From ab0d6a141843e0b4b2709dfd37b53468b5452c3a Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 12 Oct 2018 15:02:28 +0100 Subject: [PATCH] drm/i915: Large page offsets for pread/pwrite Handle integer overflow when computing the sub-page length for shmem backed pread/pwrite. Reported-by: Tvrtko Ursulin Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20181012140228.29783-1-chris@chris-wilson.co.uk (cherry picked from commit a5e856a5348f6cd50889d125c40bbeec7328e466) Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/i915/i915_gem.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index db9688d14912..aa3969d52773 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1127,11 +1127,7 @@ i915_gem_shmem_pread(struct drm_i915_gem_object *obj, offset = offset_in_page(args->offset); for (idx = args->offset >> PAGE_SHIFT; remain; idx++) { struct page *page = i915_gem_object_get_page(obj, idx); - int length; - - length = remain; - if (offset + length > PAGE_SIZE) - length = PAGE_SIZE - offset; + unsigned int length = min_t(u64, remain, PAGE_SIZE - offset); ret = shmem_pread(page, offset, length, user_data, page_to_phys(page) & obj_do_bit17_swizzling, @@ -1575,11 +1571,7 @@ i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj, offset = offset_in_page(args->offset); for (idx = args->offset >> PAGE_SHIFT; remain; idx++) { struct page *page = i915_gem_object_get_page(obj, idx); - int length; - - length = remain; - if (offset + length > PAGE_SIZE) - length = PAGE_SIZE - offset; + unsigned int length = min_t(u64, remain, PAGE_SIZE - offset); ret = shmem_pwrite(page, offset, length, user_data, page_to_phys(page) & obj_do_bit17_swizzling, -- 2.30.2