("examples/flow_distributor: new example to demonstrate EFD")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/server_node_efd/efd_server/main.c | 2 +-
 examples/server_node_efd/shared/common.h   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/examples/server_node_efd/efd_server/main.c b/examples/server_node_efd/efd_server/main.c
index 75ff0ea532..62c3f4a16d 100644
--- a/examples/server_node_efd/efd_server/main.c
+++ b/examples/server_node_efd/efd_server/main.c
@@ -68,7 +68,7 @@ static const char *
 get_printable_mac_addr(uint16_t port)
 {
 	static const char err_address[] = "00:00:00:00:00:00";
-	static char addresses[RTE_MAX_ETHPORTS][sizeof(err_address)];
+	static char addresses[RTE_MAX_ETHPORTS][RTE_ETHER_ADDR_FMT_SIZE + 1];
 	struct rte_ether_addr mac;
 	int ret;
 
diff --git a/examples/server_node_efd/shared/common.h b/examples/server_node_efd/shared/common.h
index e1ab7e62b7..6726e2031e 100644
--- a/examples/server_node_efd/shared/common.h
+++ b/examples/server_node_efd/shared/common.h
@@ -58,8 +58,9 @@ get_rx_queue_name(unsigned int id)
 	/*
 	 * Buffer for return value. Size calculated by %u being replaced
 	 * by maximum 3 digits (plus an extra byte for safety)
+	 * Used as ring name, so upper limit is ring name size.
 	 */
-	static char buffer[sizeof(MP_NODE_RXQ_NAME) + 2];
+	static char buffer[RTE_RING_NAMESIZE];
 
 	snprintf(buffer, sizeof(buffer), MP_NODE_RXQ_NAME, id);
 	return buffer;
-- 
2.51.0

[PATCH v3 2/4] examples/vdpa: fix format overflow warning

[Stephen Hemminger]

The ifname is limited to 128 characters, but it would allow up
to 128 characters as prefix then could overflow creating ifname.

Change to limit path prefix (iface) to 123 (128 - sizeof("1024"))
to avoid possible format overflow

../examples/vdpa/main.c:501:76: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
  501 |                         snprintf(vports[devcnt].ifname, MAX_PATH_LEN, "%s%d",
      |                                                                            ^
../examples/vdpa/main.c:501:25: note: ‘snprintf’ output between 2 and 139 bytes into a destination of size 128
  501 |                         snprintf(vports[devcnt].ifname, MAX_PATH_LEN, "%s%d",
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  502 |                                         iface, devcnt);
      |

Fixes: 38f8ab0bbc8d ("vhost: make vDPA framework bus agnostic")
Cc: maxime.coquelin@redhat.com
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 examples/vdpa/main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
index 289db26498..7fd0e55b20 100644
--- a/examples/vdpa/main.c
+++ b/examples/vdpa/main.c
@@ -22,6 +22,8 @@
 
 #define MAX_PATH_LEN 128
 #define MAX_VDPA_SAMPLE_PORTS 1024
+#define stringify(x) (#x)
+#define MAX_VDPA_STR_LEN sizeof(stringify(MAX_VDPA_SAMPLE_PORTS))
 #define RTE_LOGTYPE_VDPA RTE_LOGTYPE_USER1
 
 struct vdpa_port {
@@ -36,7 +38,7 @@ struct vdpa_port {
 
 static struct vdpa_port vports[MAX_VDPA_SAMPLE_PORTS];
 
-static char iface[MAX_PATH_LEN];
+static char iface[MAX_PATH_LEN - MAX_VDPA_STR_LEN];
 static int devcnt;
 static int interactive;
 static int client_mode;
@@ -74,9 +76,8 @@ parse_args(int argc, char **argv)
 			break;
 		/* long options */
 		case 0:
-			if (strncmp(long_option[idx].name, "iface",
-						MAX_PATH_LEN) == 0) {
-				rte_strscpy(iface, optarg, MAX_PATH_LEN);
+			if (!strcmp(long_option[idx].name, "iface")) {
+				rte_strscpy(iface, optarg, sizeof(iface));
 				printf("iface %s\n", iface);
 			}
 			if (!strcmp(long_option[idx].name, "interactive")) {
-- 
2.51.0

[PATCH v3 3/4] examples/ip_reassembly: add check before formatting name

[Stephen Hemminger]

In theory, lcore and queue could be so large that mbuf pool name
could overflow. But that can never happen since lcore and queue
will be in range. Add a check so that static tools know that.
Format overflow warnings seen on older versions of Gcc only.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 examples/ip_reassembly/main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
index 17ae76d4ba..25b904dbd4 100644
--- a/examples/ip_reassembly/main.c
+++ b/examples/ip_reassembly/main.c
@@ -884,6 +884,13 @@ setup_queue_tbl(struct rx_queue *rxq, uint32_t lcore, uint32_t queue)
 
 	nb_mbuf = RTE_MAX(nb_mbuf, (uint32_t)NB_MBUF);
 
+	/* Should never happen but check so that pool name won't be too long. */
+	if (lcore > RTE_MAX_LCORE || queue > RTE_MAX_QUEUES_PER_PORT) {
+		RTE_LOG(ERR, IP_RSMBL, "invalid lcore %u or queue %u",
+			lcore, queue);
+		return -1;
+	}
+
 	snprintf(buf, sizeof(buf), "mbuf_pool_%u_%u", lcore, queue);
 
 	rxq->pool = rte_pktmbuf_pool_create(buf, nb_mbuf, MEMPOOL_CACHE_SIZE, 0,
-- 
2.51.0

[PATCH v3 4/4] examples: enable format truncation warning

[Stephen Hemminger]

There were several hidden bugs in examples because format
truncation warning was disabled.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 examples/meson.build | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/examples/meson.build b/examples/meson.build
index 8e8968a1fa..25d9c88457 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -78,10 +78,9 @@ else
     examples = get_option('examples').split(',')
     allow_skips = false # error out if we can't build a requested app
 endif
+
 default_cflags = machine_args
-if cc.has_argument('-Wno-format-truncation')
-    default_cflags += '-Wno-format-truncation'
-endif
+
 default_ldflags = dpdk_extra_ldflags
 if get_option('default_library') == 'static' and not is_windows
     default_ldflags += ['-Wl,--export-dynamic']
-- 
2.51.0