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app/testpmd: fix packet burst spreading stats

PATCH Superseded Eli Britstein 2 participants 4 messages Oct 21, 2021 – Oct 22, 2021

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#0 lore raw

PATCH 1/1 app/testpmd: fix packet burst spreading stats

RX/TX functions (rte_eth_rx_burst/rte_eth_tx_burst) get 'nb_pkts' argument, which specifies the maximum number to receive/transmit. It can be 0..nb_pkts, meaning nb_pkts+1 options.
Enlarge the spread stats array by one cell to fix the possible out of range memory access.

Fixes af75078fece3 ("first public release")
---
 app/test-pmd/testpmd.c | 2 +-
 app/test-pmd/testpmd.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
app/test-pmd/testpmd.c +1 -1
index af0e79fe6d..d75451ac7b 100644
@@ -1873,7 +1873,7 @@ pkt_burst_stats_display(const char *rx_tx, struct pkt_burst_stats *pbs)
 	pktnb_stats[0] = 0;
 
 	/* Find the next 2 burst sizes with highest occurrences. */
-	for (nb_pkt = 1; nb_pkt < MAX_PKT_BURST; nb_pkt++) {
+	for (nb_pkt = 1; nb_pkt < MAX_PKT_BURST + 1; nb_pkt++) {
 		nb_burst = pbs->pkt_burst_spread[nb_pkt];
 
 		if (nb_burst == 0)
app/test-pmd/testpmd.h +1 -1
index e3995d24ab..5238308ca7 100644
@@ -96,7 +96,7 @@ enum {
  * that are recorded for each forwarding stream.
  */
 struct pkt_burst_stats {
-	unsigned int pkt_burst_spread[MAX_PKT_BURST];
+	unsigned int pkt_burst_spread[MAX_PKT_BURST + 1];
 };
 
 /** Information for a given RSS type. */
Signature · 1 line
2.28.0.2311.g225365fb51
Acked-by on v1 1/1
#1 lore raw
Quoted 6 lines · Eli Britstein

RX/TX functions (rte_eth_rx_burst/rte_eth_tx_burst) get 'nb_pkts' argument, which specifies the maximum number to receive/transmit. It can be 0..nb_pkts, meaning nb_pkts+1 options.
Enlarge the spread stats array by one cell to fix the possible out of range memory access.

This looks a valid problem, I guess problem is able to hide this long because of big MAX_PKT_BURST value in testpmd.

Can you please briefly describe what 'pkt_burst_spread[]' is in the commit log? That makes easy to understand the problem.

Quoted 5 lines
Fixes af75078fece3 ("first public release")
#2 lore raw

PATCH v2 1/1 app/testpmd: fix packet burst spreading stats

In reply to Eli Britstein

RX/TX functions (rte_eth_rx_burst/rte_eth_tx_burst) get 'nb_pkts' argument, which specifies the maximum number to receive/transmit. It can be 0..nb_pkts, meaning nb_pkts+1 options.
Testpmd can provide statistics of the burst sizes ('set record-burst-stats on') by incrementing an array cell of index <burst-size>. This array is mistakenly [MAX_PKT_BURST] size. Receiving the maximum burst will cause out of bound write.
Enlarge the spread stats array by one cell to fix it.

Fixes af75078fece3 ("first public release")
---
 app/test-pmd/testpmd.c | 2 +-
 app/test-pmd/testpmd.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
app/test-pmd/testpmd.c +1 -1
index af0e79fe6d..d75451ac7b 100644
@@ -1873,7 +1873,7 @@ pkt_burst_stats_display(const char *rx_tx, struct pkt_burst_stats *pbs)
 	pktnb_stats[0] = 0;
 
 	/* Find the next 2 burst sizes with highest occurrences. */
-	for (nb_pkt = 1; nb_pkt < MAX_PKT_BURST; nb_pkt++) {
+	for (nb_pkt = 1; nb_pkt < MAX_PKT_BURST + 1; nb_pkt++) {
 		nb_burst = pbs->pkt_burst_spread[nb_pkt];
 
 		if (nb_burst == 0)
app/test-pmd/testpmd.h +1 -1
index e3995d24ab..5238308ca7 100644
@@ -96,7 +96,7 @@ enum {
  * that are recorded for each forwarding stream.
  */
 struct pkt_burst_stats {
-	unsigned int pkt_burst_spread[MAX_PKT_BURST];
+	unsigned int pkt_burst_spread[MAX_PKT_BURST + 1];
 };
 
 /** Information for a given RSS type. */
Signature · 1 line
2.28.0.2311.g225365fb51
Applied
#3 lore raw
Quoted 9 lines · Eli Britstein

RX/TX functions (rte_eth_rx_burst/rte_eth_tx_burst) get 'nb_pkts' argument, which specifies the maximum number to receive/transmit. It can be 0..nb_pkts, meaning nb_pkts+1 options.
Testpmd can provide statistics of the burst sizes ('set record-burst-stats on') by incrementing an array cell of index <burst-size>. This array is mistakenly [MAX_PKT_BURST] size. Receiving the maximum burst will cause out of bound write.
Enlarge the spread stats array by one cell to fix it.

Quoted 6 lines
Fixes af75078fece3 ("first public release")

Applied to dpdk-next-net/main, thanks.