linux-kernel - Re: [PATCH] drm/i915: Increase the amount of defense before computing vblank timestamps

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]

Message-Id: <201101230856.42744.chris2553@googlemail.com>
Date:	Sun, 23 Jan 2011 08:56:42 +0000
From:	Chris Clayton <chris2553@...glemail.com>
To:	Chris Wilson <chris@...is-wilson.co.uk>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/i915: Increase the amount of defense before computing vblank timestamps

On Saturday 22 January 2011, Chris Wilson wrote:
> On Sat, 22 Jan 2011 11:18:53 +0000, Chris Clayton <chris2553@...glemail.com> 
wrote:
> > On Saturday 22 January 2011, Chris Wilson wrote:
> > > Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
> > > ---
> > >
> > > Chris, does this help?
> >
> > Sorry Chris, X still doesn't start with this patch applied. The symptoms
> > are slightly different in that the monitor doesn't go into power saving
> > mode, but the screen is still black and I have to recycle the power to
> > get the machine back.
> > The messages in the log file has changed though.We now have:
>
> Despite appearances to the contrary, it is a step forward. We have the
> crash under control, and now need to tackle the underlying problem.
>
> However, I'm worried by the fact that no CRTCs are attached. Is this not
> using KMS?
>

No KMS is not configured in. I found that under an earlier version of the kernel 
it caused my kernel to lock up, so I configured it out. I meant to investigate 
further and report it, but then forgot. I'll turn KMS on and report the 
outcome.

> > > If you can convert the address to a line number that would pinpoint the
> >
> > Not done that before and nothing jumped out of my search on google, so
> > how do I go about getting the line number for you, please?
>
> Something like:
>
> $ gdb drivers/gpu/drm/drm.ko
> (gdb) list *drm_calc_vbltimestamp_from_scanoutpos+0x3e
>
> should do the trick (if compiled as a module, vmlinux otherwise)

Thanks for the tutoring. I get

(gdb) list *drm_calc_vbltimestamp_from_scanoutpos+0x3e
0x6afe is in drm_calc_vbltimestamp_from_scanoutpos 
(drivers/gpu/drm/drm_irq.c:590).
585                     DRM_ERROR("Called from driver w/o 
get_scanout_position()!?\n");
586                     return -EIO;
587             }
588
589             mode = &refcrtc->hwmode;
590             vtotal = mode->crtc_vtotal;
591             vdisplay = mode->crtc_vdisplay;
592
593             /* Durations of frames, lines, pixels in nanoseconds. */
594             framedur_ns = refcrtc->framedur_ns;


Chris
> -Chris

-- 
The more I see, the more I know. The more I know, the less I understand. 
Changing Man - Paul Weller
--
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/