From: Oliver Kurth <okurth@vmware.com>
Date: Fri, 26 Oct 2018 17:44:57 +0000 (-0700)
Subject: Handle Linux kernel /proc FS uint32 type stat overflow when calculating tools rate... 
X-Git-Tag: stable-11.0.0~376
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=45f0733b4eeb4b46f820a5db911917cfbb769d37;p=thirdparty%2Fopen-vm-tools.git

Handle Linux kernel /proc FS uint32 type stat overflow when calculating tools rate stats.

On both 32-bit and 64-bit Linux, tools always parses Linux kernel /proc FS
stats as uint64 values. For rate stats, current - previous can handle uint64
type stat overflow, but not uint32 type.
---

diff --git a/open-vm-tools/services/plugins/guestInfo/perfMonLinux.c b/open-vm-tools/services/plugins/guestInfo/perfMonLinux.c
index fa2344b0f..eb74faa55 100644
--- a/open-vm-tools/services/plugins/guestInfo/perfMonLinux.c
+++ b/open-vm-tools/services/plugins/guestInfo/perfMonLinux.c
@@ -1094,7 +1094,18 @@ GuestInfoAppendRate(Bool emitNameSpace,             // IN:
       if (reportID == GuestStatID_Linux_DiskRequestQueueAvg) {
          valueDelta = ((double)(currentStat->value)) / 10;
       } else {
-         valueDelta = currentStat->value - previousStat->value;
+         /*
+          * The /proc FS stat can be uint32 type in the kernel on both x86
+          * and x64 Linux, it is parsed and stored as uint64 in tools, so we
+          * also need to handle uint32 overflow here.
+          */
+         if (currentStat->value < previousStat->value &&
+             previousStat->value <= MAX_UINT32) {
+            valueDelta = (uint32)(currentStat->value) -
+                         (uint32)(previousStat->value);
+         } else {
+            valueDelta = currentStat->value - previousStat->value;
+         }
       }
 
       valueDouble = valueDelta / timeDelta;