Commit b08e84da authored Oct 29, 2020 by Aleksandr Nogikh Committed by Jakub Kicinski Nov 02, 2020

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 <nogikh@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 0e8c266c

kernel/kcov.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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);

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