linux-kernel - Re: -rt doesn't compile for UML

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:	Wed, 28 Nov 2007 17:05:01 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	jdike@...toit.com, user-mode-linux-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: Re: -rt doesn't compile for UML


* Miklos Szeredi <miklos@...redi.hu> wrote:

> > it doesnt need it - turn IRQOFF_TRACING off.
> 
> # CONFIG_CRITICAL_IRQSOFF_TIMING is not set
> 
> This seems to be off.
> 
> But latency_trace.c uses irqs_disabled_flags(), which is defined in 
> <linux/irqflags.h> only if CONFIG_TRACE_IRQFLAGS_SUPPORT is set.
> 
> So perhaps latency_trace.c should be using raw_irqs_disabled_flags() 
> instead.  But UML doesn't define that either and I have no idea how to 
> do that, so this is still not solved yet.

irqs_disabled_flags() gives us a nonessential bit of the trace output:

                 _------=> CPU#
                / _-----=> irqs-off
               | / _----=> need-resched
               || / _---=> hardirq/softirq
               ||| / _--=> preempt-depth
               |||| /
               |||||     delay
   cmd     pid ||||| time  |   caller
      \   /    |||||   \   |   /
 privoxy-12926 1.Ns1    0us : ktime_get_ts (ktime_get)
 privoxy-12926 1.Ns1    0us : getnstimeofday (ktime_get_ts)
 privoxy-12926 1.Ns1    1us : set_normalized_timespec (ktime_get_ts)
 privoxy-12926 1.Ns1    1us : rb_first (htb_dequeue)

it's the 'irqs-off' flag, which is 'd', 'D' or '.'.

so you can define irqs_off_flags to always-0 and you should be able to 
get pretty good traces still. It should have no functional impact.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/