| Message ID | 20190821142336.21609-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/execlists: Set priority hint prior to submission | expand |
Quoting Chris Wilson (2019-08-21 15:23:36) > Since we now run process_csb() outside of the engine->active.lock, we > can process a CS-event immediately upon our ELSP write. As we currently > inspect the pending queue *after* the ELSP write, there is an > opportunity for a CS-event to update the pending queue before we can > read it, making ourselves chases an invalid pointer. > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111427 > Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock") > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> > --- > drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c > index 44780e7fafec..d42584439f51 100644 > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > @@ -1335,9 +1335,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine) > if (submit) { > *port = execlists_schedule_in(last, port - execlists->pending); > memset(port + 1, 0, (last_port - port) * sizeof(*port)); > - execlists_submit_ports(engine); > execlists->switch_priority_hint = > switch_prio(engine, *execlists->pending); > + execlists_submit_ports(engine); > } else { > ring_set_paused(engine, 0); > } > -- > 2.23.0.rc1 >
Chris Wilson <chris@chris-wilson.co.uk> writes: > Quoting Chris Wilson (2019-08-21 15:23:36) >> Since we now run process_csb() outside of the engine->active.lock, we >> can process a CS-event immediately upon our ELSP write. As we currently >> inspect the pending queue *after* the ELSP write, there is an >> opportunity for a CS-event to update the pending queue before we can >> read it, making ourselves chases an invalid pointer. >> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111427 Enough to make me convinced, Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> >> Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock") >> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> >> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> >> --- >> drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c >> index 44780e7fafec..d42584439f51 100644 >> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c >> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c >> @@ -1335,9 +1335,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine) >> if (submit) { >> *port = execlists_schedule_in(last, port - execlists->pending); >> memset(port + 1, 0, (last_port - port) * sizeof(*port)); >> - execlists_submit_ports(engine); >> execlists->switch_priority_hint = >> switch_prio(engine, *execlists->pending); >> + execlists_submit_ports(engine); >> } else { >> ring_set_paused(engine, 0); >> } >> -- >> 2.23.0.rc1 >>
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 44780e7fafec..d42584439f51 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -1335,9 +1335,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if (submit) { *port = execlists_schedule_in(last, port - execlists->pending); memset(port + 1, 0, (last_port - port) * sizeof(*port)); - execlists_submit_ports(engine); execlists->switch_priority_hint = switch_prio(engine, *execlists->pending); + execlists_submit_ports(engine); } else { ring_set_paused(engine, 0); }
Since we now run process_csb() outside of the engine->active.lock, we can process a CS-event immediately upon our ELSP write. As we currently inspect the pending queue *after* the ELSP write, there is an opportunity for a CS-event to update the pending queue before we can read it, making ourselves chases an invalid pointer. Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> --- drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)