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Date: Fri, 8 Nov 2013 10:34:55 +0100
From: Jiri Olsa <jolsa@redhat.com>
To: David Ahern <dsahern@gmail.com>
Cc: acme@ghostprotocols.net, linux-kernel@vger.kernel.org, mingo@kernel.org,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Namhyung Kim <namhyung@kernel.org>, Mike Galbraith <efault@gmx.de>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 2/2] perf record: mmap output file - v4
Message-ID: <20131108093455.GA1230@krava.brq.redhat.com>
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On Thu, Nov 07, 2013 at 09:23:25PM -0700, David Ahern wrote:

SNIP

>  
> +static void mmap_output_fini(struct perf_record *rec)
> +{
> +	off_t len;
> +	int fd;
> +
> +	if (!rec->mmap.use)
> +		return;
> +
> +	rec->mmap.use = false;
> +
> +	len = rec->session->header.data_offset + rec->bytes_written;
> +	fd = rec->file.fd;
> +
> +	munmap(rec->mmap.addr, rec->mmap.out_size);
> +	rec->mmap.addr = NULL;
> +
> +	if (ftruncate(fd, len) != 0)
> +		pr_err("ftruncate failed\n");

I think we should fail here and dont let the finishing
code run on probably corrupted file.

the code that process build IDs could even get stuck

jirka