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axeld + bonefish:

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Changed condition variables so that it is allowed to block (e.g. lock
mutexes etc.) between Add() and Wait(). This fixes #2059, since the
block writer used them this way and could thusly fail to wait for a
condition variable, causing a temporary stack object to be used past its
lifetime.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25525 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Ingo Weinhold
2008-05-17 10:21:37 +00:00
parent a93840a2f4
commit fbe0c27a94
5 changed files with 43 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/system/kernel/condition_variable.cpp
+32 -13
View File
@@ -17,6 +17,10 @@
#include <util/AutoLock.h>
#define STATUS_ADDED 1
#define STATUS_WAITING 2
static const int kConditionVariableHashSize = 512;
@@ -90,7 +94,7 @@ dump_condition_variable(int argc, char** argv)
bool
ConditionVariableEntry::Add(const void* object, uint32 flags)
ConditionVariableEntry::Add(const void* object)
{
ASSERT(object != NULL);
@@ -100,16 +104,12 @@ ConditionVariableEntry::Add(const void* object, uint32 flags)
fVariable = sConditionVariableHash.Lookup(object);
thread_prepare_to_block(fThread, flags,
THREAD_BLOCK_TYPE_CONDITION_VARIABLE, fVariable);
if (fVariable == NULL) {
SpinLocker threadLocker(thread_spinlock);
thread_unblock_locked(fThread, B_ENTRY_NOT_FOUND);
fWaitStatus = B_ENTRY_NOT_FOUND;
return false;
}
// add to the queue for the variable
fWaitStatus = STATUS_ADDED;
fVariable->fEntries.Add(this);
return true;
@@ -117,7 +117,7 @@ ConditionVariableEntry::Add(const void* object, uint32 flags)
status_t
ConditionVariableEntry::Wait(uint32 timeoutFlags, bigtime_t timeout)
ConditionVariableEntry::Wait(uint32 flags, bigtime_t timeout)
{
if (!are_interrupts_enabled()) {
panic("wait_for_condition_variable_entry() called with interrupts "
@@ -127,15 +127,28 @@ ConditionVariableEntry::Wait(uint32 timeoutFlags, bigtime_t timeout)
InterruptsLocker _;
SpinLocker conditionLocker(sConditionVariablesLock);
if (fVariable == NULL)
return fWaitStatus;
thread_prepare_to_block(fThread, flags,
THREAD_BLOCK_TYPE_CONDITION_VARIABLE, fVariable);
fWaitStatus = STATUS_WAITING;
conditionLocker.Unlock();
SpinLocker threadLocker(thread_spinlock);
status_t error;
if ((timeoutFlags & (B_RELATIVE_TIMEOUT | B_ABSOLUTE_TIMEOUT)) != 0)
error = thread_block_with_timeout_locked(timeoutFlags, timeout);
if ((flags & (B_RELATIVE_TIMEOUT | B_ABSOLUTE_TIMEOUT)) != 0)
error = thread_block_with_timeout_locked(flags, timeout);
else
error = thread_block_locked(thread_get_current_thread());
threadLocker.Unlock();
SpinLocker locker(sConditionVariablesLock);
conditionLocker.Lock();
// remove entry from variable, if not done yet
if (fVariable != NULL) {
@@ -151,7 +164,7 @@ status_t
ConditionVariableEntry::Wait(const void* object, uint32 flags,
bigtime_t timeout)
{
if (Add(object, flags))
if (Add(object))
return Wait(flags, timeout);
return B_ENTRY_NOT_FOUND;
}
@@ -294,7 +307,13 @@ ConditionVariable::_NotifyChecked(bool all, status_t result)
while (ConditionVariableEntry* entry = fEntries.RemoveHead()) {
entry->fVariable = NULL;
thread_unblock_locked(entry->fThread, B_OK);
if (entry->fWaitStatus <= 0)
continue;
if (entry->fWaitStatus == STATUS_WAITING)
thread_unblock_locked(entry->fThread, result);
entry->fWaitStatus = result;
if (!all)
break;