From 85cc4019f53d436c7a1bd5a175328a6e8a2d0d7a Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 25 May 2020 00:39:00 +0100
Subject: drm/i915/display: Fix early deref of 'dsb'
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Git-commit: 6f081dbfdd4e54d50161c437f2cea176384501d9
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
drivers/gpu/drm/i915/display/intel_dsb.c:177 intel_dsb_reg_write() warn: variable dereferenced before check 'dsb' (see line 175)
Fixes: afeda4f3b1c8 ("drm/i915/dsb: Pre allocate and late cleanup of cmd buffer")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200524233900.25598-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_dsb.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 475106e91fa7..24e6d63e2d47 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -169,15 +169,17 @@ void intel_dsb_indexed_reg_write(const struct intel_crtc_state *crtc_state,
void intel_dsb_reg_write(const struct intel_crtc_state *crtc_state,
i915_reg_t reg, u32 val)
{
- struct intel_dsb *dsb = crtc_state->dsb;
struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
- u32 *buf = dsb->cmd_buf;
+ struct intel_dsb *dsb;
+ u32 *buf;
+ dsb = crtc_state->dsb;
if (!dsb) {
intel_de_write(dev_priv, reg, val);
return;
}
+
buf = dsb->cmd_buf;
if (drm_WARN_ON(&dev_priv->drm, dsb->free_pos >= DSB_BUF_SIZE)) {
drm_dbg_kms(&dev_priv->drm, "DSB buffer overflow\n");
--
2.29.2