It needs to go into a namespace before reading a file.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/synthetic-events.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index e6978b2dee8f..d0d540d09196 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -391,6 +391,8 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
 	struct build_id _bid, *bid = &_bid;
 	struct dso *dso = NULL;
 	struct dso_id id;
+	struct nsinfo *nsi;
+	struct nscookie nc;
 	int rc;
 
 	if (is_kernel) {
@@ -410,8 +412,14 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
 		goto out;
 	}
 
+	nsi = nsinfo__new(event->pid);
+	nsinfo__mountns_enter(nsi, &nc);
+
 	rc = filename__read_build_id(event->filename, bid) > 0 ? 0 : -1;
 
+	nsinfo__mountns_exit(&nc);
+	nsinfo__put(nsi);
+
 out:
 	if (rc == 0) {
 		memcpy(event->build_id, bid->data, sizeof(bid->data));
-- 
2.37.3.968.ga6b4b080e4-goog

On 16/09/22 20:59, Namhyung Kim wrote:
> It needs to go into a namespace before reading a file.

This looks like a fix, in which case make it the first patch
and add a fixes tag?

> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/util/synthetic-events.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
> index e6978b2dee8f..d0d540d09196 100644
> --- a/tools/perf/util/synthetic-events.c
> +++ b/tools/perf/util/synthetic-events.c
> @@ -391,6 +391,8 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
>  	struct build_id _bid, *bid = &_bid;
>  	struct dso *dso = NULL;
>  	struct dso_id id;
> +	struct nsinfo *nsi;
> +	struct nscookie nc;
>  	int rc;
>  
>  	if (is_kernel) {
> @@ -410,8 +412,14 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
>  		goto out;
>  	}
>  
> +	nsi = nsinfo__new(event->pid);
> +	nsinfo__mountns_enter(nsi, &nc);
> +
>  	rc = filename__read_build_id(event->filename, bid) > 0 ? 0 : -1;
>  
> +	nsinfo__mountns_exit(&nc);
> +	nsinfo__put(nsi);
> +
>  out:
>  	if (rc == 0) {
>  		memcpy(event->build_id, bid->data, sizeof(bid->data));

On Tue, Sep 20, 2022 at 6:36 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 16/09/22 20:59, Namhyung Kim wrote:
> > It needs to go into a namespace before reading a file.
>
> This looks like a fix, in which case make it the first patch
> and add a fixes tag?

Good point, will do.

Thanks,
Namhyung


>
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  tools/perf/util/synthetic-events.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
> > index e6978b2dee8f..d0d540d09196 100644
> > --- a/tools/perf/util/synthetic-events.c
> > +++ b/tools/perf/util/synthetic-events.c
> > @@ -391,6 +391,8 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
> >       struct build_id _bid, *bid = &_bid;
> >       struct dso *dso = NULL;
> >       struct dso_id id;
> > +     struct nsinfo *nsi;
> > +     struct nscookie nc;
> >       int rc;
> >
> >       if (is_kernel) {
> > @@ -410,8 +412,14 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
> >               goto out;
> >       }
> >
> > +     nsi = nsinfo__new(event->pid);
> > +     nsinfo__mountns_enter(nsi, &nc);
> > +
> >       rc = filename__read_build_id(event->filename, bid) > 0 ? 0 : -1;
> >
> > +     nsinfo__mountns_exit(&nc);
> > +     nsinfo__put(nsi);
> > +
> >  out:
> >       if (rc == 0) {
> >               memcpy(event->build_id, bid->data, sizeof(bid->data));
>