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drm/msm: Fix NULL deref on bind/probe deferral 

This patch avoids dereferencing msm_host->dev when it is NULL.

If we find ourselves tearing down dsi before calling
(mdp4|mdp5|dpu)_kms_init(), we'll end up in a state where the dev
pointer is NULL and trying to extract priv from it will fail.

This was introduced in a seemingly innocuous commit to ensure the
arguments to msm_gem_put_iova() are correct (even though that
function has been a stub for ~5 years). Correctness FTW! \o/

Fixes: b01884a286b0 drm/msm: use correct aspace pointer in msm_gem_put_iova()
Cc: Daniel Mack <daniel@zonque.org>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
This commit is contained in:
Sean Paul 2018-05-31 14:48:58 -04:00 committed by Rob Clark
parent d14659f5de
commit 74d3a3a707
1 changed files with 11 additions and 1 deletions
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12
drivers/gpu/drm/msm/dsi/dsi_host.c
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@ -1066,8 +1066,18 @@ static int dsi_tx_buf_alloc(struct msm_dsi_host *msm_host, int size)
static void dsi_tx_buf_free(struct msm_dsi_host *msm_host)
{
struct drm_device *dev = msm_host->dev;
struct msm_drm_private *priv = dev->dev_private;
struct msm_drm_private *priv;
/*
* This is possible if we're tearing down before we've had a chance to
* fully initialize. A very real possibility if our probe is deferred,
* in which case we'll hit msm_dsi_host_destroy() without having run
* through the dsi_tx_buf_alloc().
*/
if (!dev)
return;
priv = dev->dev_private;
if (msm_host->tx_gem_obj) {
msm_gem_put_iova(msm_host->tx_gem_obj, priv->kms->aspace);
drm_gem_object_put_unlocked(msm_host->tx_gem_obj);