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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - i915 "kernel NULL pointer dereference" in kernel-4.18.20"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108850#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - i915 "kernel NULL pointer dereference" in kernel-4.18.20"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108850">bug 108850</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>Missing backport of
commit d9d117e40d4ffc03438177eeac83d96dfeee76be
Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Date: Mon Jun 11 18:18:25 2018 +0100
drm/i915/ringbuffer: Serialize load of PD_DIR
After triggering the mm switch with a load of PD_DIR, which may be
deferred unto the MI_SET_CONTEXT on rcs, serialise the next commands
with that load by posting a read of PD_DIR (or else those subsequent
commands may access the stale page tables).
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Cc: Joonas Lahtinen <<a href="mailto:joonas.lahtinen@linux.intel.com">joonas.lahtinen@linux.intel.com</a>>
Cc: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>>
Cc: Matthew Auld <<a href="mailto:matthew.william.auld@gmail.com">matthew.william.auld@gmail.com</a>>
Reviewed-by: Joonas Lahtinen <<a href="mailto:joonas.lahtinen@linux.intel.com">joonas.lahtinen@linux.intel.com</a>>
Link:
<a href="https://patchwork.freedesktop.org/patch/msgid/20180611171825.13678-2-c">https://patchwork.freedesktop.org/patch/msgid/20180611171825.13678-2-c</a>
<a href="mailto:hris@chris-wilson.co.uk">hris@chris-wilson.co.uk</a>
or at least the active ingredient of always allocating the engine->scratch.</pre>
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