Skip to content
This repository was archived by the owner on Sep 8, 2020. It is now read-only.

Fix a case where the usertime calculation can overflow (see issue #202) #298

Merged
hishamhm merged 1 commit into from
Oct 26, 2015
Merged

Fix a case where the usertime calculation can overflow (see issue #202) #298

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 7 additions & 5 deletions linux/LinuxProcessList.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -695,8 +695,6 @@ static inline double LinuxProcessList_scanCPUTime(LinuxProcessList* this) {
unsigned long long int virtalltime = guest + guestnice;
unsigned long long int totaltime = usertime + nicetime + systemalltime + idlealltime + steal + virtalltime;
CPUData* cpuData = &(this->cpus[i]);
assert (usertime >= cpuData->userTime);
assert (nicetime >= cpuData->niceTime);
assert (systemtime >= cpuData->systemTime);
assert (idletime >= cpuData->idleTime);
assert (totaltime >= cpuData->totalTime);
Expand All @@ -707,8 +705,11 @@ static inline double LinuxProcessList_scanCPUTime(LinuxProcessList* this) {
assert (softIrq >= cpuData->softIrqTime);
assert (steal >= cpuData->stealTime);
assert (virtalltime >= cpuData->guestTime);
cpuData->userPeriod = usertime - cpuData->userTime;
cpuData->nicePeriod = nicetime - cpuData->niceTime;
// Since we do a subtraction (usertime - guest) and cputime64_to_clock_t()
// used in /proc/stat rounds down numbers, it can lead to a case where the
// integer overflow.
cpuData->userPeriod = (usertime > cpuData->userTime) ? usertime - cpuData->userTime : 0;
cpuData->nicePeriod = (nicetime > cpuData->niceTime) ? nicetime - cpuData->niceTime : 0;
cpuData->systemPeriod = systemtime - cpuData->systemTime;
cpuData->systemAllPeriod = systemalltime - cpuData->systemAllTime;
cpuData->idleAllPeriod = idlealltime - cpuData->idleAllTime;
Expand All @@ -732,7 +733,8 @@ static inline double LinuxProcessList_scanCPUTime(LinuxProcessList* this) {
cpuData->guestTime = virtalltime;
cpuData->totalTime = totaltime;
}
double period = (double)this->cpus[0].totalPeriod / cpus; fclose(file);
double period = (double)this->cpus[0].totalPeriod / cpus;
fclose(file);
return period;
}

Expand Down