[dpdk-stable] patch 'examples/power: fix overflowed value' has been queued to LTS release 18.11.2

[Kevin Traynor]

Hi,

FYI, your patch has been queued to LTS release 18.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/13/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable-queue/commit/ef24b4826f540c0489aadd2c84d9c22e2510a014

Thanks.

Kevin Traynor

---
>From ef24b4826f540c0489aadd2c84d9c22e2510a014 Mon Sep 17 00:00:00 2001
From: Reshma Pattan <reshma.pattan at intel.com>
Date: Thu, 11 Apr 2019 12:13:36 +0100
Subject: [PATCH] examples/power: fix overflowed value

[ upstream commit 7e7b7a1f427013374f38e1b101969a1dbce5c9c1 ]

Fix the data type of last_branches, last_branch_misses
from uint32_t to uint64_t, and for hits_diff, miss_diff
from int to int64_t respectively to fix possible
overflow or truncation.

Coverity issue: 337677
Fixes: 4b1a631b8a ("examples/vm_power: add oob monitoring functions")

Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 examples/vm_power_manager/oob_monitor_x86.c | 23 ++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/examples/vm_power_manager/oob_monitor_x86.c b/examples/vm_power_manager/oob_monitor_x86.c
index 589c604e5..ebd96b205 100644
--- a/examples/vm_power_manager/oob_monitor_x86.c
+++ b/examples/vm_power_manager/oob_monitor_x86.c
@@ -34,8 +34,8 @@ apply_policy(int core)
 {
 	struct core_info *ci;
-	uint64_t counter;
+	uint64_t counter = 0;
 	uint64_t branches, branch_misses;
-	uint32_t last_branches, last_branch_misses;
-	int hits_diff, miss_diff;
+	uint64_t last_branches, last_branch_misses;
+	int64_t hits_diff, miss_diff;
 	float ratio;
 	int ret;
@@ -55,4 +55,5 @@ apply_policy(int core)
 	branches = counter;
 
+	counter = 0;
 	ret = pread(ci->cd[core].msr_fd, &counter,
 			sizeof(counter), IA32_PERFCTR1);
@@ -67,5 +68,11 @@ apply_policy(int core)
 	ci->cd[core].last_branch_misses = branch_misses;
 
-	hits_diff = (int)branches - (int)last_branches;
+	/*
+	 * Intentional right shift to make MSB 0 to avoid
+	 * possible signed overflow or truncation.
+	 */
+	branches >>= 1;
+	last_branches >>= 1;
+	hits_diff = (int64_t)branches - (int64_t)last_branches;
 	if (hits_diff <= 0) {
 		/* Likely a counter overflow condition, skip this round */
@@ -73,5 +80,11 @@ apply_policy(int core)
 	}
 
-	miss_diff = (int)branch_misses - (int)last_branch_misses;
+	/*
+	 * Intentional right shift to make MSB 0 to avoid
+	 * possible signed overflow or truncation.
+	 */
+	branch_misses >>= 1;
+	last_branch_misses >>= 1;
+	miss_diff = (int64_t)branch_misses - (int64_t)last_branch_misses;
 	if (miss_diff <= 0) {
 		/* Likely a counter overflow condition, skip this round */
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-05-08 11:05:07.473473845 +0100
+++ 0033-examples-power-fix-overflowed-value.patch	2019-05-08 11:05:05.815933054 +0100
@@ -1 +1 @@
-From 7e7b7a1f427013374f38e1b101969a1dbce5c9c1 Mon Sep 17 00:00:00 2001
+From ef24b4826f540c0489aadd2c84d9c22e2510a014 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 7e7b7a1f427013374f38e1b101969a1dbce5c9c1 ]
+
@@ -13 +14,0 @@
-Cc: stable at dpdk.org