kernel: make kcov_common_handle consider the current context

kcov_common_handle is a method that is used to obtain a "default" KCOV remote handle of the current process. The handle can later be passed to kcov_remote_start in order to collect coverage for the processing that is initiated by one process, but done in another. For details see Documentation/dev-tools/kcov.rst and comments in kernel/kcov.c. Presently, if kcov_common_handle is called in an IRQ context, it will return a handle for the interrupted process. This may lead to unreliable and incorrect coverage collection. Adjust the behavior of kcov_common_handle in the following way. If it is called in a task context, return the common handle for the currently running task. Otherwise, return 0. Signed-off-by: Aleksandr Nogikh <[email protected]> Reviewed-by: Andrey Konovalov <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
mrcsosa · Nov 3, 2020 · b08e84d · b08e84d
1 parent 0e8c266
commit b08e84d
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/kernel/kcov.c b/kernel/kcov.c
@@ -1023,6 +1023,8 @@ EXPORT_SYMBOL(kcov_remote_stop);
 /* See the comment before kcov_remote_start() for usage details. */
 u64 kcov_common_handle(void)
 {
+	if (!in_task())
+		return 0;
 	return current->kcov_handle;
 }
 EXPORT_SYMBOL(kcov_common_handle);