linux-kernel - Re: [PATCH v3] kernel: sched: fix preempt_disable_ip recodring for preempt

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] [day] [month] [year] [list]

Date:	Thu, 3 Mar 2016 13:51:41 +0100
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	Daniel Bristot de Oliveira <bristot@...hat.com>,
	Steven Rostedt <rostedt@...dmis.org>
Cc:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] kernel: sched: fix preempt_disable_ip recodring for
 preempt_disable()

On 02/26/2016 08:11 PM, Daniel Bristot de Oliveira wrote:
> 
> 
> On 02/26/2016 10:54 AM, Sebastian Andrzej Siewior wrote:
>> -		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
>> +		trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
> 
> If !lock_functions(CALLER_ADDR0), the start/stop_critical_timing() will
> be called with parent_ip == ip.
> 
> Hence, the following trace on start_critical_timing():
> 
>         __trace_function(tr, ip, parent_ip, flags, preempt_count());
> 
> Will show the function calling itself.
> 
> Is it a problem? am I missing something?

It might be that for !lock_functions() we get the same caller. But then
get_parent_ip() was not inlined (in my .o file) so ADDR1 in
get_parent_ip() should correspond to ADDR0 in the inline case.

> -- Daniel

Sebastian