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Message-ID: <1e844f00-fc16-4788-8d90-ebe115eb9313@intel.com>
Date:   Fri, 27 Oct 2023 16:11:31 +0200
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User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] i915/perf: Fix NULL deref bugs with drm_dbg() calls
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To:     Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>,
        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>,
        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
References: <20231027140729.2505993-1-harshit.m.mogalapalli@oracle.com>
From:   Andrzej Hajda <andrzej.hajda@intel.com>
Organization: Intel Technology Poland sp. z o.o. - ul. Slowackiego 173, 80-298
 Gdansk - KRS 101882 - NIP 957-07-52-316
In-Reply-To: <20231027140729.2505993-1-harshit.m.mogalapalli@oracle.com>
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On 27.10.2023 16:07, Harshit Mogalapalli wrote:
> 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>


Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>

Regards
Andrzej

> ---
> 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;
>   	}
>