| Message ID | 1364297367-17947-1-git-send-email-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 2013-03-26 at 11:29 +0000, Chris Wilson wrote: > There is a minute window for a race between put-fence removing the fence > and for a new transaction by an external party on the GTT mmap. That is > we must zap the mmap prior to removing the fence and not afterwards. > > Fixes regression from > commit 61050808bb019ebea966b7b5bfd357aaf219fb51 > Author: Chris Wilson <chris@chris-wilson.co.uk> > Date: Tue Apr 17 15:31:31 2012 +0100 > > drm/i915: Refactor put_fence() to use the common fence writing routine > > v2: Remember the fence to remove with a local variable (gcc) > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > Cc: stable@vger.kernel.org # regression introduced in v3.5 Reviewed-by: Imre Deak <imre.deak@intel.com>
On Tue, Mar 26, 2013 at 04:25:58PM +0200, Imre Deak wrote: > On Tue, 2013-03-26 at 11:29 +0000, Chris Wilson wrote: > > There is a minute window for a race between put-fence removing the fence > > and for a new transaction by an external party on the GTT mmap. That is > > we must zap the mmap prior to removing the fence and not afterwards. > > > > Fixes regression from > > commit 61050808bb019ebea966b7b5bfd357aaf219fb51 > > Author: Chris Wilson <chris@chris-wilson.co.uk> > > Date: Tue Apr 17 15:31:31 2012 +0100 > > > > drm/i915: Refactor put_fence() to use the common fence writing routine > > > > v2: Remember the fence to remove with a local variable (gcc) > > > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > > Cc: stable@vger.kernel.org # regression introduced in v3.5 > > Reviewed-by: Imre Deak <imre.deak@intel.com> stable rules say "no theoretical races", and I think we don't even have a testcase for this. Hence queued for -next and dropped cc: stable, thanks for the patch. -Daniel
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index a92d431..85b5f56 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2124,11 +2124,11 @@ static void i915_gem_reset_fences(struct drm_device *dev) for (i = 0; i < dev_priv->num_fence_regs; i++) { struct drm_i915_fence_reg *reg = &dev_priv->fence_regs[i]; - i915_gem_write_fence(dev, i, NULL); - if (reg->obj) i915_gem_object_fence_lost(reg->obj); + i915_gem_write_fence(dev, i, NULL); + reg->pin_count = 0; reg->obj = NULL; INIT_LIST_HEAD(®->lru_list); @@ -2751,6 +2751,7 @@ int i915_gem_object_put_fence(struct drm_i915_gem_object *obj) { struct drm_i915_private *dev_priv = obj->base.dev->dev_private; + struct drm_i915_fence_reg *fence; int ret; ret = i915_gem_object_wait_fence(obj); @@ -2760,10 +2761,10 @@ i915_gem_object_put_fence(struct drm_i915_gem_object *obj) if (obj->fence_reg == I915_FENCE_REG_NONE) return 0; - i915_gem_object_update_fence(obj, - &dev_priv->fence_regs[obj->fence_reg], - false); + fence = &dev_priv->fence_regs[obj->fence_reg]; + i915_gem_object_fence_lost(obj); + i915_gem_object_update_fence(obj, fence, false); return 0; }
There is a minute window for a race between put-fence removing the fence and for a new transaction by an external party on the GTT mmap. That is we must zap the mmap prior to removing the fence and not afterwards. Fixes regression from commit 61050808bb019ebea966b7b5bfd357aaf219fb51 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Apr 17 15:31:31 2012 +0100 drm/i915: Refactor put_fence() to use the common fence writing routine v2: Remember the fence to remove with a local variable (gcc) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org # regression introduced in v3.5 --- drivers/gpu/drm/i915/i915_gem.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)