From: Sean Paul Date: Thu, 31 May 2018 18:48:58 +0000 (-0400) Subject: drm/msm: Fix NULL deref on bind/probe deferral X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=74d3a3a70775de356b96b5461c3a204a51496fb3;p=openwrt%2Fstaging%2Fblogic.git 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 Cc: Rob Clark Signed-off-by: Sean Paul Signed-off-by: Rob Clark --- diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index b916f464f4ec..2f1a2780658a 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -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);