<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/gpu/drm, branch v4.9.313</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drm/msm/mdp5: check the return of kzalloc()</title>
<updated>2022-04-27T11:14:11+00:00</updated>
<author>
<name>Xiaoke Wang</name>
<email>xkernel.wang@foxmail.com</email>
</author>
<published>2022-04-07T02:31:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=628dd78082bbe6b0122107b65d306c63484fa317'/>
<id>628dd78082bbe6b0122107b65d306c63484fa317</id>
<content type='text'>
[ Upstream commit 047ae665577776b7feb11bd4f81f46627cff95e7 ]

kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it to
prevent potential wrong memory access.

Besides, since mdp5_plane_reset() is void type, so we should better
set `plane-state` to NULL after releasing it.

Signed-off-by: Xiaoke Wang &lt;xkernel.wang@foxmail.com&gt;
Reviewed-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Patchwork: https://patchwork.freedesktop.org/patch/481055/
Link: https://lore.kernel.org/r/tencent_8E2A1C78140EE1784AB2FF4B2088CC0AB908@qq.com
Signed-off-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Signed-off-by: Rob Clark &lt;robdclark@chromium.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 047ae665577776b7feb11bd4f81f46627cff95e7 ]

kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it to
prevent potential wrong memory access.

Besides, since mdp5_plane_reset() is void type, so we should better
set `plane-state` to NULL after releasing it.

Signed-off-by: Xiaoke Wang &lt;xkernel.wang@foxmail.com&gt;
Reviewed-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Patchwork: https://patchwork.freedesktop.org/patch/481055/
Link: https://lore.kernel.org/r/tencent_8E2A1C78140EE1784AB2FF4B2088CC0AB908@qq.com
Signed-off-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Signed-off-by: Rob Clark &lt;robdclark@chromium.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdkfd: Check for potential null return of kmalloc_array()</title>
<updated>2022-04-20T07:06:45+00:00</updated>
<author>
<name>QintaoShen</name>
<email>unSimple1993@163.com</email>
</author>
<published>2022-03-24T08:26:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=32cf90a521dcc0f136db7ee5ba32bfe5f79e460e'/>
<id>32cf90a521dcc0f136db7ee5ba32bfe5f79e460e</id>
<content type='text'>
[ Upstream commit ebbb7bb9e80305820dc2328a371c1b35679f2667 ]

As the kmalloc_array() may return null, the 'event_waiters[i].wait' would lead to null-pointer dereference.
Therefore, it is better to check the return value of kmalloc_array() to avoid this confusion.

Signed-off-by: QintaoShen &lt;unSimple1993@163.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ebbb7bb9e80305820dc2328a371c1b35679f2667 ]

As the kmalloc_array() may return null, the 'event_waiters[i].wait' would lead to null-pointer dereference.
Therefore, it is better to check the return value of kmalloc_array() to avoid this confusion.

Signed-off-by: QintaoShen &lt;unSimple1993@163.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/imx: Fix memory leak in imx_pd_connector_get_modes</title>
<updated>2022-04-20T07:06:43+00:00</updated>
<author>
<name>José Expósito</name>
<email>jose.exposito89@gmail.com</email>
</author>
<published>2022-01-08T16:52:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d2c2758cfb0262637fd93350bdc8ad485fb1dd61'/>
<id>d2c2758cfb0262637fd93350bdc8ad485fb1dd61</id>
<content type='text'>
[ Upstream commit bce81feb03a20fca7bbdd1c4af16b4e9d5c0e1d3 ]

Avoid leaking the display mode variable if of_get_drm_display_mode
fails.

Fixes: 76ecd9c9fb24 ("drm/imx: parallel-display: check return code from of_get_drm_display_mode()")
Addresses-Coverity-ID: 1443943 ("Resource leak")
Signed-off-by: José Expósito &lt;jose.exposito89@gmail.com&gt;
Signed-off-by: Philipp Zabel &lt;p.zabel@pengutronix.de&gt;
Link: https://lore.kernel.org/r/20220108165230.44610-1-jose.exposito89@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bce81feb03a20fca7bbdd1c4af16b4e9d5c0e1d3 ]

Avoid leaking the display mode variable if of_get_drm_display_mode
fails.

Fixes: 76ecd9c9fb24 ("drm/imx: parallel-display: check return code from of_get_drm_display_mode()")
Addresses-Coverity-ID: 1443943 ("Resource leak")
Signed-off-by: José Expósito &lt;jose.exposito89@gmail.com&gt;
Signed-off-by: Philipp Zabel &lt;p.zabel@pengutronix.de&gt;
Link: https://lore.kernel.org/r/20220108165230.44610-1-jose.exposito89@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/tegra: Fix reference leak in tegra_dsi_ganged_probe</title>
<updated>2022-04-20T07:06:35+00:00</updated>
<author>
<name>Miaoqian Lin</name>
<email>linmq006@gmail.com</email>
</author>
<published>2022-01-10T06:53:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0e2f4e434e71dffd1085c3dccd676514bd71d316'/>
<id>0e2f4e434e71dffd1085c3dccd676514bd71d316</id>
<content type='text'>
[ Upstream commit 221e3638feb8bc42143833c9a704fa89b6c366bb ]

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore. Add put_device() call to fix this.

Fixes: e94236cde4d5 ("drm/tegra: dsi: Add ganged mode support")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Signed-off-by: Thierry Reding &lt;treding@nvidia.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 221e3638feb8bc42143833c9a704fa89b6c366bb ]

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore. Add put_device() call to fix this.

Fixes: e94236cde4d5 ("drm/tegra: dsi: Add ganged mode support")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Signed-off-by: Thierry Reding &lt;treding@nvidia.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/edid: Don't clear formats if using deep color</title>
<updated>2022-04-20T07:06:34+00:00</updated>
<author>
<name>Maxime Ripard</name>
<email>maxime@cerno.tech</email>
</author>
<published>2022-01-20T15:16:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f6a1864296a2a241f0b464f6e97986b5d9bf88d6'/>
<id>f6a1864296a2a241f0b464f6e97986b5d9bf88d6</id>
<content type='text'>
[ Upstream commit 75478b3b393bcbdca4e6da76fe3a9f1a4133ec5d ]

The current code, when parsing the EDID Deep Color depths, that the
YUV422 cannot be used, referring to the HDMI 1.3 Specification.

This specification, in its section 6.2.4, indeed states:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is not permitted for any Deep Color mode.

This indeed can be interpreted like the code does, but the HDMI 1.4
specification further clarifies that statement in its section 6.2.4:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is also 36-bit mode but does not require the further use
  of the Deep Color modes described in section 6.5.2 and 6.5.3.

This means that, even though YUV422 can be used with 12 bit per color,
it shouldn't be treated as a deep color mode.

This is also broken with YUV444 if it's supported by the display, but
DRM_EDID_HDMI_DC_Y444 isn't set. In such a case, the code will clear
color_formats of the YUV444 support set previously in
drm_parse_cea_ext(), but will not set it back.

Since the formats supported are already setup properly in
drm_parse_cea_ext(), let's just remove the code modifying the formats in
drm_parse_hdmi_deep_color_info()

Fixes: d0c94692e0a3 ("drm/edid: Parse and handle HDMI deep color modes.")
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-3-maxime@cerno.tech
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 75478b3b393bcbdca4e6da76fe3a9f1a4133ec5d ]

The current code, when parsing the EDID Deep Color depths, that the
YUV422 cannot be used, referring to the HDMI 1.3 Specification.

This specification, in its section 6.2.4, indeed states:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is not permitted for any Deep Color mode.

This indeed can be interpreted like the code does, but the HDMI 1.4
specification further clarifies that statement in its section 6.2.4:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is also 36-bit mode but does not require the further use
  of the Deep Color modes described in section 6.5.2 and 6.5.3.

This means that, even though YUV422 can be used with 12 bit per color,
it shouldn't be treated as a deep color mode.

This is also broken with YUV444 if it's supported by the display, but
DRM_EDID_HDMI_DC_Y444 isn't set. In such a case, the code will clear
color_formats of the YUV444 support set previously in
drm_parse_cea_ext(), but will not set it back.

Since the formats supported are already setup properly in
drm_parse_cea_ext(), let's just remove the code modifying the formats in
drm_parse_hdmi_deep_color_info()

Fixes: d0c94692e0a3 ("drm/edid: Parse and handle HDMI deep color modes.")
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-3-maxime@cerno.tech
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/edid: Always set RGB444</title>
<updated>2022-03-02T10:32:02+00:00</updated>
<author>
<name>Maxime Ripard</name>
<email>maxime@cerno.tech</email>
</author>
<published>2022-02-03T11:54:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=640f96f660fa9f81c81ac90798eb519171345931'/>
<id>640f96f660fa9f81c81ac90798eb519171345931</id>
<content type='text'>
commit ecbd4912a693b862e25cba0a6990a8c95b00721e upstream.

In order to fill the drm_display_info structure each time an EDID is
read, the code currently will call drm_add_display_info with the parsed
EDID.

drm_add_display_info will then call drm_reset_display_info to reset all
the fields to 0, and then set them to the proper value depending on the
EDID.

In the color_formats case, we will thus report that we don't support any
color format, and then fill it back with RGB444 plus the additional
formats described in the EDID Feature Support byte.

However, since that byte only contains format-related bits since the 1.4
specification, this doesn't happen if the EDID is following an earlier
specification. In turn, it means that for one of these EDID, we end up
with color_formats set to 0.

The EDID 1.3 specification never really specifies what it means by RGB
exactly, but since both HDMI and DVI will use RGB444, it's fairly safe
to assume it's supposed to be RGB444.

Let's move the addition of RGB444 to color_formats earlier in
drm_add_display_info() so that it's always set for a digital display.

Fixes: da05a5a71ad8 ("drm: parse color format support for digital displays")
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Reported-by: Matthias Reichl &lt;hias@horus.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220203115416.1137308-1-maxime@cerno.tech
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ecbd4912a693b862e25cba0a6990a8c95b00721e upstream.

In order to fill the drm_display_info structure each time an EDID is
read, the code currently will call drm_add_display_info with the parsed
EDID.

drm_add_display_info will then call drm_reset_display_info to reset all
the fields to 0, and then set them to the proper value depending on the
EDID.

In the color_formats case, we will thus report that we don't support any
color format, and then fill it back with RGB444 plus the additional
formats described in the EDID Feature Support byte.

However, since that byte only contains format-related bits since the 1.4
specification, this doesn't happen if the EDID is following an earlier
specification. In turn, it means that for one of these EDID, we end up
with color_formats set to 0.

The EDID 1.3 specification never really specifies what it means by RGB
exactly, but since both HDMI and DVI will use RGB444, it's fairly safe
to assume it's supposed to be RGB444.

Let's move the addition of RGB444 to color_formats earlier in
drm_add_display_info() so that it's always set for a digital display.

Fixes: da05a5a71ad8 ("drm: parse color format support for digital displays")
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Reported-by: Matthias Reichl &lt;hias@horus.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220203115416.1137308-1-maxime@cerno.tech
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/radeon: Fix backlight control on iMac 12,1</title>
<updated>2022-02-23T10:56:40+00:00</updated>
<author>
<name>Nicholas Bishop</name>
<email>nicholasbishop@google.com</email>
</author>
<published>2022-02-11T19:57:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ae5340cdd6f259cbd3f8e938236b7052c5d209e5'/>
<id>ae5340cdd6f259cbd3f8e938236b7052c5d209e5</id>
<content type='text'>
commit 364438fd629f7611a84c8e6d7de91659300f1502 upstream.

The iMac 12,1 does not use the gmux driver for backlight, so the radeon
backlight device is needed to set the brightness.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1838
Signed-off-by: Nicholas Bishop &lt;nicholasbishop@google.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 364438fd629f7611a84c8e6d7de91659300f1502 upstream.

The iMac 12,1 does not use the gmux driver for backlight, so the radeon
backlight device is needed to set the brightness.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1838
Signed-off-by: Nicholas Bishop &lt;nicholasbishop@google.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/nouveau: fix off by one in BIOS boundary checking</title>
<updated>2022-02-08T17:15:29+00:00</updated>
<author>
<name>Nick Lopez</name>
<email>github@glowingmonkey.org</email>
</author>
<published>2022-01-22T08:19:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d4b746e60fd8eaa8016e144223abe91158edcdad'/>
<id>d4b746e60fd8eaa8016e144223abe91158edcdad</id>
<content type='text'>
commit 1b777d4d9e383d2744fc9b3a09af6ec1893c8b1a upstream.

Bounds checking when parsing init scripts embedded in the BIOS reject
access to the last byte. This causes driver initialization to fail on
Apple eMac's with GeForce 2 MX GPUs, leaving the system with no working
console.

This is probably only seen on OpenFirmware machines like PowerPC Macs
because the BIOS image provided by OF is only the used parts of the ROM,
not a power-of-two blocks read from PCI directly so PCs always have
empty bytes at the end that are never accessed.

Signed-off-by: Nick Lopez &lt;github@glowingmonkey.org&gt;
Fixes: 4d4e9907ff572 ("drm/nouveau/bios: guard against out-of-bounds accesses to image")
Cc: &lt;stable@vger.kernel.org&gt; # v4.10+
Reviewed-by: Ilia Mirkin &lt;imirkin@alum.mit.edu&gt;
Reviewed-by: Karol Herbst &lt;kherbst@redhat.com&gt;
Signed-off-by: Karol Herbst &lt;kherbst@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220122081906.2633061-1-github@glowingmonkey.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 1b777d4d9e383d2744fc9b3a09af6ec1893c8b1a upstream.

Bounds checking when parsing init scripts embedded in the BIOS reject
access to the last byte. This causes driver initialization to fail on
Apple eMac's with GeForce 2 MX GPUs, leaving the system with no working
console.

This is probably only seen on OpenFirmware machines like PowerPC Macs
because the BIOS image provided by OF is only the used parts of the ROM,
not a power-of-two blocks read from PCI directly so PCs always have
empty bytes at the end that are never accessed.

Signed-off-by: Nick Lopez &lt;github@glowingmonkey.org&gt;
Fixes: 4d4e9907ff572 ("drm/nouveau/bios: guard against out-of-bounds accesses to image")
Cc: &lt;stable@vger.kernel.org&gt; # v4.10+
Reviewed-by: Ilia Mirkin &lt;imirkin@alum.mit.edu&gt;
Reviewed-by: Karol Herbst &lt;kherbst@redhat.com&gt;
Signed-off-by: Karol Herbst &lt;kherbst@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220122081906.2633061-1-github@glowingmonkey.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/msm: Fix wrong size calculation</title>
<updated>2022-02-08T17:15:27+00:00</updated>
<author>
<name>Xianting Tian</name>
<email>xianting.tian@linux.alibaba.com</email>
</author>
<published>2022-01-12T12:33:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=33dee0ad3f969dcec66a4cf23371656c3dc96148'/>
<id>33dee0ad3f969dcec66a4cf23371656c3dc96148</id>
<content type='text'>
commit 0a727b459ee39bd4c5ced19d6024258ac87b6b2e upstream.

For example, memory-region in .dts as below,
	reg = &lt;0x0 0x50000000 0x0 0x20000000&gt;

We can get below values,
struct resource r;
r.start = 0x50000000;
r.end	= 0x6fffffff;

So the size should be:
size = r.end - r.start + 1 = 0x20000000

Signed-off-by: Xianting Tian &lt;xianting.tian@linux.alibaba.com&gt;
Fixes: 072f1f9168ed ("drm/msm: add support for "stolen" mem")
Reviewed-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Link: https://lore.kernel.org/r/20220112123334.749776-1-xianting.tian@linux.alibaba.com
Signed-off-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0a727b459ee39bd4c5ced19d6024258ac87b6b2e upstream.

For example, memory-region in .dts as below,
	reg = &lt;0x0 0x50000000 0x0 0x20000000&gt;

We can get below values,
struct resource r;
r.start = 0x50000000;
r.end	= 0x6fffffff;

So the size should be:
size = r.end - r.start + 1 = 0x20000000

Signed-off-by: Xianting Tian &lt;xianting.tian@linux.alibaba.com&gt;
Fixes: 072f1f9168ed ("drm/msm: add support for "stolen" mem")
Reviewed-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Link: https://lore.kernel.org/r/20220112123334.749776-1-xianting.tian@linux.alibaba.com
Signed-off-by: Dmitry Baryshkov &lt;dmitry.baryshkov@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/i915: Flush TLBs before releasing backing store</title>
<updated>2022-01-29T09:15:58+00:00</updated>
<author>
<name>Tvrtko Ursulin</name>
<email>tvrtko.ursulin@intel.com</email>
</author>
<published>2021-10-19T12:27:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=84f4ab5b47d955ad2bb30115d7841d3e8f0994f4'/>
<id>84f4ab5b47d955ad2bb30115d7841d3e8f0994f4</id>
<content type='text'>
commit 7938d61591d33394a21bdd7797a245b65428f44c upstream.

We need to flush TLBs before releasing backing store otherwise userspace
is able to encounter stale entries if a) it is not declaring access to
certain buffers and b) it races with the backing store release from a
such undeclared execution already executing on the GPU in parallel.

The approach taken is to mark any buffer objects which were ever bound
to the GPU and to trigger a serialized TLB flush when their backing
store is released.

Alternatively the flushing could be done on VMA unbind, at which point
we would be able to ascertain whether there is potential a parallel GPU
execution (which could race), but essentially it boils down to paying
the cost of TLB flushes potentially needlessly at VMA unbind time (when
the backing store is not known to be going away so not needed for
safety), versus potentially needlessly at backing store relase time
(since we at that point cannot tell whether there is anything executing
on the GPU which uses that object).

Thereforce simplicity of implementation has been chosen for now with
scope to benchmark and refine later as required.

Signed-off-by: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Reported-by: Sushma Venkatesh Reddy &lt;sushma.venkatesh.reddy@intel.com&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Acked-by: Dave Airlie &lt;airlied@redhat.com&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Jon Bloomfield &lt;jon.bloomfield@intel.com&gt;
Cc: Joonas Lahtinen &lt;joonas.lahtinen@linux.intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@intel.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7938d61591d33394a21bdd7797a245b65428f44c upstream.

We need to flush TLBs before releasing backing store otherwise userspace
is able to encounter stale entries if a) it is not declaring access to
certain buffers and b) it races with the backing store release from a
such undeclared execution already executing on the GPU in parallel.

The approach taken is to mark any buffer objects which were ever bound
to the GPU and to trigger a serialized TLB flush when their backing
store is released.

Alternatively the flushing could be done on VMA unbind, at which point
we would be able to ascertain whether there is potential a parallel GPU
execution (which could race), but essentially it boils down to paying
the cost of TLB flushes potentially needlessly at VMA unbind time (when
the backing store is not known to be going away so not needed for
safety), versus potentially needlessly at backing store relase time
(since we at that point cannot tell whether there is anything executing
on the GPU which uses that object).

Thereforce simplicity of implementation has been chosen for now with
scope to benchmark and refine later as required.

Signed-off-by: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Reported-by: Sushma Venkatesh Reddy &lt;sushma.venkatesh.reddy@intel.com&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Acked-by: Dave Airlie &lt;airlied@redhat.com&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Jon Bloomfield &lt;jon.bloomfield@intel.com&gt;
Cc: Joonas Lahtinen &lt;joonas.lahtinen@linux.intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@intel.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
