| Message ID | 20180719072206.16015-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 19/07/2018 08:22, Chris Wilson wrote: > If we call into the shrinker for direct relcaim inside kmalloc, it will > retire the requests. If we retire the vma->last_active while a new > i915_vma_move_to_active() we can upset the delicate bookkeeping required > for the cache. After the possible invocation of the shrinker, we need to > double check the vma->last_active is still valid. > > Fixes: 8b293eb53a7d ("drm/i915: Track the last-active inside the i915_vma") > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > --- > drivers/gpu/drm/i915/i915_vma.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c > index ed4e0fb558f7..11d834f94220 100644 > --- a/drivers/gpu/drm/i915/i915_vma.c > +++ b/drivers/gpu/drm/i915/i915_vma.c > @@ -942,6 +942,14 @@ static struct i915_gem_active *active_instance(struct i915_vma *vma, u64 idx) > } > > active = kmalloc(sizeof(*active), GFP_KERNEL); > + > + /* kmalloc may retire the vma->last_active request (thanks shrinker)! */ > + if (unlikely(!i915_gem_active_raw(&vma->last_active, > + &vma->vm->i915->drm.struct_mutex))) { > + kfree(active); > + goto out; > + } > + > if (unlikely(!active)) > return ERR_PTR(-ENOMEM); > > Fun! Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Regards, Tvrtko
Quoting Tvrtko Ursulin (2018-07-19 12:18:26) > > On 19/07/2018 08:22, Chris Wilson wrote: > > If we call into the shrinker for direct relcaim inside kmalloc, it will > > retire the requests. If we retire the vma->last_active while a new > > i915_vma_move_to_active() we can upset the delicate bookkeeping required > > for the cache. After the possible invocation of the shrinker, we need to > > double check the vma->last_active is still valid. > > > > Fixes: 8b293eb53a7d ("drm/i915: Track the last-active inside the i915_vma") > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > > --- > > drivers/gpu/drm/i915/i915_vma.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c > > index ed4e0fb558f7..11d834f94220 100644 > > --- a/drivers/gpu/drm/i915/i915_vma.c > > +++ b/drivers/gpu/drm/i915/i915_vma.c > > @@ -942,6 +942,14 @@ static struct i915_gem_active *active_instance(struct i915_vma *vma, u64 idx) > > } > > > > active = kmalloc(sizeof(*active), GFP_KERNEL); > > + > > + /* kmalloc may retire the vma->last_active request (thanks shrinker)! */ > > + if (unlikely(!i915_gem_active_raw(&vma->last_active, > > + &vma->vm->i915->drm.struct_mutex))) { > > + kfree(active); > > + goto out; > > + } > > + > > if (unlikely(!active)) > > return ERR_PTR(-ENOMEM); > > > > > > Fun! > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Pushed to keep CI ticking over. -Chris
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index ed4e0fb558f7..11d834f94220 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -942,6 +942,14 @@ static struct i915_gem_active *active_instance(struct i915_vma *vma, u64 idx) } active = kmalloc(sizeof(*active), GFP_KERNEL); + + /* kmalloc may retire the vma->last_active request (thanks shrinker)! */ + if (unlikely(!i915_gem_active_raw(&vma->last_active, + &vma->vm->i915->drm.struct_mutex))) { + kfree(active); + goto out; + } + if (unlikely(!active)) return ERR_PTR(-ENOMEM);
If we call into the shrinker for direct relcaim inside kmalloc, it will retire the requests. If we retire the vma->last_active while a new i915_vma_move_to_active() we can upset the delicate bookkeeping required for the cache. After the possible invocation of the shrinker, we need to double check the vma->last_active is still valid. Fixes: 8b293eb53a7d ("drm/i915: Track the last-active inside the i915_vma") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> --- drivers/gpu/drm/i915/i915_vma.c | 8 ++++++++ 1 file changed, 8 insertions(+)