Re: [dpdk-dev] [PATCH 5/5] malloc: fix potential negative return

[Tan, Jianfeng]

On 4/17/2018 11:48 PM, Anatoly Burakov wrote:
Return value from rte_socket_id_by_idx() may be negative, which would
result in negative index access.

Additionally, return value was of mismatched type (function returns
signed int, socket id was unsigned).

Coverity issue: 272571
Coverity issue: 272597

Fixes: 30bc6bf0d516 ("malloc: add function to dump heap contents")
Cc: anatoly.bura...@intel.com

Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
  lib/librte_eal/common/rte_malloc.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/rte_malloc.c 
b/lib/librte_eal/common/rte_malloc.c
index b51a6d1..f207ba2 100644
--- a/lib/librte_eal/common/rte_malloc.c
+++ b/lib/librte_eal/common/rte_malloc.c
@@ -169,7 +169,11 @@ rte_malloc_dump_heaps(FILE *f)
        unsigned int idx;
  
  	for (idx = 0; idx < rte_socket_count(); idx++) {
-               unsigned int socket = rte_socket_id_by_idx(idx);
+               int socket = rte_socket_id_by_idx(idx);
+               if (socket < 0) {
+                       RTE_LOG(ERR, EAL, "Invalid socket index: %u\n", idx);
+                       continue;
+               }

For such check (and many others), we are clear that idx is guaranteed by 
rte_socket_count(), so rte_socket_id_by_idx() can never return -1. So 
why not just reporting this as false-positive?

Thanks,
Jianfeng

                fprintf(f, "Heap on socket %i:\n", socket);
                malloc_heap_dump(&mcfg->malloc_heaps[socket], f);
        }