In intel_wakeref_auto, we use refcount_inc_not_zero to detect the first
use and initialise the timer. On doing so, we have to avoid using
refcount_inc on that zero count as the debug code flags that as an
error:
refcount_t: increment on 0; use-after-free.
Rearrange the code so that if we know the count is 0 and we are
initialising, we explicitly set it to 1.
Fixes: b27e35ae5b18 ("drm/i915: Keep user GGTT alive for a minimum of 250ms")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_wakeref.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index c2dda5a375f0..c25ba1b5e8ba 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -114,11 +114,11 @@ void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout)
if (!refcount_inc_not_zero(&wf->count)) {
spin_lock_irqsave(&wf->lock, flags);
- if (!refcount_read(&wf->count)) {
+ if (!refcount_inc_not_zero(&wf->count)) {
GEM_BUG_ON(wf->wakeref);
wf->wakeref = intel_runtime_pm_get_if_in_use(wf->i915);
+ refcount_set(&wf->count, 1);
}
- refcount_inc(&wf->count);
spin_unlock_irqrestore(&wf->lock, flags);
}
--
2.20.1
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
