[PATCH] perf tools: Fix copyfile_offset update of output offset

[PATCH] perf tools: Fix copyfile_offset update of output offset

[Jiri Olsa]

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.

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

Re: [PATCH] perf tools: Fix copyfile_offset update of output offset

[Arnaldo Carvalho de Melo]

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

[tip:perf/core] perf tools: Fix copyfile_offset update of output offset

[tip-bot for Jiri Olsa]

Commit-ID:  fa1195ccc0af2d121abe0fe266a1caee8c265eea
Gitweb:     https://git.kernel.org/tip/fa1195ccc0af2d121abe0fe266a1caee8c265eea
Author:     Jiri Olsa <jolsa@kernel.org>
AuthorDate: Tue, 9 Jan 2018 14:39:23 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Jan 2018 16:57:16 -0300

perf tools: Fix copyfile_offset update of output offset

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.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 9c9f5a2f1944 ("perf tools: Introduce copyfile_offset() function")
Link: http://lkml.kernel.org/r/20180109133923.25406-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 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 a789f95..443892d 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);