On Tue, Jan 09, 2018 at 08:29:28AM -0600, Keith Wiles wrote:
> The rte_pktmbuf_free() allows for NULL mbuf pointer, but
> when sanity check is enabled it will panic with null pointer.
>
> Signed-off-by: Keith Wiles <keith.wi...@intel.com>
> ---
> lib/librte_mbuf/rte_mbuf.c | 10 ++++++++--
> test/test/test_mbuf.c | 4 +---
> 2 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 7543662f7..621679c92 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -205,8 +205,9 @@ rte_mbuf_sanity_check(const struct rte_mbuf *m, int
> is_header)
> const struct rte_mbuf *m_seg;
> unsigned int nb_segs;
>
> - if (m == NULL)
> - rte_panic("mbuf is NULL\n");
> + /* Calling with NULL is valid in the API */
> + if (!m)
> + return;
>
> /* generic checks */
> if (m->pool == NULL)
> @@ -243,6 +244,11 @@ rte_pktmbuf_dump(FILE *f, const struct rte_mbuf *m,
> unsigned dump_len)
>
> __rte_mbuf_sanity_check(m, 1);
>
> + if (!m) {
> + fprintf(stderr, "MBUF pointer is NULL\n");
> + return;
> + }
> +
> fprintf(f, "dump mbuf at %p, iova=%"PRIx64", buf_len=%u\n",
> m, (uint64_t)m->buf_iova, (unsigned)m->buf_len);
> fprintf(f, " pkt_len=%"PRIu32", ol_flags=%"PRIx64", nb_segs=%u, "
> diff --git a/test/test/test_mbuf.c b/test/test/test_mbuf.c
> index 9e82a20be..146eaf0e5 100644
> --- a/test/test/test_mbuf.c
> +++ b/test/test/test_mbuf.c
> @@ -864,10 +864,8 @@ test_failing_mbuf_sanity_check(struct rte_mempool
> *pktmbuf_pool)
>
> printf("Now checking for error conditions\n");
>
> - if (verify_mbuf_check_panics(NULL)) {
> - printf("Error with NULL mbuf test\n");
> + if (verify_mbuf_check_panics(NULL) != -1)
> return -1;
> - }
>
> badbuf = *buf;
> badbuf.pool = NULL;
> --
> 2.14.1
>
The problem is a panic when rte_pktmbuf_free(NULL) when mbuf debug is enabled,
right?
A NULL mbuf is only valid in case of a free because it is convenient, but for
most (all ?) other mbuf functions, the mbuf must not be NULL.
What about this patch instead:
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1413,13 +1413,14 @@ rte_pktmbuf_free_seg(struct rte_mbuf *m)
* segment is added back into its original mempool.
*
* @param m
- * The packet mbuf to be freed.
+ * The packet mbuf to be freed. If NULL, the function does nothing.
*/
static inline void rte_pktmbuf_free(struct rte_mbuf *m)
{
struct rte_mbuf *m_next;
- __rte_mbuf_sanity_check(m, 1);
+ if (m != NULL)
+ __rte_mbuf_sanity_check(m, 1);
while (m != NULL) {
m_next = m->next;
