Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Peter Zijlstra
On Mon, Jul 07, 2014 at 12:20:20PM +0200, Jiri Olsa wrote: > On Mon, Jul 07, 2014 at 11:04:28AM +0200, Peter Zijlstra wrote: > > On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: > > > From: Jiri Olsa > > > > > > While iterating siblings in perf_output_read_group we could > > > race

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Jiri Olsa
On Mon, Jul 07, 2014 at 11:04:28AM +0200, Peter Zijlstra wrote: > On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: > > From: Jiri Olsa > > > > While iterating siblings in perf_output_read_group we could > > race with addition and removal of sibling in perf_group_attach > > and

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Peter Zijlstra
On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: > From: Jiri Olsa > > While iterating siblings in perf_output_read_group we could > race with addition and removal of sibling in perf_group_attach > and perf_group_detach respective. So why would anybody do this? > While in

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Peter Zijlstra
On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: From: Jiri Olsa jo...@redhat.com While iterating siblings in perf_output_read_group we could race with addition and removal of sibling in perf_group_attach and perf_group_detach respective. So why would anybody do this? While in

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Jiri Olsa
On Mon, Jul 07, 2014 at 11:04:28AM +0200, Peter Zijlstra wrote: On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: From: Jiri Olsa jo...@redhat.com While iterating siblings in perf_output_read_group we could race with addition and removal of sibling in perf_group_attach and

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-07 Thread Peter Zijlstra
On Mon, Jul 07, 2014 at 12:20:20PM +0200, Jiri Olsa wrote: On Mon, Jul 07, 2014 at 11:04:28AM +0200, Peter Zijlstra wrote: On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: From: Jiri Olsa jo...@redhat.com While iterating siblings in perf_output_read_group we could race

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-02 Thread Jiri Olsa
hi, any feedback? thanks, jirka On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: > From: Jiri Olsa > > While iterating siblings in perf_output_read_group we could > race with addition and removal of sibling in perf_group_attach > and perf_group_detach respective. > > While in

Re: [PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-07-02 Thread Jiri Olsa
hi, any feedback? thanks, jirka On Wed, Jun 25, 2014 at 08:44:35PM +0200, Jiri Olsa wrote: From: Jiri Olsa jo...@redhat.com While iterating siblings in perf_output_read_group we could race with addition and removal of sibling in perf_group_attach and perf_group_detach respective. While

[PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-06-25 Thread Jiri Olsa
From: Jiri Olsa While iterating siblings in perf_output_read_group we could race with addition and removal of sibling in perf_group_attach and perf_group_detach respective. While in perf_output_read_group we are under active context, so the only sibling_list modification could come via IPI in:

[PATCH 1/1] perf: Prevent race in PERF_SAMPLE_READ group format sample output

2014-06-25 Thread Jiri Olsa
From: Jiri Olsa jo...@redhat.com While iterating siblings in perf_output_read_group we could race with addition and removal of sibling in perf_group_attach and perf_group_detach respective. While in perf_output_read_group we are under active context, so the only sibling_list modification could