[1/2] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

CoreSight doesn't allocate thread structure for unknown_thread in etm
auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't
contain valid tid and then cs_etm__mem_access() uses unknown_thread
instead as thread handler, this results in segmentation fault when
thread__find_addr_map() accesses thread handler.

This commit creates new thread data which is used by unknown_thread, so
CoreSight tracing can roll back to use unknown_thread if perf data
doesn't include valid thread info.  This commit also releases thread
data for initialization failure case and for normal auxtrace free flow.

Signed-off-by: Leo Yan <leo.yan@linaro.org>

---
 tools/perf/util/cs-etm.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

-- 
2.7.4

On 3 May 2018 at 09:18, Leo Yan <leo.yan@linaro.org> wrote:
> CoreSight doesn't allocate thread structure for unknown_thread in etm

> auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't

> contain valid tid and then cs_etm__mem_access() uses unknown_thread

> instead as thread handler, this results in segmentation fault when

> thread__find_addr_map() accesses thread handler.

>

> This commit creates new thread data which is used by unknown_thread, so

> CoreSight tracing can roll back to use unknown_thread if perf data

> doesn't include valid thread info.  This commit also releases thread

> data for initialization failure case and for normal auxtrace free flow.

>

> Signed-off-by: Leo Yan <leo.yan@linaro.org>

> ---

>  tools/perf/util/cs-etm.c | 25 +++++++++++++++++++++++--

>  1 file changed, 23 insertions(+), 2 deletions(-)

>

> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c

> index 6533b1a..417302c 100644

> --- a/tools/perf/util/cs-etm.c

> +++ b/tools/perf/util/cs-etm.c

> @@ -239,6 +239,7 @@ static void cs_etm__free(struct perf_session *session)

>         for (i = 0; i < aux->num_cpu; i++)

>                 zfree(&aux->metadata[i]);

>

> +       thread__zput(aux->unknown_thread);

>         zfree(&aux->metadata);

>         zfree(&aux);

>  }

> @@ -266,6 +267,7 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u64 address,

>         if (!thread) {

>                 if (cpumode != PERF_RECORD_MISC_KERNEL)

>                         return -EINVAL;

> +


Extra line, please remove.

With this change:

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>


>                 thread = etmq->etm->unknown_thread;

>         }

>

> @@ -1355,6 +1357,23 @@ int cs_etm__process_auxtrace_info(union perf_event *event,

>         etm->auxtrace.free = cs_etm__free;

>         session->auxtrace = &etm->auxtrace;

>

> +       etm->unknown_thread = thread__new(999999999, 999999999);

> +       if (!etm->unknown_thread)

> +               goto err_free_queues;

> +

> +       /*

> +        * Initialize list node so that at thread__zput() we can avoid

> +        * segmentation fault at list_del_init().

> +        */

> +       INIT_LIST_HEAD(&etm->unknown_thread->node);

> +

> +       err = thread__set_comm(etm->unknown_thread, "unknown", 0);

> +       if (err)

> +               goto err_delete_thread;

> +

> +       if (thread__init_map_groups(etm->unknown_thread, etm->machine))

> +               goto err_delete_thread;

> +

>         if (dump_trace) {

>                 cs_etm__print_auxtrace_info(auxtrace_info->priv, num_cpu);

>                 return 0;

> @@ -1369,16 +1388,18 @@ int cs_etm__process_auxtrace_info(union perf_event *event,

>

>         err = cs_etm__synth_events(etm, session);

>         if (err)

> -               goto err_free_queues;

> +               goto err_delete_thread;

>

>         err = auxtrace_queues__process_index(&etm->queues, session);

>         if (err)

> -               goto err_free_queues;

> +               goto err_delete_thread;

>

>         etm->data_queued = etm->queues.populated;

>

>         return 0;

>

> +err_delete_thread:

> +       thread__zput(etm->unknown_thread);

>  err_free_queues:

>         auxtrace_queues__free(&etm->queues);

>         session->auxtrace = NULL;

> --

> 2.7.4

>

On Tue, May 08, 2018 at 11:01:30AM -0600, Mathieu Poirier wrote:
> On 3 May 2018 at 09:18, Leo Yan <leo.yan@linaro.org> wrote:

> > CoreSight doesn't allocate thread structure for unknown_thread in etm

> > auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't

> > contain valid tid and then cs_etm__mem_access() uses unknown_thread

> > instead as thread handler, this results in segmentation fault when

> > thread__find_addr_map() accesses thread handler.

> >

> > This commit creates new thread data which is used by unknown_thread, so

> > CoreSight tracing can roll back to use unknown_thread if perf data

> > doesn't include valid thread info.  This commit also releases thread

> > data for initialization failure case and for normal auxtrace free flow.

> >

> > Signed-off-by: Leo Yan <leo.yan@linaro.org>

> > ---

> >  tools/perf/util/cs-etm.c | 25 +++++++++++++++++++++++--

> >  1 file changed, 23 insertions(+), 2 deletions(-)

> >

> > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c

> > index 6533b1a..417302c 100644

> > --- a/tools/perf/util/cs-etm.c

> > +++ b/tools/perf/util/cs-etm.c

> > @@ -239,6 +239,7 @@ static void cs_etm__free(struct perf_session *session)

> >         for (i = 0; i < aux->num_cpu; i++)

> >                 zfree(&aux->metadata[i]);

> >

> > +       thread__zput(aux->unknown_thread);

> >         zfree(&aux->metadata);

> >         zfree(&aux);

> >  }

> > @@ -266,6 +267,7 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u64 address,

> >         if (!thread) {

> >                 if (cpumode != PERF_RECORD_MISC_KERNEL)

> >                         return -EINVAL;

> > +

> 

> Extra line, please remove.

> 

> With this change:

> 

> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>


Thanks for reviewing, Mathieu.  Will spin new patches and send out.

[...]

Thanks,
Leo Yan