Issue |
122758
|
Summary |
Thread-safety analysis produces incorrect results for cleanup functions
|
Labels |
new issue
|
Assignees |
|
Reporter |
bvanassche
|
Building the following code with `-Wthread-safety` produces compiler warnings while no warnings should be reported:
```
#include <stdio.h>
struct __attribute__((capability("mutex"))) mutex {
};
static void mutex_lock(struct mutex *m)
__attribute__((exclusive_lock_function(*m)))
__attribute__((no_thread_safety_analysis))
{
puts(__func__);
}
static void mutex_unlock(struct mutex *m)
__attribute__((unlock_function(*m)))
__attribute__((no_thread_safety_analysis))
{
puts(__func__);
}
static void mutex_cleanup(struct mutex **m)
__attribute__((unlock_function(**m)))
{
puts(__func__);
mutex_unlock(*m);
}
int main(void)
{
struct mutex m = {};
mutex_lock(&m);
#if 1
struct mutex *m_ptr __attribute__((cleanup(mutex_cleanup))) = &m;
#else
mutex_unlock(&m);
#endif
return 0;
}
```
The following compiler warnings are reported:
```
annotated-cleanup.c:32:19: warning: releasing mutex 'm_ptr' that was not held [-Wthread-safety-analysis]
32 | struct mutex *m_ptr __attribute__((cleanup(mutex_cleanup))) = &m;
| ^
annotated-cleanup.c:37:1: warning: mutex 'm' is still held at the end of function [-Wthread-safety-analysis]
37 | }
| ^
annotated-cleanup.c:30:5: note: mutex acquired here
30 | mutex_lock(&m);
| ^
2 warnings generated.
```
The program output shows that both the lock and unlock functions are called:
```
mutex_lock
mutex_cleanup
mutex_unlock
```
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