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Message-ID: <1521811393.27781.2.camel@tzanussi-mobl.amr.corp.intel.com>
Subject: Re: [PATCH] tracing: Fix a potential NULL dereference
From:   Tom Zanussi <tom.zanussi@linux.intel.com>
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        kernel-janitors@vger.kernel.org
Date:   Fri, 23 Mar 2018 08:23:13 -0500
In-Reply-To: <20180323113735.GC28518@mwanda>
References: <20180323113735.GC28518@mwanda>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Dan,

On Fri, 2018-03-23 at 14:37 +0300, Dan Carpenter wrote:
> We forgot to set the error code on this path so we return ERR_PTR(0)
> which is NULL.  It results in a NULL dereference in the caller.
> 
> Fixes: 100719dcef44 ("tracing: Add simple expression support to hist triggers")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 4f027642ceef..a02bc09d765a 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -2776,6 +2776,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
>  		expr->fn = hist_field_plus;
>  		break;
>  	default:
> +		ret = -EINVAL;
>  		goto free;
>  	}
>  

Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>

Thanks for catching this!

Tom