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Date: Tue, 13 Jun 2017 20:54:54 +0200
From: Jiri Olsa <jolsa@redhat.com>
To: David Carrillo-Cisneros <davidcc@google.com>
Cc: linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>, Simon Que <sque@chromium.org>,
        Wang Nan <wangnan0@huawei.com>, Jiri Olsa <jolsa@kernel.org>,
        He Kuang <hekuang@huawei.com>, Masami Hiramatsu <mhiramat@kernel.org>,
        Stephane Eranian <eranian@google.com>, Paul Turner <pjt@google.com>
Subject: Re: [PATCH v4 15/16] perf tools: add feature header record to
 pipe-mode
Message-ID: <20170613185454.GE6092@krava>
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 <20170613042932.141842-16-davidcc@google.com>
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On Mon, Jun 12, 2017 at 09:29:31PM -0700, David Carrillo-Cisneros wrote:

SNIP

>  
>  void perf_event__print_totals(void);
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index ddfaf157913d..6f6a54c15cb0 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -34,6 +34,7 @@
>  #include "data.h"
>  #include <api/fs/fs.h>
>  #include "asm/bug.h"
> +#include "tool.h"
>  
>  #include "sane_ctype.h"
>  
> @@ -97,11 +98,14 @@ static int __do_write_buf(struct feat_fd *ff,  const void *buf, size_t size)
>  
>  retry:
>  	if (size > (ff->size - ff->offset)) {
> -		addr = realloc(ff->buf, ff->size << 1);
> +		size = ff->size << 1;
> +		if (size > page_size)

event size could be 0xffff - sizeof(struct perf_event_header)
also the initial size is most likely > page_size anyway

please put this into the patch that introduced __do_write_buf

jirka