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<p class="MsoNormal"><span lang="EN-US">Hi Christian & Emily<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I think the v4 fix for “fix force app kill hang” is still not good enough:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">First:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">See that in “sched_entity_fini”, we only call dma_fence_put(entity->last_scheduled” under the condition of “If (entity->fini_status)”, so
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">This way there is memory leak for the case of “entity->fini_stats ==0”<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Second:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">If we move dma_fence_put(entity->last_scheduled) out of the condition of “if (entity->fini_status)”, the memory leak issue can be fixed
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">But there will be kernel NULL pointer access, I think the time you call dma_fence_put(entity->last_scheduled”) may actually executed *<b>not</b>*<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">On the last scheduled fence of this entity, because it is run without “thread_park/unpark” pair which to make sure scheduler not dealing this entity<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">So with certain race issue, here is the scenario:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="margin-left:26.4pt;text-indent:-21.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">scheduler is doing the dma_fence_put() on the 1<sup>st</sup> fence,
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:26.4pt;text-indent:-21.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">scheduler set entity->last_scheduled to 1<sup>st</sup> fence<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:26.4pt;text-indent:-21.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">now sched_entity_fini() run, and it call dma_fence_put() on entity->last_scheduled
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:26.4pt;text-indent:-21.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">now this 1<sup>st</sup> fence is actually put double time and the real last fence won’t get put by expected
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">any idea?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">/Monk<o:p></o:p></span></p>
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