Re: [dpdk-dev] [PATCH v5] net/i40e: fix the core dump risk of wild pointer operation

[Ye Xiaolong <xiaolong.ye@intel.com>]

On 05/18, Wei Zhao wrote:
>In i40e PMD code of function i40e_res_pool_free(), if valid_entry
>is freed by "rte_free(valid_entry);" in the code, then the following
>code for pool update may still use the wild pointer "valid_entry"
>for pool info update. It seems has the risk of core dump for
>using wild pointer operation, we should avoid this risk.
>
>Cc: stable@dpdk.org
>Fixes: 4861cde46116 ("i40e: new poll mode driver")
>
>Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
>
>---
>
>v2:
>update commit log
>
>v3:
>set free pointer to NULL
>
>v4:
>change code style
>
>v5:
>fix an issue in v4
>---
> drivers/net/i40e/i40e_ethdev.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
>index 749d85f54..00bb05179 100644
>--- a/drivers/net/i40e/i40e_ethdev.c
>+++ b/drivers/net/i40e/i40e_ethdev.c
>@@ -4935,6 +4935,7 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
> {
> 	struct pool_entry *entry, *next, *prev, *valid_entry = NULL;
> 	uint32_t pool_offset;
>+	uint16_t len;
> 	int insert;
> 
> 	if (pool == NULL) {
>@@ -4973,12 +4974,13 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
> 	}
> 
> 	insert = 0;
>+	len = valid_entry->len;
> 	/* Try to merge with next one*/
> 	if (next != NULL) {
> 		/* Merge with next one */
>-		if (valid_entry->base + valid_entry->len == next->base) {
>+		if (valid_entry->base + len == next->base) {
> 			next->base = valid_entry->base;
>-			next->len += valid_entry->len;
>+			next->len += len;
> 			rte_free(valid_entry);
> 			valid_entry = next;
> 			insert = 1;
>@@ -4988,13 +4990,15 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
> 	if (prev != NULL) {
> 		/* Merge with previous one */
> 		if (prev->base + prev->len == valid_entry->base) {
>-			prev->len += valid_entry->len;
>+			prev->len += len;
> 			/* If it merge with next one, remove next node */
> 			if (insert == 1) {
> 				LIST_REMOVE(valid_entry, next);
> 				rte_free(valid_entry);
>+				valid_entry = NULL;
> 			} else {
> 				rte_free(valid_entry);
>+				valid_entry = NULL;
> 				insert = 1;
> 			}
> 		}
>@@ -5010,8 +5014,8 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
> 			LIST_INSERT_HEAD(&pool->free_list, valid_entry, next);
> 	}
> 
>-	pool->num_free += valid_entry->len;
>-	pool->num_alloc -= valid_entry->len;
>+	pool->num_free += len;
>+	pool->num_alloc -= len;
> 
> 	return 0;
> }
>-- 
>2.19.1
>

Reviewed-by: Xiaolong Ye <xiaolong.ye@intel.com>

Applied to dpdk-next-net-intel, Thanks.