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Message-ID: <934b0ae20a78f87b556d0dfd150282f033bc1483.camel@kernel.org>
Subject: Re: [PATCH] tracing / histogram: Fix NULL pointer dereference on
 strcmp() on NULL event name
From:   Tom Zanussi <zanussi@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Masami Hiramatsu <mhiramat@kernel.org>
Date:   Wed, 11 Aug 2021 10:29:10 -0500
In-Reply-To: <20210811103522.0cac5f1a@oasis.local.home>
References: <20210808003011.4037f8d0@oasis.local.home>
         <20210811103522.0cac5f1a@oasis.local.home>
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Hi Steve,

On Wed, 2021-08-11 at 10:35 -0400, Steven Rostedt wrote:
> On Sun, 8 Aug 2021 00:30:11 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > diff --git a/kernel/trace/trace_events_hist.c
> > b/kernel/trace/trace_events_hist.c
> > index 949ef09dc537..a48aa2a2875b 100644
> > --- a/kernel/trace/trace_events_hist.c
> > +++ b/kernel/trace/trace_events_hist.c
> > @@ -3430,6 +3430,8 @@ trace_action_create_field_var(struct
> > hist_trigger_data *hist_data,
> >  			event = data->match_data.event;
> >  		}
> >  
> > +		if (!event)
> > +			goto free;
> >  		/*
> >  		 * At this point, we're looking at a field on another
> >  		 * event.  Because we can't modify a hist trigger on
> > -- 
> 
> Tom,
> 
> Is this OK? I'm going to start running this through my tests and when
> it's done, I'm going to send it off to Linus.

Sorry, missed this one.

But yeah, this fixes the problem, thanks!

Reviewed-by: Tom Zanussi <zanussi@kernel.org>


> 
> -- Steve