static bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
{
- enum kcov_mode mode;
+ unsigned int mode;
/*
* We are interested in code coverage as a function of a syscall inputs,
void kcov_task_init(struct task_struct *t)
{
- t->kcov_mode = KCOV_MODE_DISABLED;
+ WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
+ barrier();
t->kcov_size = 0;
t->kcov_area = NULL;
t->kcov = NULL;
return 0;
}
+/*
+ * Fault in a lazily-faulted vmalloc area before it can be used by
+ * __santizer_cov_trace_pc(), to avoid recursion issues if any code on the
+ * vmalloc fault handling path is instrumented.
+ */
+static void kcov_fault_in_area(struct kcov *kcov)
+{
+ unsigned long stride = PAGE_SIZE / sizeof(unsigned long);
+ unsigned long *area = kcov->area;
+ unsigned long offset;
+
+ for (offset = 0; offset < kcov->size; offset += stride)
+ READ_ONCE(area[offset]);
+}
+
static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
unsigned long arg)
{
*/
if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
return -EINVAL;
- if (kcov->t != NULL)
+ t = current;
+ if (kcov->t != NULL || t->kcov != NULL)
return -EBUSY;
if (arg == KCOV_TRACE_PC)
kcov->mode = KCOV_MODE_TRACE_PC;
#endif
else
return -EINVAL;
- t = current;
+ kcov_fault_in_area(kcov);
/* Cache in task struct for performance. */
t->kcov_size = kcov->size;
t->kcov_area = kcov->area;