drm/i915: Handle ERESTARTSYS during page fault
During a page fault and rebinding the buffer there exists a window for a
signal to arrive during the i915_wait_request() and trigger a
ERESTARTSYS. This used to be handled by returning SIGBUS and thereby
killing the application. Try 'cairo-perf-trace & cairo-test-suite' and
watch X go boom!
The solution as suggested by H. Peter Anvin is to simply return NOPAGE and
leave the higher layers to spot we did not fill the page and resubmit
the page fault.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
[anholt: Mostly squash it with another commit]
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4755ba4..6129b7b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1200,26 +1200,21 @@
mutex_lock(&dev->struct_mutex);
if (!obj_priv->gtt_space) {
ret = i915_gem_object_bind_to_gtt(obj, 0);
- if (ret) {
- mutex_unlock(&dev->struct_mutex);
- return VM_FAULT_SIGBUS;
- }
+ if (ret)
+ goto unlock;
+
list_add_tail(&obj_priv->list, &dev_priv->mm.inactive_list);
ret = i915_gem_object_set_to_gtt_domain(obj, write);
- if (ret) {
- mutex_unlock(&dev->struct_mutex);
- return VM_FAULT_SIGBUS;
- }
+ if (ret)
+ goto unlock;
}
/* Need a new fence register? */
if (obj_priv->tiling_mode != I915_TILING_NONE) {
ret = i915_gem_object_get_fence_reg(obj);
- if (ret) {
- mutex_unlock(&dev->struct_mutex);
- return VM_FAULT_SIGBUS;
- }
+ if (ret)
+ goto unlock;
}
pfn = ((dev->agp->base + obj_priv->gtt_offset) >> PAGE_SHIFT) +
@@ -1227,18 +1222,18 @@
/* Finally, remap it using the new GTT offset */
ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
-
+unlock:
mutex_unlock(&dev->struct_mutex);
switch (ret) {
+ case 0:
+ case -ERESTARTSYS:
+ return VM_FAULT_NOPAGE;
case -ENOMEM:
case -EAGAIN:
return VM_FAULT_OOM;
- case -EFAULT:
- case -EINVAL:
- return VM_FAULT_SIGBUS;
default:
- return VM_FAULT_NOPAGE;
+ return VM_FAULT_SIGBUS;
}
}
