From 1f2b10131f83f7caa67bf1273cec126b4283015d Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 12 Mar 2010 19:52:55 +0000 Subject: [PATCH] drm/i915: Avoid NULL deref in get_pages() unwind after error. Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=15527 NULL pointer dereference in i915_gem_object_save_bit_17_swizzle BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] i915_gem_object_save_bit_17_swizzle+0x5b/0xc0 [i915] Call Trace: [] ? i915_gem_object_put_pages+0x125/0x150 [i915] [] ? i915_gem_object_get_pages+0xf1/0x110 [i915] [] ? i915_gem_object_bind_to_gtt+0xb8/0x2a0 [i915] [] ? drm_mm_get_block_generic+0x4d/0x180 [] ? i915_gem_mmap_gtt_ioctl+0x16d/0x240 [i915] [] ? i915_gem_madvise_ioctl+0x86/0x120 [i915] Signed-off-by: Chris Wilson Reported-by: maciej.rutecki@gmail.com Cc: stable@kernel.org Reviewed-by: Eric Anholt Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/i915_gem.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 134973f77069..933e865a8929 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1466,9 +1466,6 @@ i915_gem_object_put_pages(struct drm_gem_object *obj) obj_priv->dirty = 0; for (i = 0; i < page_count; i++) { - if (obj_priv->pages[i] == NULL) - break; - if (obj_priv->dirty) set_page_dirty(obj_priv->pages[i]); @@ -2251,7 +2248,6 @@ i915_gem_object_get_pages(struct drm_gem_object *obj, struct address_space *mapping; struct inode *inode; struct page *page; - int ret; if (obj_priv->pages_refcount++ != 0) return 0; @@ -2274,11 +2270,9 @@ i915_gem_object_get_pages(struct drm_gem_object *obj, mapping_gfp_mask (mapping) | __GFP_COLD | gfpmask); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - i915_gem_object_put_pages(obj); - return ret; - } + if (IS_ERR(page)) + goto err_pages; + obj_priv->pages[i] = page; } @@ -2286,6 +2280,15 @@ i915_gem_object_get_pages(struct drm_gem_object *obj, i915_gem_object_do_bit_17_swizzle(obj); return 0; + +err_pages: + while (i--) + page_cache_release(obj_priv->pages[i]); + + drm_free_large(obj_priv->pages); + obj_priv->pages = NULL; + obj_priv->pages_refcount--; + return PTR_ERR(page); } static void sandybridge_write_fence_reg(struct drm_i915_fence_reg *reg) -- 2.30.2