On Fri, Dec 05, 2014 at 06:02:35PM +0000, John Harrison wrote: > But yes, the reasoning why it crashes without the zero fill is correct. > Dodgy context pointers that used to be ignored now get processed. Doing the > zero fill keeps it all sane. > > On 05/12/2014 17:54, John Harrison wrote: > >This is already part of the seqno/request patch series and has been right > >from the start. See email 'drm/i915: Zero fill the request structure'. > > > >On 05/12/2014 17:54, Mika Kuoppala wrote: > >>Otherwise we might end up referencing uninitialized fields. > >>This is apparent when we try to cleanup the preallocated request > >>on ring reset, before any request has been submitted to the ring. > >>The request->ctx is foobar and we end up freeing the foobarness. > >> > >>References: https://bugs.freedesktop.org/show_bug.cgi?id=86959 > >>References: https://bugs.freedesktop.org/show_bug.cgi?id=86962 > >>References: https://bugs.freedesktop.org/show_bug.cgi?id=86992 > >>Cc: John Harrison <John.C.Harrison@xxxxxxxxx> > >>Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> I've added this explanation plus the note about which commit introduced the regression to John's patch and merged that one. Thanks for tracking this down. -Daniel > >>--- > >> drivers/gpu/drm/i915/intel_ringbuffer.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >>diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c > >>b/drivers/gpu/drm/i915/intel_ringbuffer.c > >>index 79b4ca5..2c6c6f8 100644 > >>--- a/drivers/gpu/drm/i915/intel_ringbuffer.c > >>+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > >>@@ -2030,7 +2030,7 @@ intel_ring_alloc_request(struct intel_engine_cs > >>*ring) > >> if (ring->outstanding_lazy_request) > >> return 0; > >> - request = kmalloc(sizeof(*request), GFP_KERNEL); > >>+ request = kzalloc(sizeof(*request), GFP_KERNEL); > >> if (request == NULL) > >> return -ENOMEM; > > > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
