Re: [PATCH 53/59] drm/arc: Move to drm/tiny

From: Daniel Vetter <daniel@ffwll.ch>
To: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Daniel Vetter <daniel.vetter@intel.com>,
	Sam Ravnborg <sam@ravnborg.org>,
	"snps-arc@lists.infradead.org" <snps-arc@lists.infradead.org>
Subject: Re: [PATCH 53/59] drm/arc: Move to drm/tiny
Date: Tue, 9 Jun 2020 15:02:14 +0200	[thread overview]
Message-ID: <CAKMK7uFHCTkqoMGBW3QMjhJZaaakC_zYxxVW_C-LYRj0Yjt2gg@mail.gmail.com> (raw)
In-Reply-To: <CY4PR1201MB013654230A216EE7EB3C0E9BDE820@CY4PR1201MB0136.namprd12.prod.outlook.com>

Hi Eugeniy,

Very much appreciated, and kinda expected. That 2nd backtrace really
confuses me, so "something strange is going on" and the bisect looks
funny is within expectations. Hopefully we can track down what's going
on.

Thanks, Daniel

On Tue, Jun 9, 2020 at 2:08 PM Eugeniy Paltsev
<Eugeniy.Paltsev@synopsys.com> wrote:
>
> Hi Daniel,
>
> I've got pretty strange results so I need some time to investigate it and probably retest.
> I'll send you update in a few days.
>
> ---
>  Eugeniy Paltsev
>
>
> ________________________________________
> From: Daniel Vetter <daniel@ffwll.ch>
> Sent: Friday, June 5, 2020 22:55
> To: Eugeniy Paltsev
> Cc: Intel Graphics Development; DRI Development; Daniel Vetter; Sam Ravnborg; Alexey Brodkin; snps-arc@lists.infradead.org
> Subject: Re: [PATCH 53/59] drm/arc: Move to drm/tiny
>
> Hi Eugeniy,
>
> Thanks for testing. I looked at the second one (I hoped it would just
> magically disappear) and I still don't understand what's going on
> there. My patch series isn't touching that area at all, so really
> confused.
>
> I squashed in the bugfix from the previous round into the right
> patches, and pushed a branch with just the arcpgu changes here:
> https://urldefense.com/v3/__https://cgit.freedesktop.org/*danvet/drm/log/?h=for-eugeniy__;fg!!A4F2R9G_pg!IJ1o4XiXVdStPu--Q-SCTUpRbsbqrjX255R34nuD7L7ptPywOy4SKr21dwSpfOkXIVqH5pM$
>
> Maybe it's something in my pile of not-so-tested stuff :-)
>
> Can you pls test this? And if it still fails, try to bisect where it breaks?
>
> Thanks, Daniel
>
> On Thu, Jun 4, 2020 at 9:00 PM Eugeniy Paltsev
> <Eugeniy.Paltsev@synopsys.com> wrote:
> >
> > I've tested your change and one issue gone.
> >
> > However I still see kernel crash (due to invalid read in kernel mode by 0x0 address) on weston stop:
> > ----------------------------------->8-------------------------------------------
> > Oops
> > Path: (null)
> > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.7.0-rc6-01594-g4ceda91a4176-dirty #6
> > Workqueue: events drm_mode_rmfb_work_fn
> > Invalid Read @ 0x00000000 by insn @ drm_gem_fb_destroy+0x32/0x130
> > ECR: 0x00050100 EFA: 0x00000000 ERET: 0x813b9a76
> > STAT32: 0x80080602 [IE K     ]  BTA: 0x813b9a72
> > BLK: drm_gem_fb_destroy+0xc0/0x130
> >  SP: 0x9f055ea4  FP: 0x00000000
> > LPS: 0x813560ec LPE: 0x813560f0 LPC: 0x00000000
> > r00: 0x00000000 r01: 0x9f6a6100 r02: 0x00000001
> > r03: 0x9fd5dde8 r04: 0x810f5de8 r05: 0x00000000
> > r06: 0x00000000 r07: 0x00000000 r08: 0x000000e1
> > r09: 0x00000000 r10: 0x00000000 r11: 0x000000e1
> > r12: 0x813b9b04
> >
> > Stack Trace:
> >   drm_gem_fb_destroy+0x32/0x130
> >   drm_framebuffer_remove+0x1d2/0x358
> >   drm_mode_rmfb_work_fn+0x28/0x38
> >   process_one_work+0x19a/0x358
> >   worker_thread+0x2c4/0x494
> >   kthread+0xec/0x100
> >   ret_from_fork+0x18/0x1c
> > ----------------------------------->8-------------------------------------------
> >
> >
> > The stack traces may vary but always end in drm_gem_fb_destroy:
> > ----------------------------------->8-------------------------------------------
> > Stack Trace:
> >   drm_gem_fb_destroy+0x32/0x130
> >   drm_mode_rmfb+0x10e/0x148
> >   drm_ioctl_kernel+0x70/0xa0
> >   drm_ioctl+0x284/0x410
> >   ksys_ioctl+0xea/0xa3c
> >   EV_Trap+0xcc/0xd0
> > ----------------------------------->8-------------------------------------------
> > Stack Trace:
> >   drm_gem_fb_destroy+0x32/0x130
> >   drm_fb_release+0x66/0xb0
> >   drm_file_free.part.11+0x112/0x1bc
> >   drm_release+0x80/0x120
> >   __fput+0x98/0x1bc
> >   task_work_run+0x6e/0xa8
> >   do_exit+0x2b4/0x7fc
> >   do_group_exit+0x2a/0x8c
> >   get_signal+0x9a/0x5f0
> >   do_signal+0x86/0x23c
> >   resume_user_mode_begin+0x88/0xd0
> > ----------------------------------->8-------------------------------------------
> >
> >
> > ---
> >  Eugeniy Paltsev
> >
> >
> > ________________________________________
> > From: Daniel Vetter <daniel@ffwll.ch>
> > Sent: Thursday, June 4, 2020 14:19
> > To: Eugeniy Paltsev
> > Cc: Intel Graphics Development; DRI Development; Daniel Vetter; Sam Ravnborg; Alexey Brodkin
> > Subject: Re: [PATCH 53/59] drm/arc: Move to drm/tiny
> >
> > Hi Eugeniy,
> >
> > Apologies, somehow I missed your mail. I looked at the code again, and I
> > think I fumbled something. Does the below diff help to prevent the issues?
> >
> > Thanks, Daniel
> >
> >
> > diff --git a/drivers/gpu/drm/tiny/arcpgu.c b/drivers/gpu/drm/tiny/arcpgu.c
> > index 857812f25bec..33d812a5ad7f 100644
> > --- a/drivers/gpu/drm/tiny/arcpgu.c
> > +++ b/drivers/gpu/drm/tiny/arcpgu.c
> > @@ -228,6 +228,9 @@ static void arc_pgu_update(struct drm_simple_display_pipe *pipe,
> >         struct arcpgu_drm_private *arcpgu;
> >         struct drm_gem_cma_object *gem;
> >
> > +       if (!pipe->plane.state->fb)
> > +               return;
> > +
> >         arcpgu = pipe_to_arcpgu_priv(pipe);
> >         gem = drm_fb_cma_get_gem_obj(pipe->plane.state->fb, 0);
> >         arc_pgu_write(arcpgu, ARCPGU_REG_BUF0_ADDR, gem->paddr);
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - https://urldefense.com/v3/__http://blog.ffwll.ch__;!!A4F2R9G_pg!P0EvyJfMuDwqbeZmHZM5S9po30QWr4KgGrggRirNfgo7wrRXfnUO-8iq0AA4fQCW2WGPlDc$
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - https://urldefense.com/v3/__http://blog.ffwll.ch__;!!A4F2R9G_pg!IJ1o4XiXVdStPu--Q-SCTUpRbsbqrjX255R34nuD7L7ptPywOy4SKr21dwSpfOkXpn86Q20$

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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