From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rasmus Villemoes Subject: [PATCH] drm/i915: Fix comparison bug Date: Mon, 28 Sep 2015 23:08:50 +0200 Message-ID: <1443474531-11560-1-git-send-email-linux@rasmusvillemoes.dk> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Daniel Vetter , Jani Nikula , David Airlie Cc: Rasmus Villemoes , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org ->stolen->start has type u64 aka unsigned long long; relying on the difference (effectively cast to int) for sorting is wrong. It wouldn't be a problem in practice if the values compared are always within INT_MAX of each other (so that the difference is actually representable in an int), but 440fd5283a87 ("drm/mm: Support 4 GiB and larger ranges") strongly suggests that's not the case. Signed-off-by: Rasmus Villemoes --- drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index e3ec9049081f..5207e681a987 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -258,7 +258,11 @@ static int obj_rank_by_stolen(void *priv, struct drm_i915_gem_object *b = container_of(B, struct drm_i915_gem_object, obj_exec_link); - return a->stolen->start - b->stolen->start; + if (a->stolen->start < b->stolen->start) + return -1; + if (a->stolen->start > b->stolen->start) + return 1; + return 0; } static int i915_gem_stolen_list_info(struct seq_file *m, void *data) -- 2.1.3