* [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup
@ 2015-12-19 1:27 Matt Roper
2015-12-19 10:20 ` ✗ warning: Fi.CI.BAT Patchwork
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Matt Roper @ 2015-12-19 1:27 UTC (permalink / raw)
To: dri-devel; +Cc: intel-gfx, Daniel Vetter
pan_display_atomic() calls drm_atomic_clean_old_fb() to sanitize the
legacy FB fields (plane->fb and plane->old_fb). However it was building
the plane mask to pass to this function incorrectly (the bitwise OR was
using plane indices rather than plane masks). The end result was that
sometimes the legacy pointers would become out of sync with the atomic
pointers. If another operation tried to re-set the same FB onto the
plane, we might end up with the pointers back in sync, but improper
reference counts, which would eventually lead to system crashes when we
accessed a pointer to a prematurely-destroyed FB.
The cause here was a very subtle bug introduced in commit:
commit 07d3bad6c1210bd21e85d084807ef4ee4ac43a78
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Wed Nov 11 11:29:11 2015 +0100
drm/core: Fix old_fb handling in pan_display_atomic.
I found the crashes were most easily reproduced (on i915 at least) by
starting X and then VT switching to a VT that wasn't running a console
instance...the sequence of vt/fbcon entries that happen in that case
trigger a reference count mismatch and crash the system.
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93313
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
drivers/gpu/drm/drm_fb_helper.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 69cbab5..1e103c4 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1251,7 +1251,7 @@ retry:
goto fail;
plane = mode_set->crtc->primary;
- plane_mask |= drm_plane_index(plane);
+ plane_mask |= (1 << drm_plane_index(plane));
plane->old_fb = plane->fb;
}
--
2.1.4
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* ✗ warning: Fi.CI.BAT
2015-12-19 1:27 [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Matt Roper
@ 2015-12-19 10:20 ` Patchwork
2015-12-21 8:55 ` [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Daniel Vetter
2015-12-22 8:37 ` Maarten Lankhorst
2 siblings, 0 replies; 4+ messages in thread
From: Patchwork @ 2015-12-19 10:20 UTC (permalink / raw)
To: Matt Roper; +Cc: intel-gfx
== Summary ==
Built on 7cdc548e77f503593b83a1c5d58f4dcc862c17e2 drm-intel-nightly: 2015y-12m-18d-19h-26m-21s UTC integration manifest
Test gem_storedw_loop:
Subgroup basic-render:
pass -> DMESG-WARN (skl-i7k-2)
Test kms_flip:
Subgroup basic-flip-vs-dpms:
pass -> DMESG-WARN (skl-i7k-2)
Subgroup basic-flip-vs-modeset:
dmesg-warn -> PASS (skl-i5k-2)
dmesg-warn -> PASS (byt-nuc)
Subgroup basic-flip-vs-wf_vblank:
pass -> DMESG-WARN (byt-nuc)
Test kms_pipe_crc_basic:
Subgroup read-crc-pipe-a:
dmesg-warn -> PASS (snb-x220t)
pass -> DMESG-WARN (bdw-ultra)
Subgroup read-crc-pipe-a-frame-sequence:
dmesg-warn -> PASS (byt-nuc)
Subgroup read-crc-pipe-c:
pass -> DMESG-WARN (skl-i5k-2)
dmesg-warn -> PASS (skl-i7k-2)
Subgroup suspend-read-crc-pipe-a:
pass -> DMESG-WARN (snb-x220t)
Subgroup suspend-read-crc-pipe-b:
pass -> DMESG-WARN (bdw-nuci7)
Test pm_rpm:
Subgroup basic-pci-d3-state:
dmesg-warn -> PASS (bdw-ultra)
bdw-nuci7 total:135 pass:124 dwarn:2 dfail:0 fail:0 skip:9
bdw-ultra total:132 pass:124 dwarn:2 dfail:0 fail:0 skip:6
byt-nuc total:135 pass:120 dwarn:2 dfail:0 fail:0 skip:13
hsw-brixbox total:135 pass:126 dwarn:2 dfail:0 fail:0 skip:7
hsw-gt2 total:135 pass:130 dwarn:1 dfail:0 fail:0 skip:4
ilk-hp8440p total:135 pass:100 dwarn:0 dfail:0 fail:0 skip:35
ivb-t430s total:135 pass:127 dwarn:2 dfail:0 fail:0 skip:6
skl-i5k-2 total:135 pass:122 dwarn:5 dfail:0 fail:0 skip:8
skl-i7k-2 total:135 pass:121 dwarn:6 dfail:0 fail:0 skip:8
snb-dellxps total:135 pass:121 dwarn:2 dfail:0 fail:0 skip:12
snb-x220t total:135 pass:121 dwarn:2 dfail:0 fail:1 skip:11
Results at /archive/results/CI_IGT_test/Patchwork_729/
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http://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup
2015-12-19 1:27 [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Matt Roper
2015-12-19 10:20 ` ✗ warning: Fi.CI.BAT Patchwork
@ 2015-12-21 8:55 ` Daniel Vetter
2015-12-22 8:37 ` Maarten Lankhorst
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2015-12-21 8:55 UTC (permalink / raw)
To: Matt Roper; +Cc: Daniel Vetter, intel-gfx, dri-devel
On Fri, Dec 18, 2015 at 05:27:01PM -0800, Matt Roper wrote:
> pan_display_atomic() calls drm_atomic_clean_old_fb() to sanitize the
> legacy FB fields (plane->fb and plane->old_fb). However it was building
> the plane mask to pass to this function incorrectly (the bitwise OR was
> using plane indices rather than plane masks). The end result was that
> sometimes the legacy pointers would become out of sync with the atomic
> pointers. If another operation tried to re-set the same FB onto the
> plane, we might end up with the pointers back in sync, but improper
> reference counts, which would eventually lead to system crashes when we
> accessed a pointer to a prematurely-destroyed FB.
>
> The cause here was a very subtle bug introduced in commit:
>
> commit 07d3bad6c1210bd21e85d084807ef4ee4ac43a78
> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Date: Wed Nov 11 11:29:11 2015 +0100
>
> drm/core: Fix old_fb handling in pan_display_atomic.
>
> I found the crashes were most easily reproduced (on i915 at least) by
> starting X and then VT switching to a VT that wasn't running a console
> instance...the sequence of vt/fbcon entries that happen in that case
> trigger a reference count mismatch and crash the system.
>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93313
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Applied to drm-misc, thanks.
-Daniel
> ---
> drivers/gpu/drm/drm_fb_helper.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 69cbab5..1e103c4 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1251,7 +1251,7 @@ retry:
> goto fail;
>
> plane = mode_set->crtc->primary;
> - plane_mask |= drm_plane_index(plane);
> + plane_mask |= (1 << drm_plane_index(plane));
> plane->old_fb = plane->fb;
> }
>
> --
> 2.1.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup
2015-12-19 1:27 [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Matt Roper
2015-12-19 10:20 ` ✗ warning: Fi.CI.BAT Patchwork
2015-12-21 8:55 ` [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Daniel Vetter
@ 2015-12-22 8:37 ` Maarten Lankhorst
2 siblings, 0 replies; 4+ messages in thread
From: Maarten Lankhorst @ 2015-12-22 8:37 UTC (permalink / raw)
To: Matt Roper, dri-devel; +Cc: Daniel Vetter, intel-gfx
Op 19-12-15 om 02:27 schreef Matt Roper:
> pan_display_atomic() calls drm_atomic_clean_old_fb() to sanitize the
> legacy FB fields (plane->fb and plane->old_fb). However it was building
> the plane mask to pass to this function incorrectly (the bitwise OR was
> using plane indices rather than plane masks). The end result was that
> sometimes the legacy pointers would become out of sync with the atomic
> pointers. If another operation tried to re-set the same FB onto the
> plane, we might end up with the pointers back in sync, but improper
> reference counts, which would eventually lead to system crashes when we
> accessed a pointer to a prematurely-destroyed FB.
>
> The cause here was a very subtle bug introduced in commit:
>
> commit 07d3bad6c1210bd21e85d084807ef4ee4ac43a78
> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Date: Wed Nov 11 11:29:11 2015 +0100
>
> drm/core: Fix old_fb handling in pan_display_atomic.
>
> I found the crashes were most easily reproduced (on i915 at least) by
> starting X and then VT switching to a VT that wasn't running a console
> instance...the sequence of vt/fbcon entries that happen in that case
> trigger a reference count mismatch and crash the system.
>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93313
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
> drivers/gpu/drm/drm_fb_helper.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 69cbab5..1e103c4 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1251,7 +1251,7 @@ retry:
> goto fail;
>
> plane = mode_set->crtc->primary;
> - plane_mask |= drm_plane_index(plane);
> + plane_mask |= (1 << drm_plane_index(plane));
> plane->old_fb = plane->fb;
> }
>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
_______________________________________________
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Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-12-22 8:37 UTC | newest]
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2015-12-19 1:27 [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Matt Roper
2015-12-19 10:20 ` ✗ warning: Fi.CI.BAT Patchwork
2015-12-21 8:55 ` [PATCH] drm/fb-helper: Use proper plane mask for fb cleanup Daniel Vetter
2015-12-22 8:37 ` Maarten Lankhorst
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