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@xxxxxxxxxxxxxxxxxx> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> --- 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@xxxxxxxxx> Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
