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Commit 3c05d748 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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ring-buffer: Check for end of page in iterator 



If the iterator comes to an empty page for some reason, or if
the page is emptied by a consuming read. The iterator code currently
does not check if the iterator is pass the contents, and may
return a false entry.

This patch adds a check to the ring buffer iterator to test if the
current page has been completely read and sets the iterator to the
next page if necessary.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 492a74f4

kernel/trace/ring_buffer.c

+8 −3
Original line number Original line Diff line number Diff line
@@ -3064,9 +3064,6 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) 
	struct ring_buffer_event *event;

	struct ring_buffer_event *event;

	int nr_loops = 0;

	int nr_loops = 0;





	if (ring_buffer_iter_empty(iter))

		return NULL;



	cpu_buffer = iter->cpu_buffer;

	cpu_buffer = iter->cpu_buffer;

	buffer = cpu_buffer->buffer;

	buffer = cpu_buffer->buffer;
@@ -3080,6 +3077,9 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) 
		rb_iter_reset(iter);

		rb_iter_reset(iter);





 again:

 again:

	if (ring_buffer_iter_empty(iter))

		return NULL;



	/*

	/*

	 * We repeat when a timestamp is encountered.

	 * We repeat when a timestamp is encountered.

	 * We can get multiple timestamps by nested interrupts or also

	 * We can get multiple timestamps by nested interrupts or also
@@ -3094,6 +3094,11 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) 
	if (rb_per_cpu_empty(cpu_buffer))

	if (rb_per_cpu_empty(cpu_buffer))

		return NULL;

		return NULL;





	if (iter->head >= local_read(&iter->head_page->page->commit)) {

		rb_inc_iter(iter);

		goto again;

	}



	event = rb_iter_head_event(iter);

	event = rb_iter_head_event(iter);





	switch (event->type_len) {

	switch (event->type_len) {