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: Fri, 5 Jun 2020 21:55:53 +0200	[thread overview]
Message-ID: <CAKMK7uESUnLR1N07T513RjGUAp8FA6oHaO1Y+uvTKpFuM_8+gQ@mail.gmail.com> (raw)
In-Reply-To: <CY4PR1201MB013642EB94E07AED91813A5FDE890@CY4PR1201MB0136.namprd12.prod.outlook.com>

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://cgit.freedesktop.org/~danvet/drm/log/?h=for-eugeniy

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 - http://blog.ffwll.ch
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