kcov: use t->kcov_mode as enabled indicator (5fe7042d) · Commits · 戴 / test

Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find out whether the coverage is already being collected by the current task. Use t->kcov_mode for that instead. This doesn't change the overall behavior in any way, but serves as a preparation for the following softirq coverage collection support patch. Signed-off-by:

Andrey Konovalov <andreyknvl@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Reviewed-by:

Dmitry Vyukov <dvyukov@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Potapenko <glider@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Link: http://lkml.kernel.org/r/f70377945d1d8e6e4916cbce871a12303d6186b4.1585233617.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/ee1a1dec43059da5d7664c85c1addc89c4cd58de.1584655448.git.andreyknvl@google.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/kcov.c

+23 −9

Original line number	Diff line number	Diff line
		@@ -746,26 +746,33 @@ static const struct file_operations kcov_fops = {
		* In turns kcov_remote_stop() clears those pointers from task_struct to stop
		* collecting coverage and copies all collected coverage into the kcov area.
		*/

		static inline bool kcov_mode_enabled(unsigned int mode)
		{
		return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED;
		}

		void kcov_remote_start(u64 handle)
		{
		struct task_struct *t = current;
		struct kcov_remote *remote;
		struct kcov *kcov;
		unsigned int mode;
		void *area;
		struct task_struct *t;
		unsigned int size;
		enum kcov_mode mode;
		int sequence;

		if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
		return;
		if (WARN_ON(!in_task()))
		return;
		t = current;

		/*
		* Check that kcov_remote_start is not called twice
		* nor called by user tasks (with enabled kcov).
		*/
		if (WARN_ON(t->kcov))
		mode = READ_ONCE(t->kcov_mode);
		if (WARN_ON(kcov_mode_enabled(mode)))
		return;

		kcov_debug("handle = %llx\n", handle);
		@@ -863,13 +870,20 @@ static void kcov_move_area(enum kcov_mode mode, void *dst_area,
		void kcov_remote_stop(void)
		{
		struct task_struct *t = current;
		struct kcov *kcov = t->kcov;
		void *area = t->kcov_area;
		unsigned int size = t->kcov_size;
		int sequence = t->kcov_sequence;
		struct kcov *kcov;
		unsigned int mode;
		void *area;
		unsigned int size;
		int sequence;

		if (!kcov)
		mode = READ_ONCE(t->kcov_mode);
		barrier();
		if (!kcov_mode_enabled(mode))
		return;
		kcov = t->kcov;
		area = t->kcov_area;
		size = t->kcov_size;
		sequence = t->kcov_sequence;

		kcov_stop(t);

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