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SubjectRe: [PATCH 3/3] tracing: Check cpu file on tracing_release()
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On Wed, 2013-04-10 at 09:18 +0900, Namhyung Kim wrote:
> From: Namhyung Kim <namhyung.kim@lge.com>
>
> It looks like tracing_release() lacks checking iter->cpu_file so that
> closing a per_cpu trace file would attempt to close all cpu buffers.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
> kernel/trace/trace.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 7270460cfe3c..0beddcb80509 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -2883,7 +2883,13 @@ static int tracing_release(struct inode *inode, struct file *file)
> WARN_ON(!tr->ref);
> tr->ref--;
>
> - for_each_tracing_cpu(cpu) {
> + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
> + for_each_tracing_cpu(cpu) {
> + if (iter->buffer_iter[cpu])

Only the cpu that is assigned gets buffer_iter[cpu] set. The other
buffer_iter[cpus] will simply be ignored.

-- Steve

> + ring_buffer_read_finish(iter->buffer_iter[cpu]);
> + }
> + } else {
> + cpu = iter->cpu_file;
> if (iter->buffer_iter[cpu])
> ring_buffer_read_finish(iter->buffer_iter[cpu]);
> }




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