Messages in this thread Patch in this message | | | Date | Wed, 17 Jun 2009 19:25:59 -0400 | From | Steven Rostedt <> | Subject | [PATCH 4/7] ring-buffer: check for less than two in size allocation |
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From: Steven Rostedt <srostedt@redhat.com>
The ring buffer must have at least two pages allocated for the reader page swap to work.
The page count check will miss the case of a zero size passed in. Even though a zero size ring buffer would probably fail an allocation, making the min size check for less than two instead of equal to one makes the code a bit more robust.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/ring_buffer.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 162da23..2e99dba 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -657,8 +657,8 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags, buffer->reader_lock_key = key; /* need at least two pages */ - if (buffer->pages == 1) - buffer->pages++; + if (buffer->pages < 2) + buffer->pages = 2; /* * In case of non-hotplug cpu, if the ring-buffer is allocated -- 1.6.3.1 --
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