[PATCH 4.19 108/190] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

Greg Kroah-Hartman
2019-09-13T13:16:17Z

[ Upstream commit ebfb6977801da521d8d5d752d373a187e2a2b9b3 ]

Add err goto label and use it when VMA can't be established or changes
underneath.

v2:
- Dropping Fixes: as it's indeed impossible to race an object to the
error address. (Chris)
v3:
- Use IS_ERR_VALUE (Chris)

Reported-by: Adam Zabrocki <adamza@microsoft.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Adam Zabrocki <adamza@microsoft.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> #v2
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190207085454.10598-2-joonas.lahtinen@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 e81abd468a15d..9634d3adb8d01 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1881,6 +1881,9 @@ 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_VALUE(addr))
+ goto err;
+
if (args->flags & I915_MMAP_WC) {
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
@@ -1896,17 +1899,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
else
addr = -ENOMEM;
up_write(&mm->mmap_sem);
+ if (IS_ERR_VALUE(addr))
+ goto err;

/* This may race, but that's ok, it only gets set */
WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
}
i915_gem_object_put(obj);
- if (IS_ERR((void *)addr))
- return addr;

args->addr_ptr = (uint64_t) addr;

return 0;
+
+err:
+ i915_gem_object_put(obj);
+
+ return addr;
}

static unsigned int tile_row_pages(struct drm_i915_gem_object *obj)
--
2.20.1