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)
{
#endif
else
return -EINVAL;
+ kcov_fault_in_area(kcov);
/* Cache in task struct for performance. */
t->kcov_size = kcov->size;
t->kcov_area = kcov->area;