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From:   Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To:     Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>,
        Lionel Landwerlin <lionel.g.landwerlin@intel.com>,
        Matt Roper <matthew.d.roper@intel.com>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Cc:     dan.carpenter@linaro.org, kernel-janitors@vger.kernel.org,
        error27@gmail.com, harshit.m.mogalapalli@oracle.com
Subject: [PATCH] i915/perf: Fix NULL deref bugs with drm_dbg() calls
Date:   Fri, 27 Oct 2023 07:07:28 -0700
Message-ID: <20231027140729.2505993-1-harshit.m.mogalapalli@oracle.com>
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When i915 perf interface is not available dereferencing it will lead to
NULL dereferences.

Fix this by using DRM_DEBUG() which the scenario before the commit in
the Fixes tag.

Fixes: 2fec539112e8 ("i915/perf: Replace DRM_DEBUG with driver specific drm_dbg call")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is found using smatch(static analysis tool), only compile tested.
---
 drivers/gpu/drm/i915/i915_perf.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 2f3ecd7d4804..bb48c96b7950 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -4228,8 +4228,7 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
 	int ret;
 
 	if (!perf->i915) {
-		drm_dbg(&perf->i915->drm,
-			"i915 perf interface not available for this system\n");
+		DRM_DEBUG("i915 perf interface not available for this system\n");
 		return -ENOTSUPP;
 	}
 
@@ -4608,8 +4607,7 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
 	int err, id;
 
 	if (!perf->i915) {
-		drm_dbg(&perf->i915->drm,
-			"i915 perf interface not available for this system\n");
+		DRM_DEBUG("i915 perf interface not available for this system\n");
 		return -ENOTSUPP;
 	}
 
@@ -4774,8 +4772,7 @@ int i915_perf_remove_config_ioctl(struct drm_device *dev, void *data,
 	int ret;
 
 	if (!perf->i915) {
-		drm_dbg(&perf->i915->drm,
-			"i915 perf interface not available for this system\n");
+		DRM_DEBUG("i915 perf interface not available for this system\n");
 		return -ENOTSUPP;
 	}
 
-- 
2.39.3