[dpdk-dev] [PATCH] vfio: free mp_reply msgs in failure cases

[Jim Harris]

The code checks both rte_mp_request_sync() return
code and that the number of messages in the reply
equals 1.  If rte_mp_request_sync() succeeds but
there was more than one message, those messages
would get leaked.

Found via code review by Anatoly Burakov of patches
that used the vhost code as a template for using
rte_mp_request_sync().

Signed-off-by: Jim Harris <james.r.har...@intel.com>
---
 lib/librte_eal/linux/eal/eal_vfio.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/librte_eal/linux/eal/eal_vfio.c 
b/lib/librte_eal/linux/eal/eal_vfio.c
index 501c74f23..d9541b122 100644
--- a/lib/librte_eal/linux/eal/eal_vfio.c
+++ b/lib/librte_eal/linux/eal/eal_vfio.c
@@ -264,7 +264,7 @@ vfio_open_group_fd(int iommu_group_num)
        int vfio_group_fd;
        char filename[PATH_MAX];
        struct rte_mp_msg mp_req, *mp_rep;
-       struct rte_mp_reply mp_reply;
+       struct rte_mp_reply mp_reply = {0};
        struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
        struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
 
@@ -320,9 +320,9 @@ vfio_open_group_fd(int iommu_group_num)
                        RTE_LOG(ERR, EAL, "  bad VFIO group fd\n");
                        vfio_group_fd = 0;
                }
-               free(mp_reply.msgs);
        }
 
+       free(mp_reply.msgs);
        if (vfio_group_fd < 0)
                RTE_LOG(ERR, EAL, "  cannot request group fd\n");
        return vfio_group_fd;
@@ -554,7 +554,7 @@ static int
 vfio_sync_default_container(void)
 {
        struct rte_mp_msg mp_req, *mp_rep;
-       struct rte_mp_reply mp_reply;
+       struct rte_mp_reply mp_reply = {0};
        struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
        struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
        int iommu_type_id;
@@ -584,8 +584,8 @@ vfio_sync_default_container(void)
                p = (struct vfio_mp_param *)mp_rep->param;
                if (p->result == SOCKET_OK)
                        iommu_type_id = p->iommu_type_id;
-               free(mp_reply.msgs);
        }
+       free(mp_reply.msgs);
        if (iommu_type_id < 0) {
                RTE_LOG(ERR, EAL, "Could not get IOMMU type for default 
container\n");
                return -1;
@@ -1021,7 +1021,7 @@ int
 vfio_get_default_container_fd(void)
 {
        struct rte_mp_msg mp_req, *mp_rep;
-       struct rte_mp_reply mp_reply;
+       struct rte_mp_reply mp_reply = {0};
        struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
        struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
 
@@ -1049,9 +1049,9 @@ vfio_get_default_container_fd(void)
                        free(mp_reply.msgs);
                        return mp_rep->fds[0];
                }
-               free(mp_reply.msgs);
        }
 
+       free(mp_reply.msgs);
        RTE_LOG(ERR, EAL, "  cannot request default container fd\n");
        return -1;
 }
@@ -1127,7 +1127,7 @@ rte_vfio_get_container_fd(void)
 {
        int ret, vfio_container_fd;
        struct rte_mp_msg mp_req, *mp_rep;
-       struct rte_mp_reply mp_reply;
+       struct rte_mp_reply mp_reply = {0};
        struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
        struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
 
@@ -1181,9 +1181,9 @@ rte_vfio_get_container_fd(void)
                        free(mp_reply.msgs);
                        return vfio_container_fd;
                }
-               free(mp_reply.msgs);
        }
 
+       free(mp_reply.msgs);
        RTE_LOG(ERR, EAL, "  cannot request container fd\n");
        return -1;
 }