Re: [PATCH v9 00/14] Add support for remote unwind

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
	peterz@infradead.org, mingo@redhat.com,
	alexander.shishkin@linux.intel.com, wangnan0@huawei.com,
	jpoimboe@redhat.com, ak@linux.intel.com, eranian@google.com,
	namhyung@kernel.org, adrian.hunter@intel.com,
	sukadev@linux.vnet.ibm.com, masami.hiramatsu.pt@hitachi.com,
	tumanova@linux.vnet.ibm.com, kan.liang@intel.com,
	penberg@kernel.org, dsahern@gmail.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 00/14] Add support for remote unwind
Date: Fri, 3 Jun 2016 18:09:27 -0300	[thread overview]
Message-ID: <20160603210927.GB3095@kernel.org> (raw)
In-Reply-To: <20160603210602.GA3095@kernel.org>

Em Fri, Jun 03, 2016 at 06:06:02PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Jun 03, 2016 at 04:42:05PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Jun 03, 2016 at 09:06:29AM +0200, Jiri Olsa escreveu:
> > > On Fri, Jun 03, 2016 at 03:33:09AM +0000, He Kuang wrote:
> > > > v9:
> > > >  - Change function unwind__register_ops() to static.
> > > >  - Move up unwind__prepare_access() in thread__insert_map() and save
> > > >    map_groups__remove() call.
> > > >  - Enclose multiple line if/else into braces.
> > > >  - Fix miss modified function declaration for unwind__prepare_access()
> > > >    in patch 10.
> >  
> > > for patchset:
> >  
> > > Acked-by: Jiri Olsa <jolsa@kernel.org>
> > 
> > Thanks, applied, build testing.
> 
> Build tested went ok, but then 'perf top' crashes:
> 
> [root@jouet ~]# perf top
> perf: Segmentation fault
> -------- backtrace --------
> perf[0x55591b]
> /lib64/libc.so.6(+0x34ab0)[0x7f38ad9c1ab0]
> perf(normalize_arch+0x27)[0x534797]
> perf(unwind__prepare_access+0xbb)[0x52b15b]
> perf(thread__insert_map+0x27)[0x4d4837]
> perf(machine__process_mmap2_event+0xd7)[0x4ca187]
> perf(perf_event__synthesize_mmap_events+0x3e2)[0x491b32]
> perf(perf_event__synthesize_threads+0x445)[0x492635]
> perf(cmd_top+0xee0)[0x442f50]
> perf[0x486a91]
> perf(main+0x6ee)[0x42485e]
> /lib64/libc.so.6(__libc_start_main+0xf0)[0x7f38ad9ad580]
> perf(_start+0x29)[0x424949]
> [0x0]
> [root@jouet ~]#
> 
> And I bet that 'perf trace' will too, lemme see, well, it crashes even
> more spetacularly, but that is the topic of another bug report, will
> send soon.
> 
> Anyway, please try your patchkit with 'perf top' and 'perf trace', as
> both don't use perf.data files, i.e. they work 'live', so probably
> things that you touch in normalize_arch() are not initialized and need
> to be setup.

Ah, no need to resend the whole patchkit, just find out what is the bug
and send me a patch and I'll insert it at the right point to avoid
introducing a bisect breaking point.

Your patchkit is in my perf/unwind branch at my tree, I already added
Jiri's Acked-by in all the patches.

git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git

Thanks,

- Arnaldo
-