From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B8CCC433EF for ; Tue, 17 May 2022 10:08:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245710AbiEQKI1 (ORCPT ); Tue, 17 May 2022 06:08:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343792AbiEQKG4 (ORCPT ); Tue, 17 May 2022 06:06:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F1F312A94; Tue, 17 May 2022 03:06:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C67B761517; Tue, 17 May 2022 10:06:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66FC3C385B8; Tue, 17 May 2022 10:06:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652782003; bh=XlqTAv1FNt4wuVoQs8XijZak1Ap75Io+Uk9IaLscBbc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p/MB8FTB5QtP8P1grjTukVw1xkJhMQfj+g7BVQTw4gcPma8D70mVdfzT3qYWLstfZ 6U3fBQ6QwCjtK11LE/qPXAwVoKGwuA/p3Oo54qCV+stUK4Fisf6KQrjY6rdiG92vxX +YzP6YYAzZJLR8TaJLQD9L50TUxBCcCpCuT59LaU= Date: Tue, 17 May 2022 12:06:39 +0200 From: Greg KH To: Yuanjun Gong Cc: Steven Rostedt , Ingo Molnar , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/1] tracing: fix possible null pointer dereference Message-ID: References: <20220517095723.7426-1-ruc_gongyuanjun@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220517095723.7426-1-ruc_gongyuanjun@163.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 17, 2022 at 05:57:23PM +0800, Yuanjun Gong wrote: > From: Gong Yuanjun > > In hist_trigger_elt_data_alloc(), elt_data is freed by > hist_elt_data_free() if kcalloc fails. > > static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt) > { > ... > elt_data->field_var_str = kcalloc(n_str, sizeof(char *), GFP_KERNEL); > if (!elt_data->field_var_str) { > hist_elt_data_free(elt_data); > return -EINVAL; > } > ...} > > In hist_elt_data_free() the elt_data->field_var_str field should be > checked before dereference. > > Signed-off-by: Gong Yuanjun > --- > kernel/trace/trace_events_hist.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > index 44db5ba9cabb..73177c9f94b2 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -1576,11 +1576,11 @@ static void hist_elt_data_free(struct hist_elt_data *elt_data) > { > unsigned int i; > > - for (i = 0; i < elt_data->n_field_var_str; i++) > - kfree(elt_data->field_var_str[i]); > - > - kfree(elt_data->field_var_str); > - > + if (elt_data->field_var_str) { > + for (i = 0; i < elt_data->n_field_var_str; i++) > + kfree(elt_data->field_var_str[i]); > + kfree(elt_data->field_var_str); > + } > kfree(elt_data->comm); > kfree(elt_data); > } > -- > 2.17.1 > This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.