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Date: Fri, 12 Jan 2018 16:46:28 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
        lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        David Ahern <dsahern@gmail.com>,
        Andi Kleen <ak@linux.intel.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>
Subject: Re: [PATCH] perf tools: Fix copyfile_offset update of output offset
Message-ID: <20180112194628.GG9655@kernel.org>
References: <20180109133923.25406-1-jolsa@kernel.org>
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Em Tue, Jan 09, 2018 at 02:39:23PM +0100, Jiri Olsa escreveu:
> We need to increase output offset in each iteration,
> not decrease it as we currently do.
> 
> I guess we were lucky to finish in most cases in first
> iteration, so the bug never showed. However it shows a
> lot when working with big (~4GB) size data.

Try adding these in the future:

Fixes: 9c9f5a2f1944 ("perf tools: Introduce copyfile_offset() function")

Probably there are people tracking those to apply to older kernels :-)

- Arnaldo
 
> Link: http://lkml.kernel.org/n/tip-f4az7t2nxjbjz5tqrv83z64e@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/util/util.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
> index a789f952b3e9..443892dabedb 100644
> --- a/tools/perf/util/util.c
> +++ b/tools/perf/util/util.c
> @@ -210,7 +210,7 @@ static int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64
>  
>  		size -= ret;
>  		off_in += ret;
> -		off_out -= ret;
> +		off_out += ret;
>  	}
>  	munmap(ptr, off_in + size);
>  
> -- 
> 2.13.6