diff options
| -rw-r--r-- | kernel/kcov.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c index 5be9a60a959f..cf250392c55c 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -324,6 +324,21 @@ static int kcov_close(struct inode *inode, struct file *filep) 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) { @@ -372,6 +387,7 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, #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; |