Re: [patch v4 19/24] btrace, linux: fix memory leak when reading branch trace

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Wed, 03 Jul 2013 11:14:29 +0200, Markus Metzger wrote:
> When it takes more than one iteration to read the BTS trace, the trace from the
> previous iteration is leaked.  Fix it.
> 
> 2013-07-03  Markus Metzger  <markus.t.metzger@intel.com>
> 
> 	* common/linux-btrace.c (linux_read_btrace): Free trace from
> 	previous iteration.
> 
> 
> ---
>  gdb/common/linux-btrace.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/gdb/common/linux-btrace.c b/gdb/common/linux-btrace.c
> index 4880f41..b30a6ec 100644
> --- a/gdb/common/linux-btrace.c
> +++ b/gdb/common/linux-btrace.c
> @@ -522,6 +522,9 @@ linux_read_btrace (struct btrace_target_info *tinfo,
>      {
>        data_head = header->data_head;
>  
> +      /* Delete any leftover trace from the previous iteration.  */
> +      VEC_truncate (btrace_block_s, btrace, 0);

This still leaks, you should do VEC_free.  Later you do:
	*btrace = perf_event_read_bts (tinfo, begin, end, start, size);

which overwrites the whole 'struct *' containing validly setup VEC data just
with zero elements.


> +
>        /* If there's new trace, let's read it.  */
>        if (data_head != tinfo->data_head)
>  	{
> -- 
> 1.7.1