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<p class="MsoNormal"><span lang="EN-US">Hi Christian <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">In amdgpu_cs_parser_bos(), it calls ttm_eu_backoff_reservation() if @need_pages not empty, is it safe ?<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">You see that if two threads in parallel running in cs_parser_bos(), if the thread1 did call backoff_reservation and continue, that leaves
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">All following reservation functions on root BO executed without protection from the lock, Meanwhile if this time thread2 call cs_parser_bos() in parallel, it can
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Get the lock of the reservation object on root BO (assume thread 1/2 share the same VM) immediately, so both of those threads consider they are
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Under protection of lock of reservation on the root bo. Do you think it’s a race issue ?<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">You know that I recently hit BUG() in reservation.c, and also found some weird bugs can be fixed by removing the kfree(obj->staged)
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">In reservation_object_reserve_shared(), and I think you right on the “staged” part that it shouldn’t be freed if everything go with rules (<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Always held the lock of the bo)<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">Thanks <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">/Monk<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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