Team2890/allwpilib
4
0
Fork 0
mirror of https://github.com/wpilibsuite/allwpilib synced 2026-06-27 02:01:42 +00:00
Code Issues Packages Projects Releases Wiki Activity

Adds a static mutex to notifiers to stop destructor race condition (#204)

Browse Source
This commit is contained in:
Thad House
2016-08-15 19:56:32 -07:00
committed by Peter Johnson
parent 776cb915bc
commit 40365faeda
7 changed files with 49 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
wpilibc/athena/src/Notifier.cpp
View File

@@ -11,6 +11,8 @@
#include "Utility.h"
#include "WPIErrors.h"
priority_mutex Notifier::m_destructorMutex;
/**
* Create a Notifier for timer event notification.
*
@@ -39,7 +41,8 @@ Notifier::~Notifier() {
/* Acquire the mutex; this makes certain that the handler is not being
* executed by the interrupt manager.
*/
std::lock_guard<priority_mutex> lock(m_notifyMutex);
std::lock_guard<priority_mutex> lockStatic(Notifier::m_destructorMutex);
std::lock_guard<priority_mutex> lock(m_processMutex);
}
/**
@@ -47,6 +50,8 @@ Notifier::~Notifier() {
*/
void Notifier::UpdateAlarm() {
int32_t status = 0;
// Return if we are being destructed, or were not created successfully
if (m_notifier == 0) return;
HAL_UpdateNotifierAlarm(
m_notifier, static_cast<uint64_t>(m_expirationTime * 1e6), &status);
wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
@@ -56,10 +61,18 @@ void Notifier::UpdateAlarm() {
* Notify is called by the HAL layer. We simply need to pass it through to
* the user handler.
*/
void Notifier::Notify(uint64_t currentTimeInt, void* param) {
Notifier* notifier = static_cast<Notifier*>(param);
void Notifier::Notify(uint64_t currentTimeInt, HAL_NotifierHandle handle) {
Notifier* notifier;
{
// Lock static mutex to grab the notifier param
std::lock_guard<priority_mutex> lock(Notifier::m_destructorMutex);
int32_t status = 0;
auto notifierPointer = HAL_GetNotifierParam(handle, &status);
if (notifierPointer == nullptr) return;
notifier = static_cast<Notifier*>(notifierPointer);
notifier->m_processMutex.lock();
}
notifier->m_processMutex.lock();
if (notifier->m_periodic) {
notifier->m_expirationTime += notifier->m_period;
notifier->UpdateAlarm();
@@ -67,11 +80,8 @@ void Notifier::Notify(uint64_t currentTimeInt, void* param) {
auto handler = notifier->m_handler;
notifier->m_notifyMutex.lock();
notifier->m_processMutex.unlock();
if (handler) handler();
notifier->m_notifyMutex.unlock();
notifier->m_processMutex.unlock();
}
/**
@@ -123,5 +133,6 @@ void Notifier::Stop() {
// Wait for a currently executing handler to complete before returning from
// Stop()
std::lock_guard<priority_mutex> sync(m_notifyMutex);
std::lock_guard<priority_mutex> lockStatic(Notifier::m_destructorMutex);
std::lock_guard<priority_mutex> lock(m_processMutex);
}