Quoting Joonas Lahtinen (2019-01-07 08:56:56)
Add err goto label and use it when VMA can't be established or changes underneath.
Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
Dubious. All it changes is one branch where the error is forced to -ENOMEM.
Reported-by: Adam Zabrocki adamza@microsoft.com Signed-off-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: stable@vger.kernel.org # v4.0+ Cc: Akash Goel akash.goel@intel.com Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@linux.intel.com Cc: Adam Zabrocki adamza@microsoft.com
drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index f1d594a53978..97cbc0e27e3e 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data, addr = vm_mmap(obj->base.filp, 0, args->size, PROT_READ | PROT_WRITE, MAP_SHARED, args->offset);
if (IS_ERR((void *)addr))goto err;if (args->flags & I915_MMAP_WC) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma;@@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data, else addr = -ENOMEM; up_write(&mm->mmap_sem);
if (IS_ERR((void *)addr))goto err;
The issue still remains that we are returning having called vm_mmap and leaving the vma intact. And we've established above that calling vm_munmap() is a race. -Chris