diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2010-01-26 16:14:08 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2010-01-26 16:14:08 -0500 |
| commit | 3c05d7482777f15e71bb4cb1ba78dee2800dfec6 (patch) | |
| tree | cb3d7c935ede863ca94e0beb97dc57ceb1e75e7b | |
| parent | 492a74f4210e15f4701422e2e1c4cd3c1e45ddae (diff) | |
| download | linux-next-3c05d7482777f15e71bb4cb1ba78dee2800dfec6.tar.gz | |
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: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 503b630e0bda..8c1b2d290718 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3064,9 +3064,6 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_event *event; int nr_loops = 0; - if (ring_buffer_iter_empty(iter)) - return NULL; - cpu_buffer = iter->cpu_buffer; buffer = cpu_buffer->buffer; @@ -3080,6 +3077,9 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) rb_iter_reset(iter); again: + if (ring_buffer_iter_empty(iter)) + return NULL; + /* * We repeat when a timestamp is encountered. * 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)) return NULL; + if (iter->head >= local_read(&iter->head_page->page->commit)) { + rb_inc_iter(iter); + goto again; + } + event = rb_iter_head_event(iter); switch (event->type_len) { |