The patch below does not apply to the 4.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 72a6d72c2cd03bba7b70117b63dea83d2de88057 Mon Sep 17 00:00:00 2001
From: Jani Nikula jani.nikula@intel.com Date: Wed, 14 Feb 2018 19:38:40 +0200 Subject: [PATCH] drm/i915/audio: fix check for av_enc_map overflow
Turns out -1 >= ARRAY_SIZE() is always true. Move the bounds check where we know pipe >= 0 and next to the array indexing where it makes most sense.
Fixes: 9965db26ac05 ("drm/i915: Check for fused or unused pipes") Fixes: 0b7029b7e43f ("drm/i915: Check for fused or unused pipes") Cc: stable@vger.kernel.org # v4.10+ Cc: Mika Kahola mika.kahola@intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: intel-gfx@lists.freedesktop.org Reviewed-by: Dhinakaran Pandiyan dhinakaran.pandiyan@intel.com Reviewed-by: Mika Kahola mika.kahola@intel.com Signed-off-by: Jani Nikula jani.nikula@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20180214173840.25360-1-jani.ni... (cherry picked from commit cdb3db8542d854bd678d60cd28861b042e191672) Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c index 522d54fecb53..4a01f62a392d 100644 --- a/drivers/gpu/drm/i915/intel_audio.c +++ b/drivers/gpu/drm/i915/intel_audio.c @@ -779,11 +779,11 @@ static struct intel_encoder *get_saved_enc(struct drm_i915_private *dev_priv, { struct intel_encoder *encoder;
- if (WARN_ON(pipe >= ARRAY_SIZE(dev_priv->av_enc_map))) - return NULL; - /* MST */ if (pipe >= 0) { + if (WARN_ON(pipe >= ARRAY_SIZE(dev_priv->av_enc_map))) + return NULL; + encoder = dev_priv->av_enc_map[pipe]; /* * when bootup, audio driver may not know it is