linux-kernel - Re: [BUG] function_graph trace causes hang when using sleepgraph (4.15.0-rc1 and newer)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 08 Jan 2018 17:25:15 -0800
From:   Todd Brandt <todd.e.brandt@...ux.intel.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        len.brown@...el.com, todd.e.brandt@...el.com
Subject: Re: [BUG] function_graph trace causes  hang when using sleepgraph
 (4.15.0-rc1 and newer)

On Mon, 2018-01-08 at 20:07 -0500, Steven Rostedt wrote:
> On Mon, 08 Jan 2018 17:02:29 -0800
> Todd Brandt <todd.e.brandt@...ux.intel.com> wrote:
> 
> > Stephen, the problem is reversed by removing the following two
> > commits,
> > the one the bisect showed and the very next. So the problem is
> > here:
> > 
> > commit 1a149d7d3f45d311da1f63473736c05f30ae8a75
> > Author: Steven Rostedt (VMware) <rostedt@...dmis.org>
> > Date:   Fri Sep 22 16:59:02 2017 -0400
> > 
> >     ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler
> 
> This one still doesn't make sense, for why it would cause the hang.
> 
> 
> > commit 12ecef0cb12102d8c034770173d2d1363cb97d52
> > Author: Steven Rostedt (VMware) <rostedt@...dmis.org>
> > Date:   Thu Sep 21 16:22:49 2017 -0400
> > 
> >     tracing: Reverse the order of trace_types_lock and event_mutex
> 
> This one does.
> 
> Can you run lockdep when you do this and see if lockdep catches
> anything? If it does, it should point directly to where the inversed
> locking happened.

Can you reproduce the issue there? I just want to be sure it's not
something local to our machines here, as long as you have CONFIG_PM
enabled it should work the same hopefully. 

I'll give lockdep a try here.

> 
> -- Steve