[PATCH iproute2 v2 0/2] fix memory leak in get_task_name()

[PATCH iproute2 v2 0/2] fix memory leak in get_task_name()

[Andrea Claudi]

This series fixes some memory leaks related to the usage of the
get_task_name() function from lib/fs.c.

Patch 2/2 addresses a coverity warning related to this memory leak,
making the code a bit more readable by humans and coverity.

Changelog:
----------
v1 -> v2
- on Stephen's suggestion, drop asprintf() and use a local var for path;
  additionally drop %m from fscanf to not allocate memory, and resort to
  a param to return task name to the caller.
- patch 2/3 of the original series is no more needed.

Andrea Claudi (2):
  lib/fs: fix memory leak in get_task_name()
  rdma: make RES_PID and RES_KERN_NAME alternative to each other

 include/utils.h |  2 +-
 ip/iptuntap.c   | 17 ++++++++++-------
 lib/fs.c        | 20 ++++++++++----------
 rdma/res-cmid.c | 18 +++++++++---------
 rdma/res-cq.c   | 17 +++++++++--------
 rdma/res-ctx.c  | 16 ++++++++--------
 rdma/res-mr.c   | 15 ++++++++-------
 rdma/res-pd.c   | 17 +++++++++--------
 rdma/res-qp.c   | 16 ++++++++--------
 rdma/res-srq.c  | 17 +++++++++--------
 rdma/stat.c     | 14 +++++++++-----
 11 files changed, 90 insertions(+), 79 deletions(-)

-- 
2.35.1

[PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Andrea Claudi]

asprintf() allocates memory which is not freed on the error path of
get_task_name(), thus potentially leading to memory leaks.

Rework get_task_name() and avoid asprintf() usage and memory allocation,
returning the task string to the caller using an additional char*
parameter.

Fixes: 81bfd01a4c9e ("lib: move get_task_name() from rdma")
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
---
 include/utils.h |  2 +-
 ip/iptuntap.c   | 17 ++++++++++-------
 lib/fs.c        | 20 ++++++++++----------
 rdma/res-cmid.c |  8 +++++---
 rdma/res-cq.c   |  8 +++++---
 rdma/res-ctx.c  |  7 ++++---
 rdma/res-mr.c   |  7 ++++---
 rdma/res-pd.c   |  8 +++++---
 rdma/res-qp.c   |  7 ++++---
 rdma/res-srq.c  |  7 ++++---
 rdma/stat.c     |  5 ++++-
 11 files changed, 56 insertions(+), 40 deletions(-)

diff --git a/include/utils.h b/include/utils.h
index b6c468e9..81294488 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
 __u64 get_cgroup2_id(const char *path);
 char *get_cgroup2_path(__u64 id, bool full);
 int get_command_name(const char *pid, char *comm, size_t len);
-char *get_task_name(pid_t pid);
+int get_task_name(pid_t pid, char *name);
 
 int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
 			    struct rtattr *tb[]);
diff --git a/ip/iptuntap.c b/ip/iptuntap.c
index 385d2bd8..2ae6b1a1 100644
--- a/ip/iptuntap.c
+++ b/ip/iptuntap.c
@@ -321,14 +321,17 @@ static void show_processes(const char *name)
 			} else if (err == 2 &&
 				   !strcmp("iff", key) &&
 				   !strcmp(name, value)) {
-				char *pname = get_task_name(pid);
-
-				print_string(PRINT_ANY, "name",
-					     "%s", pname ? : "<NULL>");
+				SPRINT_BUF(pname);
+
+				if (get_task_name(pid, pname)) {
+					print_string(PRINT_ANY, "name",
+						     "%s", "<NULL>");
+				} else {
+					print_string(PRINT_ANY, "name",
+						     "%s", pname);
+				}
 
-				print_uint(PRINT_ANY, "pid",
-					   "(%d)", pid);
-				free(pname);
+				print_uint(PRINT_ANY, "pid", "(%d)", pid);
 			}
 
 			free(key);
diff --git a/lib/fs.c b/lib/fs.c
index f6f5f8a0..03df0f6a 100644
--- a/lib/fs.c
+++ b/lib/fs.c
@@ -342,25 +342,25 @@ int get_command_name(const char *pid, char *comm, size_t len)
 	return 0;
 }
 
-char *get_task_name(pid_t pid)
+int get_task_name(pid_t pid, char *name)
 {
-	char *comm;
+	char path[PATH_MAX];
 	FILE *f;
 
 	if (!pid)
-		return NULL;
+		return -1;
 
-	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
-		return NULL;
+	if (snprintf(path, sizeof(path), "/proc/%d/comm", pid) >= sizeof(path))
+		return -1;
 
-	f = fopen(comm, "r");
+	f = fopen(path, "r");
 	if (!f)
-		return NULL;
+		return -1;
 
-	if (fscanf(f, "%ms\n", &comm) != 1)
-		comm = NULL;
+	if (fscanf(f, "%s\n", name) != 1)
+		return -1;
 
 	fclose(f);
 
-	return comm;
+	return 0;
 }
diff --git a/rdma/res-cmid.c b/rdma/res-cmid.c
index bfaa47b5..3475349d 100644
--- a/rdma/res-cmid.c
+++ b/rdma/res-cmid.c
@@ -159,8 +159,11 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
 		goto out;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -199,8 +202,7 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
 	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
 	newline(rd);
 
-out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
+out:
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-cq.c b/rdma/res-cq.c
index 9e7c4f51..5ed455ea 100644
--- a/rdma/res-cq.c
+++ b/rdma/res-cq.c
@@ -84,8 +84,11 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
 		goto out;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -123,8 +126,7 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
 	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
 	newline(rd);
 
-out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
+out:
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-ctx.c b/rdma/res-ctx.c
index 30afe97a..fbd52dd5 100644
--- a/rdma/res-ctx.c
+++ b/rdma/res-ctx.c
@@ -18,8 +18,11 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
 		return MNL_CB_ERROR;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -48,8 +51,6 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
 	newline(rd);
 
 out:
-	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-mr.c b/rdma/res-mr.c
index 1bf73f3a..6a59d9e4 100644
--- a/rdma/res-mr.c
+++ b/rdma/res-mr.c
@@ -47,8 +47,11 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
 		goto out;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -87,8 +90,6 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
 	newline(rd);
 
 out:
-	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-pd.c b/rdma/res-pd.c
index df538010..a51bb634 100644
--- a/rdma/res-pd.c
+++ b/rdma/res-pd.c
@@ -34,8 +34,11 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
 			nla_line[RDMA_NLDEV_ATTR_RES_UNSAFE_GLOBAL_RKEY]);
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -76,8 +79,7 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
 	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
 	newline(rd);
 
-out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
+out:
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-qp.c b/rdma/res-qp.c
index a38be399..575e0529 100644
--- a/rdma/res-qp.c
+++ b/rdma/res-qp.c
@@ -146,8 +146,11 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
 		goto out;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -179,8 +182,6 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
 	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
 	newline(rd);
 out:
-	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/res-srq.c b/rdma/res-srq.c
index 3038c352..945109fc 100644
--- a/rdma/res-srq.c
+++ b/rdma/res-srq.c
@@ -174,8 +174,11 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
 		return MNL_CB_ERROR;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 	if (rd_is_filtered_attr(rd, "pid", pid,
 				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
@@ -228,8 +231,6 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
 	newline(rd);
 
 out:
-	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
-		free(comm);
 	return MNL_CB_OK;
 }
 
diff --git a/rdma/stat.c b/rdma/stat.c
index adfcd34a..a63b70a4 100644
--- a/rdma/stat.c
+++ b/rdma/stat.c
@@ -248,8 +248,11 @@ static int res_counter_line(struct rd *rd, const char *name, int index,
 		return MNL_CB_OK;
 
 	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
+		SPRINT_BUF(b);
+
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
-		comm = get_task_name(pid);
+		if (!get_task_name(pid, b))
+			comm = b;
 	}
 	if (rd_is_filtered_attr(rd, "pid", pid,
 				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
-- 
2.35.1

[PATCH iproute2 v2 2/2] rdma: make RES_PID and RES_KERN_NAME alternative to each other

[Andrea Claudi]

RDMA_NLDEV_ATTR_RES_PID and RDMA_NLDEV_ATTR_RES_KERN_NAME cannot be set
together, as evident for the fill_res_name_pid() function in the kernel
infiniband driver. This commit makes this clear at first glance, using
an else branch for the RDMA_NLDEV_ATTR_RES_KERN_NAME case.

This also helps coverity to better understand this code and avoid
producing a bogus warning complaining about mnl_attr_get_str overwriting
comme, and thus leaking the storage that comm points to.

Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
---
 rdma/res-cmid.c | 10 ++++------
 rdma/res-cq.c   |  9 ++++-----
 rdma/res-ctx.c  |  9 ++++-----
 rdma/res-mr.c   |  8 ++++----
 rdma/res-pd.c   |  9 ++++-----
 rdma/res-qp.c   |  9 ++++-----
 rdma/res-srq.c  | 10 +++++-----
 rdma/stat.c     |  9 +++++----
 8 files changed, 34 insertions(+), 39 deletions(-)

diff --git a/rdma/res-cmid.c b/rdma/res-cmid.c
index 3475349d..3abc5b42 100644
--- a/rdma/res-cmid.c
+++ b/rdma/res-cmid.c
@@ -164,6 +164,10 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -176,12 +180,6 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
 				nla_line[RDMA_NLDEV_ATTR_RES_CM_IDN]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-	}
-
 	open_json_object(NULL);
 	print_link(rd, idx, name, port, nla_line);
 	res_print_uint(rd, "cm-idn", cm_idn,
diff --git a/rdma/res-cq.c b/rdma/res-cq.c
index 5ed455ea..e691f21f 100644
--- a/rdma/res-cq.c
+++ b/rdma/res-cq.c
@@ -89,6 +89,10 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -106,11 +110,6 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
 				nla_line[RDMA_NLDEV_ATTR_RES_CTXN]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	open_json_object(NULL);
 	print_dev(rd, idx, name);
 	res_print_uint(rd, "cqn", cqn, nla_line[RDMA_NLDEV_ATTR_RES_CQN]);
diff --git a/rdma/res-ctx.c b/rdma/res-ctx.c
index fbd52dd5..e300f605 100644
--- a/rdma/res-ctx.c
+++ b/rdma/res-ctx.c
@@ -23,6 +23,10 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -36,11 +40,6 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
 				nla_line[RDMA_NLDEV_ATTR_RES_CTXN]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	open_json_object(NULL);
 	print_dev(rd, idx, name);
 	res_print_uint(rd, "ctxn", ctxn, nla_line[RDMA_NLDEV_ATTR_RES_CTXN]);
diff --git a/rdma/res-mr.c b/rdma/res-mr.c
index 6a59d9e4..f3a86cac 100644
--- a/rdma/res-mr.c
+++ b/rdma/res-mr.c
@@ -52,6 +52,10 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -70,10 +74,6 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
 				nla_line[RDMA_NLDEV_ATTR_RES_PDN]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	open_json_object(NULL);
 	print_dev(rd, idx, name);
 	res_print_uint(rd, "mrn", mrn, nla_line[RDMA_NLDEV_ATTR_RES_MRN]);
diff --git a/rdma/res-pd.c b/rdma/res-pd.c
index a51bb634..7ab3ac6b 100644
--- a/rdma/res-pd.c
+++ b/rdma/res-pd.c
@@ -39,6 +39,10 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
@@ -58,11 +62,6 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
 				nla_line[RDMA_NLDEV_ATTR_RES_PDN]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	open_json_object(NULL);
 	print_dev(rd, idx, name);
 	res_print_uint(rd, "pdn", pdn, nla_line[RDMA_NLDEV_ATTR_RES_PDN]);
diff --git a/rdma/res-qp.c b/rdma/res-qp.c
index 575e0529..d15522e8 100644
--- a/rdma/res-qp.c
+++ b/rdma/res-qp.c
@@ -151,17 +151,16 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
 
 	if (rd_is_filtered_attr(rd, "pid", pid,
 				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	open_json_object(NULL);
 	print_link(rd, idx, name, port, nla_line);
 	res_print_uint(rd, "lqpn", lqpn, nla_line[RDMA_NLDEV_ATTR_RES_LQPN]);
diff --git a/rdma/res-srq.c b/rdma/res-srq.c
index 945109fc..2944ee4a 100644
--- a/rdma/res-srq.c
+++ b/rdma/res-srq.c
@@ -179,7 +179,12 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
+
 	if (rd_is_filtered_attr(rd, "pid", pid,
 				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
 		goto out;
@@ -212,11 +217,6 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
 			MNL_CB_OK)
 		goto out;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		/* discard const from mnl_attr_get_str */
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	open_json_object(NULL);
 	print_dev(rd, idx, name);
 	res_print_uint(rd, "srqn", srqn, nla_line[RDMA_NLDEV_ATTR_RES_SRQN]);
diff --git a/rdma/stat.c b/rdma/stat.c
index a63b70a4..fe66f4d0 100644
--- a/rdma/stat.c
+++ b/rdma/stat.c
@@ -253,15 +253,16 @@ static int res_counter_line(struct rd *rd, const char *name, int index,
 		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
 		if (!get_task_name(pid, b))
 			comm = b;
+	} else if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]) {
+		/* discard const from mnl_attr_get_str */
+		comm = (char *)mnl_attr_get_str(
+			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
 	}
+
 	if (rd_is_filtered_attr(rd, "pid", pid,
 				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
 		return MNL_CB_OK;
 
-	if (nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME])
-		comm = (char *)mnl_attr_get_str(
-			nla_line[RDMA_NLDEV_ATTR_RES_KERN_NAME]);
-
 	mnl_attr_for_each_nested(nla_entry, qp_table) {
 		struct nlattr *qp_line[RDMA_NLDEV_ATTR_MAX] = {};
 
-- 
2.35.1

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Leon Romanovsky]

On Wed, Mar 02, 2022 at 01:28:47PM +0100, Andrea Claudi wrote:
> asprintf() allocates memory which is not freed on the error path of
> get_task_name(), thus potentially leading to memory leaks.

Not really, memory is released when the application exits, which is the
case here.

> 
> Rework get_task_name() and avoid asprintf() usage and memory allocation,
> returning the task string to the caller using an additional char*
> parameter.
> 
> Fixes: 81bfd01a4c9e ("lib: move get_task_name() from rdma")

As I was told before, in netdev Fixes means that it is a bug that
affects users. This is not the case here.

> Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
> ---
>  include/utils.h |  2 +-
>  ip/iptuntap.c   | 17 ++++++++++-------
>  lib/fs.c        | 20 ++++++++++----------
>  rdma/res-cmid.c |  8 +++++---
>  rdma/res-cq.c   |  8 +++++---
>  rdma/res-ctx.c  |  7 ++++---
>  rdma/res-mr.c   |  7 ++++---
>  rdma/res-pd.c   |  8 +++++---
>  rdma/res-qp.c   |  7 ++++---
>  rdma/res-srq.c  |  7 ++++---
>  rdma/stat.c     |  5 ++++-
>  11 files changed, 56 insertions(+), 40 deletions(-)

Honestly, I don't see any need in both patches.

Thanks

> 
> diff --git a/include/utils.h b/include/utils.h
> index b6c468e9..81294488 100644
> --- a/include/utils.h
> +++ b/include/utils.h
> @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
>  __u64 get_cgroup2_id(const char *path);
>  char *get_cgroup2_path(__u64 id, bool full);
>  int get_command_name(const char *pid, char *comm, size_t len);
> -char *get_task_name(pid_t pid);
> +int get_task_name(pid_t pid, char *name);
>  
>  int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
>  			    struct rtattr *tb[]);
> diff --git a/ip/iptuntap.c b/ip/iptuntap.c
> index 385d2bd8..2ae6b1a1 100644
> --- a/ip/iptuntap.c
> +++ b/ip/iptuntap.c
> @@ -321,14 +321,17 @@ static void show_processes(const char *name)
>  			} else if (err == 2 &&
>  				   !strcmp("iff", key) &&
>  				   !strcmp(name, value)) {
> -				char *pname = get_task_name(pid);
> -
> -				print_string(PRINT_ANY, "name",
> -					     "%s", pname ? : "<NULL>");
> +				SPRINT_BUF(pname);
> +
> +				if (get_task_name(pid, pname)) {
> +					print_string(PRINT_ANY, "name",
> +						     "%s", "<NULL>");
> +				} else {
> +					print_string(PRINT_ANY, "name",
> +						     "%s", pname);
> +				}
>  
> -				print_uint(PRINT_ANY, "pid",
> -					   "(%d)", pid);
> -				free(pname);
> +				print_uint(PRINT_ANY, "pid", "(%d)", pid);
>  			}
>  
>  			free(key);
> diff --git a/lib/fs.c b/lib/fs.c
> index f6f5f8a0..03df0f6a 100644
> --- a/lib/fs.c
> +++ b/lib/fs.c
> @@ -342,25 +342,25 @@ int get_command_name(const char *pid, char *comm, size_t len)
>  	return 0;
>  }
>  
> -char *get_task_name(pid_t pid)
> +int get_task_name(pid_t pid, char *name)
>  {
> -	char *comm;
> +	char path[PATH_MAX];
>  	FILE *f;
>  
>  	if (!pid)
> -		return NULL;
> +		return -1;
>  
> -	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
> -		return NULL;
> +	if (snprintf(path, sizeof(path), "/proc/%d/comm", pid) >= sizeof(path))
> +		return -1;
>  
> -	f = fopen(comm, "r");
> +	f = fopen(path, "r");
>  	if (!f)
> -		return NULL;
> +		return -1;
>  
> -	if (fscanf(f, "%ms\n", &comm) != 1)
> -		comm = NULL;
> +	if (fscanf(f, "%s\n", name) != 1)
> +		return -1;
>  
>  	fclose(f);
>  
> -	return comm;
> +	return 0;
>  }
> diff --git a/rdma/res-cmid.c b/rdma/res-cmid.c
> index bfaa47b5..3475349d 100644
> --- a/rdma/res-cmid.c
> +++ b/rdma/res-cmid.c
> @@ -159,8 +159,11 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
>  		goto out;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -199,8 +202,7 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
>  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
>  	newline(rd);
>  
> -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
> +out:
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-cq.c b/rdma/res-cq.c
> index 9e7c4f51..5ed455ea 100644
> --- a/rdma/res-cq.c
> +++ b/rdma/res-cq.c
> @@ -84,8 +84,11 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
>  		goto out;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -123,8 +126,7 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
>  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
>  	newline(rd);
>  
> -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
> +out:
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-ctx.c b/rdma/res-ctx.c
> index 30afe97a..fbd52dd5 100644
> --- a/rdma/res-ctx.c
> +++ b/rdma/res-ctx.c
> @@ -18,8 +18,11 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
>  		return MNL_CB_ERROR;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -48,8 +51,6 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
>  	newline(rd);
>  
>  out:
> -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-mr.c b/rdma/res-mr.c
> index 1bf73f3a..6a59d9e4 100644
> --- a/rdma/res-mr.c
> +++ b/rdma/res-mr.c
> @@ -47,8 +47,11 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
>  		goto out;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -87,8 +90,6 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
>  	newline(rd);
>  
>  out:
> -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-pd.c b/rdma/res-pd.c
> index df538010..a51bb634 100644
> --- a/rdma/res-pd.c
> +++ b/rdma/res-pd.c
> @@ -34,8 +34,11 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
>  			nla_line[RDMA_NLDEV_ATTR_RES_UNSAFE_GLOBAL_RKEY]);
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -76,8 +79,7 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
>  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
>  	newline(rd);
>  
> -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
> +out:
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-qp.c b/rdma/res-qp.c
> index a38be399..575e0529 100644
> --- a/rdma/res-qp.c
> +++ b/rdma/res-qp.c
> @@ -146,8 +146,11 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
>  		goto out;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  
>  	if (rd_is_filtered_attr(rd, "pid", pid,
> @@ -179,8 +182,6 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
>  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
>  	newline(rd);
>  out:
> -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/res-srq.c b/rdma/res-srq.c
> index 3038c352..945109fc 100644
> --- a/rdma/res-srq.c
> +++ b/rdma/res-srq.c
> @@ -174,8 +174,11 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
>  		return MNL_CB_ERROR;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  	if (rd_is_filtered_attr(rd, "pid", pid,
>  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> @@ -228,8 +231,6 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
>  	newline(rd);
>  
>  out:
> -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> -		free(comm);
>  	return MNL_CB_OK;
>  }
>  
> diff --git a/rdma/stat.c b/rdma/stat.c
> index adfcd34a..a63b70a4 100644
> --- a/rdma/stat.c
> +++ b/rdma/stat.c
> @@ -248,8 +248,11 @@ static int res_counter_line(struct rd *rd, const char *name, int index,
>  		return MNL_CB_OK;
>  
>  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> +		SPRINT_BUF(b);
> +
>  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> -		comm = get_task_name(pid);
> +		if (!get_task_name(pid, b))
> +			comm = b;
>  	}
>  	if (rd_is_filtered_attr(rd, "pid", pid,
>  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> -- 
> 2.35.1
> 

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[David Ahern]

On 3/2/22 5:28 AM, Andrea Claudi wrote:
> diff --git a/include/utils.h b/include/utils.h
> index b6c468e9..81294488 100644
> --- a/include/utils.h
> +++ b/include/utils.h
> @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
>  __u64 get_cgroup2_id(const char *path);
>  char *get_cgroup2_path(__u64 id, bool full);
>  int get_command_name(const char *pid, char *comm, size_t len);
> -char *get_task_name(pid_t pid);
> +int get_task_name(pid_t pid, char *name);
>  

changing to an API with an assumed length is not better than the current
situation. Why not just fixup the callers as needed to free the allocation?

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Andrea Claudi]

Hi Leon,
Thanks for your review.

On Thu, Mar 03, 2022 at 08:56:57PM +0200, Leon Romanovsky wrote:
> On Wed, Mar 02, 2022 at 01:28:47PM +0100, Andrea Claudi wrote:
> > asprintf() allocates memory which is not freed on the error path of
> > get_task_name(), thus potentially leading to memory leaks.
> 
> Not really, memory is released when the application exits, which is the
> case here.
>

That's certainly true. However this is still a leak in the time frame
between get_task_name function call and the application exit. For
example:

$ ip -d -b - << EOF
tuntap show
monitor
EOF

calls get_task_name one or more time (once for each tun interface), and
leaks memory indefinitely, if ip is not interrupted in some way.

Of course this is a corner case, and the leaks should anyway be small.
However I cannot see this as a good reason not to fix it.

> > 
> > Rework get_task_name() and avoid asprintf() usage and memory allocation,
> > returning the task string to the caller using an additional char*
> > parameter.
> > 
> > Fixes: 81bfd01a4c9e ("lib: move get_task_name() from rdma")
> 
> As I was told before, in netdev Fixes means that it is a bug that
> affects users. This is not the case here.

Thanks for letting me know. I usually rely a lot on Fixes: as iproute2
package maintainer, but I'll change my habits if this is the common
understanding. Stephen, David, WDYT?

> 
> > Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
> > ---
> >  include/utils.h |  2 +-
> >  ip/iptuntap.c   | 17 ++++++++++-------
> >  lib/fs.c        | 20 ++++++++++----------
> >  rdma/res-cmid.c |  8 +++++---
> >  rdma/res-cq.c   |  8 +++++---
> >  rdma/res-ctx.c  |  7 ++++---
> >  rdma/res-mr.c   |  7 ++++---
> >  rdma/res-pd.c   |  8 +++++---
> >  rdma/res-qp.c   |  7 ++++---
> >  rdma/res-srq.c  |  7 ++++---
> >  rdma/stat.c     |  5 ++++-
> >  11 files changed, 56 insertions(+), 40 deletions(-)
> 
> Honestly, I don't see any need in both patches.
> 
> Thanks
> 
> > 
> > diff --git a/include/utils.h b/include/utils.h
> > index b6c468e9..81294488 100644
> > --- a/include/utils.h
> > +++ b/include/utils.h
> > @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
> >  __u64 get_cgroup2_id(const char *path);
> >  char *get_cgroup2_path(__u64 id, bool full);
> >  int get_command_name(const char *pid, char *comm, size_t len);
> > -char *get_task_name(pid_t pid);
> > +int get_task_name(pid_t pid, char *name);
> >  
> >  int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
> >  			    struct rtattr *tb[]);
> > diff --git a/ip/iptuntap.c b/ip/iptuntap.c
> > index 385d2bd8..2ae6b1a1 100644
> > --- a/ip/iptuntap.c
> > +++ b/ip/iptuntap.c
> > @@ -321,14 +321,17 @@ static void show_processes(const char *name)
> >  			} else if (err == 2 &&
> >  				   !strcmp("iff", key) &&
> >  				   !strcmp(name, value)) {
> > -				char *pname = get_task_name(pid);
> > -
> > -				print_string(PRINT_ANY, "name",
> > -					     "%s", pname ? : "<NULL>");
> > +				SPRINT_BUF(pname);
> > +
> > +				if (get_task_name(pid, pname)) {
> > +					print_string(PRINT_ANY, "name",
> > +						     "%s", "<NULL>");
> > +				} else {
> > +					print_string(PRINT_ANY, "name",
> > +						     "%s", pname);
> > +				}
> >  
> > -				print_uint(PRINT_ANY, "pid",
> > -					   "(%d)", pid);
> > -				free(pname);
> > +				print_uint(PRINT_ANY, "pid", "(%d)", pid);
> >  			}
> >  
> >  			free(key);
> > diff --git a/lib/fs.c b/lib/fs.c
> > index f6f5f8a0..03df0f6a 100644
> > --- a/lib/fs.c
> > +++ b/lib/fs.c
> > @@ -342,25 +342,25 @@ int get_command_name(const char *pid, char *comm, size_t len)
> >  	return 0;
> >  }
> >  
> > -char *get_task_name(pid_t pid)
> > +int get_task_name(pid_t pid, char *name)
> >  {
> > -	char *comm;
> > +	char path[PATH_MAX];
> >  	FILE *f;
> >  
> >  	if (!pid)
> > -		return NULL;
> > +		return -1;
> >  
> > -	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
> > -		return NULL;
> > +	if (snprintf(path, sizeof(path), "/proc/%d/comm", pid) >= sizeof(path))
> > +		return -1;
> >  
> > -	f = fopen(comm, "r");
> > +	f = fopen(path, "r");
> >  	if (!f)
> > -		return NULL;
> > +		return -1;
> >  
> > -	if (fscanf(f, "%ms\n", &comm) != 1)
> > -		comm = NULL;
> > +	if (fscanf(f, "%s\n", name) != 1)
> > +		return -1;
> >  
> >  	fclose(f);
> >  
> > -	return comm;
> > +	return 0;
> >  }
> > diff --git a/rdma/res-cmid.c b/rdma/res-cmid.c
> > index bfaa47b5..3475349d 100644
> > --- a/rdma/res-cmid.c
> > +++ b/rdma/res-cmid.c
> > @@ -159,8 +159,11 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
> >  		goto out;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -199,8 +202,7 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
> >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> >  	newline(rd);
> >  
> > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> > +out:
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-cq.c b/rdma/res-cq.c
> > index 9e7c4f51..5ed455ea 100644
> > --- a/rdma/res-cq.c
> > +++ b/rdma/res-cq.c
> > @@ -84,8 +84,11 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
> >  		goto out;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -123,8 +126,7 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
> >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> >  	newline(rd);
> >  
> > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> > +out:
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-ctx.c b/rdma/res-ctx.c
> > index 30afe97a..fbd52dd5 100644
> > --- a/rdma/res-ctx.c
> > +++ b/rdma/res-ctx.c
> > @@ -18,8 +18,11 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
> >  		return MNL_CB_ERROR;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -48,8 +51,6 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
> >  	newline(rd);
> >  
> >  out:
> > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-mr.c b/rdma/res-mr.c
> > index 1bf73f3a..6a59d9e4 100644
> > --- a/rdma/res-mr.c
> > +++ b/rdma/res-mr.c
> > @@ -47,8 +47,11 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
> >  		goto out;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -87,8 +90,6 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
> >  	newline(rd);
> >  
> >  out:
> > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-pd.c b/rdma/res-pd.c
> > index df538010..a51bb634 100644
> > --- a/rdma/res-pd.c
> > +++ b/rdma/res-pd.c
> > @@ -34,8 +34,11 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
> >  			nla_line[RDMA_NLDEV_ATTR_RES_UNSAFE_GLOBAL_RKEY]);
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -76,8 +79,7 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
> >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> >  	newline(rd);
> >  
> > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> > +out:
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-qp.c b/rdma/res-qp.c
> > index a38be399..575e0529 100644
> > --- a/rdma/res-qp.c
> > +++ b/rdma/res-qp.c
> > @@ -146,8 +146,11 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
> >  		goto out;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > @@ -179,8 +182,6 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
> >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> >  	newline(rd);
> >  out:
> > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/res-srq.c b/rdma/res-srq.c
> > index 3038c352..945109fc 100644
> > --- a/rdma/res-srq.c
> > +++ b/rdma/res-srq.c
> > @@ -174,8 +174,11 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
> >  		return MNL_CB_ERROR;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> >  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> > @@ -228,8 +231,6 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
> >  	newline(rd);
> >  
> >  out:
> > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > -		free(comm);
> >  	return MNL_CB_OK;
> >  }
> >  
> > diff --git a/rdma/stat.c b/rdma/stat.c
> > index adfcd34a..a63b70a4 100644
> > --- a/rdma/stat.c
> > +++ b/rdma/stat.c
> > @@ -248,8 +248,11 @@ static int res_counter_line(struct rd *rd, const char *name, int index,
> >  		return MNL_CB_OK;
> >  
> >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > +		SPRINT_BUF(b);
> > +
> >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > -		comm = get_task_name(pid);
> > +		if (!get_task_name(pid, b))
> > +			comm = b;
> >  	}
> >  	if (rd_is_filtered_attr(rd, "pid", pid,
> >  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> > -- 
> > 2.35.1
> > 
> 

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[David Ahern]

On 3/7/22 11:07 AM, Andrea Claudi wrote:
> Thanks for letting me know. I usually rely a lot on Fixes: as iproute2
> package maintainer, but I'll change my habits if this is the common
> understanding. Stephen, David, WDYT?

I think a Fixes tag is relevant here.

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Stephen Hemminger]

On Mon, 7 Mar 2022 10:58:37 -0700
David Ahern <dsahern@kernel.org> wrote:

> On 3/2/22 5:28 AM, Andrea Claudi wrote:
> > diff --git a/include/utils.h b/include/utils.h
> > index b6c468e9..81294488 100644
> > --- a/include/utils.h
> > +++ b/include/utils.h
> > @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
> >  __u64 get_cgroup2_id(const char *path);
> >  char *get_cgroup2_path(__u64 id, bool full);
> >  int get_command_name(const char *pid, char *comm, size_t len);
> > -char *get_task_name(pid_t pid);
> > +int get_task_name(pid_t pid, char *name);
> >    
> 
> changing to an API with an assumed length is not better than the current
> situation. Why not just fixup the callers as needed to free the allocation?

I wonder if iproute2 should start using GCC attribute cleanup function
(like systemd) or would this be too much of using a new thing?

Not sure if using the attribute (wrapped in macro) just hides the problem

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Andrea Claudi]

On Mon, Mar 07, 2022 at 10:58:37AM -0700, David Ahern wrote:
> On 3/2/22 5:28 AM, Andrea Claudi wrote:
> > diff --git a/include/utils.h b/include/utils.h
> > index b6c468e9..81294488 100644
> > --- a/include/utils.h
> > +++ b/include/utils.h
> > @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
> >  __u64 get_cgroup2_id(const char *path);
> >  char *get_cgroup2_path(__u64 id, bool full);
> >  int get_command_name(const char *pid, char *comm, size_t len);
> > -char *get_task_name(pid_t pid);
> > +int get_task_name(pid_t pid, char *name);
> >  
> 
> changing to an API with an assumed length is not better than the current
> situation. Why not just fixup the callers as needed to free the allocation?
>

I actually did that on v1. After Stephen's comment about asprintf(), I
got the idea to make get_task_name() similar to get_command_name() and
a bit more "user-friendly", so that callers do not need a free().

If you think this is not ideal, I can post a v3 with the necessary fixes
to the callers.

Thanks,
Andrea

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Stephen Hemminger]

On Mon, 7 Mar 2022 19:21:41 +0100
Andrea Claudi <aclaudi@redhat.com> wrote:

> On Mon, Mar 07, 2022 at 10:58:37AM -0700, David Ahern wrote:
> > On 3/2/22 5:28 AM, Andrea Claudi wrote:  
> > > diff --git a/include/utils.h b/include/utils.h
> > > index b6c468e9..81294488 100644
> > > --- a/include/utils.h
> > > +++ b/include/utils.h
> > > @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
> > >  __u64 get_cgroup2_id(const char *path);
> > >  char *get_cgroup2_path(__u64 id, bool full);
> > >  int get_command_name(const char *pid, char *comm, size_t len);
> > > -char *get_task_name(pid_t pid);
> > > +int get_task_name(pid_t pid, char *name);
> > >    
> > 
> > changing to an API with an assumed length is not better than the current
> > situation. Why not just fixup the callers as needed to free the allocation?
> >  
> 
> I actually did that on v1. After Stephen's comment about asprintf(), I
> got the idea to make get_task_name() similar to get_command_name() and
> a bit more "user-friendly", so that callers do not need a free().
> 
> If you think this is not ideal, I can post a v3 with the necessary fixes
> to the callers.
> 
> Thanks,
> Andrea
> 

My comment was purely a suggestion not a requirement.
I have just had issues with complaints from compiler about code not
checking return value from asprintf, so tend to avoid it.

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[David Ahern]

On 3/7/22 11:21 AM, Andrea Claudi wrote:
> On Mon, Mar 07, 2022 at 10:58:37AM -0700, David Ahern wrote:
>> On 3/2/22 5:28 AM, Andrea Claudi wrote:
>>> diff --git a/include/utils.h b/include/utils.h
>>> index b6c468e9..81294488 100644
>>> --- a/include/utils.h
>>> +++ b/include/utils.h
>>> @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
>>>  __u64 get_cgroup2_id(const char *path);
>>>  char *get_cgroup2_path(__u64 id, bool full);
>>>  int get_command_name(const char *pid, char *comm, size_t len);
>>> -char *get_task_name(pid_t pid);
>>> +int get_task_name(pid_t pid, char *name);
>>>  
>>
>> changing to an API with an assumed length is not better than the current
>> situation. Why not just fixup the callers as needed to free the allocation?
>>
> 
> I actually did that on v1. After Stephen's comment about asprintf(), I
> got the idea to make get_task_name() similar to get_command_name() and
> a bit more "user-friendly", so that callers do not need a free().
> 

get_command_name passes a buffer and length. That's a better API - no
assumptions.

Re: [PATCH iproute2 v2 1/2] lib/fs: fix memory leak in get_task_name()

[Leon Romanovsky]

On Mon, Mar 07, 2022 at 07:07:10PM +0100, Andrea Claudi wrote:
> Hi Leon,
> Thanks for your review.
> 
> On Thu, Mar 03, 2022 at 08:56:57PM +0200, Leon Romanovsky wrote:
> > On Wed, Mar 02, 2022 at 01:28:47PM +0100, Andrea Claudi wrote:
> > > asprintf() allocates memory which is not freed on the error path of
> > > get_task_name(), thus potentially leading to memory leaks.
> > 
> > Not really, memory is released when the application exits, which is the
> > case here.
> >
> 
> That's certainly true. However this is still a leak in the time frame
> between get_task_name function call and the application exit. For
> example:
> 
> $ ip -d -b - << EOF
> tuntap show
> monitor
> EOF
> 
> calls get_task_name one or more time (once for each tun interface), and
> leaks memory indefinitely, if ip is not interrupted in some way.
> 
> Of course this is a corner case, and the leaks should anyway be small.
> However I cannot see this as a good reason not to fix it.
> 
> > > 
> > > Rework get_task_name() and avoid asprintf() usage and memory allocation,
> > > returning the task string to the caller using an additional char*
> > > parameter.
> > > 
> > > Fixes: 81bfd01a4c9e ("lib: move get_task_name() from rdma")
> > 
> > As I was told before, in netdev Fixes means that it is a bug that
> > affects users. This is not the case here.
> 
> Thanks for letting me know. I usually rely a lot on Fixes: as iproute2
> package maintainer, but I'll change my habits if this is the common
> understanding. Stephen, David, WDYT?
> 
> > 
> > > Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
> > > ---
> > >  include/utils.h |  2 +-
> > >  ip/iptuntap.c   | 17 ++++++++++-------

Ahh, sorry, I missed this user.
So yes, Fixes is needed here.

Thanks

> > >  lib/fs.c        | 20 ++++++++++----------
> > >  rdma/res-cmid.c |  8 +++++---
> > >  rdma/res-cq.c   |  8 +++++---
> > >  rdma/res-ctx.c  |  7 ++++---
> > >  rdma/res-mr.c   |  7 ++++---
> > >  rdma/res-pd.c   |  8 +++++---
> > >  rdma/res-qp.c   |  7 ++++---
> > >  rdma/res-srq.c  |  7 ++++---
> > >  rdma/stat.c     |  5 ++++-
> > >  11 files changed, 56 insertions(+), 40 deletions(-)
> > 
> > Honestly, I don't see any need in both patches.
> > 
> > Thanks
> > 
> > > 
> > > diff --git a/include/utils.h b/include/utils.h
> > > index b6c468e9..81294488 100644
> > > --- a/include/utils.h
> > > +++ b/include/utils.h
> > > @@ -307,7 +307,7 @@ char *find_cgroup2_mount(bool do_mount);
> > >  __u64 get_cgroup2_id(const char *path);
> > >  char *get_cgroup2_path(__u64 id, bool full);
> > >  int get_command_name(const char *pid, char *comm, size_t len);
> > > -char *get_task_name(pid_t pid);
> > > +int get_task_name(pid_t pid, char *name);
> > >  
> > >  int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
> > >  			    struct rtattr *tb[]);
> > > diff --git a/ip/iptuntap.c b/ip/iptuntap.c
> > > index 385d2bd8..2ae6b1a1 100644
> > > --- a/ip/iptuntap.c
> > > +++ b/ip/iptuntap.c
> > > @@ -321,14 +321,17 @@ static void show_processes(const char *name)
> > >  			} else if (err == 2 &&
> > >  				   !strcmp("iff", key) &&
> > >  				   !strcmp(name, value)) {
> > > -				char *pname = get_task_name(pid);
> > > -
> > > -				print_string(PRINT_ANY, "name",
> > > -					     "%s", pname ? : "<NULL>");
> > > +				SPRINT_BUF(pname);
> > > +
> > > +				if (get_task_name(pid, pname)) {
> > > +					print_string(PRINT_ANY, "name",
> > > +						     "%s", "<NULL>");
> > > +				} else {
> > > +					print_string(PRINT_ANY, "name",
> > > +						     "%s", pname);
> > > +				}
> > >  
> > > -				print_uint(PRINT_ANY, "pid",
> > > -					   "(%d)", pid);
> > > -				free(pname);
> > > +				print_uint(PRINT_ANY, "pid", "(%d)", pid);
> > >  			}
> > >  
> > >  			free(key);
> > > diff --git a/lib/fs.c b/lib/fs.c
> > > index f6f5f8a0..03df0f6a 100644
> > > --- a/lib/fs.c
> > > +++ b/lib/fs.c
> > > @@ -342,25 +342,25 @@ int get_command_name(const char *pid, char *comm, size_t len)
> > >  	return 0;
> > >  }
> > >  
> > > -char *get_task_name(pid_t pid)
> > > +int get_task_name(pid_t pid, char *name)
> > >  {
> > > -	char *comm;
> > > +	char path[PATH_MAX];
> > >  	FILE *f;
> > >  
> > >  	if (!pid)
> > > -		return NULL;
> > > +		return -1;
> > >  
> > > -	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
> > > -		return NULL;
> > > +	if (snprintf(path, sizeof(path), "/proc/%d/comm", pid) >= sizeof(path))
> > > +		return -1;
> > >  
> > > -	f = fopen(comm, "r");
> > > +	f = fopen(path, "r");
> > >  	if (!f)
> > > -		return NULL;
> > > +		return -1;
> > >  
> > > -	if (fscanf(f, "%ms\n", &comm) != 1)
> > > -		comm = NULL;
> > > +	if (fscanf(f, "%s\n", name) != 1)
> > > +		return -1;
> > >  
> > >  	fclose(f);
> > >  
> > > -	return comm;
> > > +	return 0;
> > >  }
> > > diff --git a/rdma/res-cmid.c b/rdma/res-cmid.c
> > > index bfaa47b5..3475349d 100644
> > > --- a/rdma/res-cmid.c
> > > +++ b/rdma/res-cmid.c
> > > @@ -159,8 +159,11 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
> > >  		goto out;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -199,8 +202,7 @@ static int res_cm_id_line(struct rd *rd, const char *name, int idx,
> > >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> > >  	newline(rd);
> > >  
> > > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > > +out:
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-cq.c b/rdma/res-cq.c
> > > index 9e7c4f51..5ed455ea 100644
> > > --- a/rdma/res-cq.c
> > > +++ b/rdma/res-cq.c
> > > @@ -84,8 +84,11 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
> > >  		goto out;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -123,8 +126,7 @@ static int res_cq_line(struct rd *rd, const char *name, int idx,
> > >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> > >  	newline(rd);
> > >  
> > > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > > +out:
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-ctx.c b/rdma/res-ctx.c
> > > index 30afe97a..fbd52dd5 100644
> > > --- a/rdma/res-ctx.c
> > > +++ b/rdma/res-ctx.c
> > > @@ -18,8 +18,11 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
> > >  		return MNL_CB_ERROR;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -48,8 +51,6 @@ static int res_ctx_line(struct rd *rd, const char *name, int idx,
> > >  	newline(rd);
> > >  
> > >  out:
> > > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-mr.c b/rdma/res-mr.c
> > > index 1bf73f3a..6a59d9e4 100644
> > > --- a/rdma/res-mr.c
> > > +++ b/rdma/res-mr.c
> > > @@ -47,8 +47,11 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
> > >  		goto out;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -87,8 +90,6 @@ static int res_mr_line(struct rd *rd, const char *name, int idx,
> > >  	newline(rd);
> > >  
> > >  out:
> > > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-pd.c b/rdma/res-pd.c
> > > index df538010..a51bb634 100644
> > > --- a/rdma/res-pd.c
> > > +++ b/rdma/res-pd.c
> > > @@ -34,8 +34,11 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
> > >  			nla_line[RDMA_NLDEV_ATTR_RES_UNSAFE_GLOBAL_RKEY]);
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -76,8 +79,7 @@ static int res_pd_line(struct rd *rd, const char *name, int idx,
> > >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> > >  	newline(rd);
> > >  
> > > -out:	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > > +out:
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-qp.c b/rdma/res-qp.c
> > > index a38be399..575e0529 100644
> > > --- a/rdma/res-qp.c
> > > +++ b/rdma/res-qp.c
> > > @@ -146,8 +146,11 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
> > >  		goto out;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > > @@ -179,8 +182,6 @@ static int res_qp_line(struct rd *rd, const char *name, int idx,
> > >  	print_driver_table(rd, nla_line[RDMA_NLDEV_ATTR_DRIVER]);
> > >  	newline(rd);
> > >  out:
> > > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/res-srq.c b/rdma/res-srq.c
> > > index 3038c352..945109fc 100644
> > > --- a/rdma/res-srq.c
> > > +++ b/rdma/res-srq.c
> > > @@ -174,8 +174,11 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
> > >  		return MNL_CB_ERROR;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > >  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> > > @@ -228,8 +231,6 @@ static int res_srq_line(struct rd *rd, const char *name, int idx,
> > >  	newline(rd);
> > >  
> > >  out:
> > > -	if (nla_line[RDMA_NLDEV_ATTR_RES_PID])
> > > -		free(comm);
> > >  	return MNL_CB_OK;
> > >  }
> > >  
> > > diff --git a/rdma/stat.c b/rdma/stat.c
> > > index adfcd34a..a63b70a4 100644
> > > --- a/rdma/stat.c
> > > +++ b/rdma/stat.c
> > > @@ -248,8 +248,11 @@ static int res_counter_line(struct rd *rd, const char *name, int index,
> > >  		return MNL_CB_OK;
> > >  
> > >  	if (nla_line[RDMA_NLDEV_ATTR_RES_PID]) {
> > > +		SPRINT_BUF(b);
> > > +
> > >  		pid = mnl_attr_get_u32(nla_line[RDMA_NLDEV_ATTR_RES_PID]);
> > > -		comm = get_task_name(pid);
> > > +		if (!get_task_name(pid, b))
> > > +			comm = b;
> > >  	}
> > >  	if (rd_is_filtered_attr(rd, "pid", pid,
> > >  				nla_line[RDMA_NLDEV_ATTR_RES_PID]))
> > > -- 
> > > 2.35.1
> > > 
> > 
>