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Date: Fri, 16 Feb 2024 11:44:12 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>, Sumit
 Semwal <sumit.semwal@linaro.org>, Gustavo Padovan <gustavo@padovan.org>,
 Christian =?UTF-8?B?S8O2bmln?= <christian.koenig@amd.com>, Masami Hiramatsu
 <mhiramat@kernel.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
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 linux-trace-kernel@vger.kernel.org, Alex Deucher
 <alexander.deucher@amd.com>, amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH v2 6/6] drm: add drm_mode_atomic_commit event
Message-ID: <20240216114412.1f181ffa@gandalf.local.home>
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On Fri, 16 Feb 2024 17:37:23 +0100
Daniel Vetter <daniel@ffwll.ch> wrote:

> > > @@ -1503,6 +1504,24 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> > >  		drm_mode_object_put(obj);
> > >  	}
> > >  
> > > +	if (trace_drm_mode_atomic_commit_enabled()) {
> > > +		struct drm_crtc_state *crtc_state;
> > > +		struct drm_crtc *crtc;
> > > +		int *crtcs;
> > > +		int i, num_crtcs;
> > > +
> > > +		crtcs = kcalloc(dev->mode_config.num_crtc, sizeof(int),
> > > +				GFP_KERNEL);  
> > 
> > If the above allocation fails, this will cause a NULL kernel dereference.  
> 
> Yeah can't we somehow iterate directly into the trace subsystem? If
> nothing else works I guess just a per-crtc event should do.

You mean like this?

  https://lore.kernel.org/all/20240216105934.7b81eae9@gandalf.local.home/

;-)

-- Steve