From: Matthew Auld matthew.auld@intel.com
commit ecc4d2a52df65479de5e333a9065ed02202a400f upstream.
If we create a rather large userptr object(e.g 1ULL << 32) we might shift past the type-width of num_pages: (int)num_pages << PAGE_SHIFT, resulting in a totally bogus sg_table, which fortunately will eventually manifest as:
gen8_ppgtt_insert_huge:463 GEM_BUG_ON(iter->sg->length < page_size) kernel BUG at drivers/gpu/drm/i915/gt/gen8_ppgtt.c:463!
v2: more unsigned long prefer I915_GTT_PAGE_SIZE
Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl") Signed-off-by: Matthew Auld matthew.auld@intel.com Cc: Chris Wilson chris@chris-wilson.co.uk Reviewed-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Link: https://patchwork.freedesktop.org/patch/msgid/20200117132413.1170563-2-matth... (cherry picked from commit 8e78871bc1e5efec22c950d3fd24ddb63d4ff28a) Signed-off-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 9 +++++---- drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++ 2 files changed, 7 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -427,7 +427,7 @@ struct get_pages_work {
static struct sg_table * __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, - struct page **pvec, int num_pages) + struct page **pvec, unsigned long num_pages) { unsigned int max_segment = i915_sg_segment_size(); struct sg_table *st; @@ -473,9 +473,10 @@ __i915_gem_userptr_get_pages_worker(stru { struct get_pages_work *work = container_of(_work, typeof(*work), work); struct drm_i915_gem_object *obj = work->obj; - const int npages = obj->base.size >> PAGE_SHIFT; + const unsigned long npages = obj->base.size >> PAGE_SHIFT; + unsigned long pinned; struct page **pvec; - int pinned, ret; + int ret;
ret = -ENOMEM; pinned = 0; @@ -578,7 +579,7 @@ __i915_gem_userptr_get_pages_schedule(st
static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj) { - const int num_pages = obj->base.size >> PAGE_SHIFT; + const unsigned long num_pages = obj->base.size >> PAGE_SHIFT; struct mm_struct *mm = obj->userptr.mm->mm; struct page **pvec; struct sg_table *pages; --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -1178,6 +1178,7 @@ gen8_ppgtt_insert_pte(struct i915_ppgtt pd = i915_pd_entry(pdp, gen8_pd_index(idx, 2)); vaddr = kmap_atomic_px(i915_pt_entry(pd, gen8_pd_index(idx, 1))); do { + GEM_BUG_ON(iter->sg->length < I915_GTT_PAGE_SIZE); vaddr[gen8_pd_index(idx, 0)] = pte_encode | iter->dma;
iter->dma += I915_GTT_PAGE_SIZE; @@ -1657,6 +1658,7 @@ static void gen6_ppgtt_insert_entries(st
vaddr = kmap_atomic_px(i915_pt_entry(pd, act_pt)); do { + GEM_BUG_ON(iter.sg->length < I915_GTT_PAGE_SIZE); vaddr[act_pte] = pte_encode | GEN6_PTE_ADDR_ENCODE(iter.dma);
iter.dma += I915_GTT_PAGE_SIZE;