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Atomic test: Fix use after free 

SDL_SemPost() was called by the FIFO threads after the semaphore was
freed because the main thread actually synchronized on the
`writerRunning`/`readersRunning` count and not the semaphores itself.
This commit is contained in:
Joel Linn 2020-12-23 13:36:23 -08:00
parent 6267b95177
commit 2b040cebbe
1 changed files with 2 additions and 8 deletions
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10
test/testatomic.c
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@ -473,8 +473,6 @@ static SDL_bool DequeueEvent_Mutex(SDL_EventQueue *queue, SDL_Event *event)
static SDL_sem *writersDone;
static SDL_sem *readersDone;
static SDL_atomic_t writersRunning;
static SDL_atomic_t readersRunning;
typedef struct
{
@ -525,7 +523,6 @@ static int SDLCALL FIFO_Writer(void* _data)
}
}
}
SDL_AtomicAdd(&writersRunning, -1);
SDL_SemPost(writersDone);
return 0;
}
@ -563,7 +560,6 @@ static int SDLCALL FIFO_Reader(void* _data)
}
}
}
SDL_AtomicAdd(&readersRunning, -1);
SDL_SemPost(readersDone);
return 0;
}
@ -627,7 +623,6 @@ static void RunFIFOTest(SDL_bool lock_free)
/* Start the readers first */
SDL_Log("Starting %d readers\n", NUM_READERS);
SDL_zeroa(readerData);
SDL_AtomicSet(&readersRunning, NUM_READERS);
for (i = 0; i < NUM_READERS; ++i) {
char name[64];
SDL_snprintf(name, sizeof (name), "FIFOReader%d", i);
@ -639,7 +634,6 @@ static void RunFIFOTest(SDL_bool lock_free)
/* Start up the writers */
SDL_Log("Starting %d writers\n", NUM_WRITERS);
SDL_zeroa(writerData);
SDL_AtomicSet(&writersRunning, NUM_WRITERS);
for (i = 0; i < NUM_WRITERS; ++i) {
char name[64];
SDL_snprintf(name, sizeof (name), "FIFOWriter%d", i);
@ -650,7 +644,7 @@ static void RunFIFOTest(SDL_bool lock_free)
}
/* Wait for the writers */
while (SDL_AtomicGet(&writersRunning) > 0) {
for (i = 0; i < NUM_WRITERS; ++i) {
SDL_SemWait(writersDone);
}
@ -658,7 +652,7 @@ static void RunFIFOTest(SDL_bool lock_free)
SDL_AtomicSet(&queue.active, 0);
/* Wait for the readers */
while (SDL_AtomicGet(&readersRunning) > 0) {
for (i = 0; i < NUM_READERS; ++i) {
SDL_SemWait(readersDone);
}