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@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 9 +++++----
drivers/gpu/drm/i915/gt/gen6_ppgtt.c | 1 +
drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 1 +
3 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index b64b0f383a56..a74d4ac6a39f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -403,7 +403,7 @@ 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;
@@ -449,9 +449,10 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
{
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;
@@ -559,7 +560,7 @@ __i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj)
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;
diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
index f10b2c41571c..f4fec7eb4064 100644
--- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
@@ -131,6 +131,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
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;
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index 077b8f7cf6cb..4d1de2d97d5c 100644
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -379,6 +379,7 @@ gen8_ppgtt_insert_pte(struct i915_ppgtt *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;
--
2.20.1
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