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 0A5A7C433EF for ; Tue, 26 Jul 2022 08:06:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238190AbiGZIGx (ORCPT ); Tue, 26 Jul 2022 04:06:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238400AbiGZIGr (ORCPT ); Tue, 26 Jul 2022 04:06:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 958502DAA4; Tue, 26 Jul 2022 01:06:45 -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 E90A2614D7; Tue, 26 Jul 2022 08:06:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5999C36AE5; Tue, 26 Jul 2022 08:06:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658822804; bh=AuSXlGXkPcDkuhy4cIR2vtHDpg/jer5nbJzf7kZ8fcg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RCCcqAC2M4GslsUvGs5C1x4+/2G3a3w3bEuNTAsrTHtM9sH6pN3U++bWLhLWuMidi zyAWadDpmrSgL3lkX4NJrljlmQzjsXQeXb0RJ3rAOeqYMNes0+jhfEafI+YcAXukfV Cb+GkC9NUF1my0VIXuNvFzzLy4cZ13h4wg8V6FlXp3svHe1+70jkp9K9CouDzXWvoE 82aN/TJUjy7zVRKWMxIiI5Ke8jDreKJX0p7iWbhun3lHl67Do4z9E+1wMqXTfhLOS2 W2LC0sskVe1kYmIVXoAMYvs01+RLxH6s7V76IQE4clsmRJLHP1AwakVhf3OnsjtjV9 NQF6jaLu8+bCA== Date: Tue, 26 Jul 2022 13:36:36 +0530 From: Manivannan Sadhasivam To: Qiang Yu Cc: quic_hemantk@quicinc.com, loic.poulain@linaro.org, quic_jhugo@quicinc.com, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, ath11k@lists.infradead.org, kvalo@kernel.org Subject: Re: [PATCH v3 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler Message-ID: <20220726080636.GE5522@workstation> References: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +ath11k, Kalle On Fri, Jul 22, 2022 at 11:17:18AM +0800, Qiang Yu wrote: > The irq handler for a shared IRQ ought to be prepared for running > even now it's being freed. So let's check the pointer used by > mhi_irq_handler to avoid null pointer access since it is probably > released before freeing IRQ. > > Signed-off-by: Qiang Yu Reviewed-by: Manivannan Sadhasivam Thanks, Mani > --- > v2->v3: add comments > v1->v2: change dev_err to dev_dbg > > drivers/bus/mhi/host/main.c | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c > index f3aef77a..df0fbfe 100644 > --- a/drivers/bus/mhi/host/main.c > +++ b/drivers/bus/mhi/host/main.c > @@ -430,12 +430,25 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) > { > struct mhi_event *mhi_event = dev; > struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; > - struct mhi_event_ctxt *er_ctxt = > - &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index]; > + struct mhi_event_ctxt *er_ctxt; > struct mhi_ring *ev_ring = &mhi_event->ring; > - dma_addr_t ptr = le64_to_cpu(er_ctxt->rp); > + dma_addr_t ptr; > void *dev_rp; > > + /* > + * If CONFIG_DEBUG_SHIRQ is set, the IRQ handler will get invoked during __free_irq() > + * and by that time mhi_ctxt() would've freed. So check for the existence of mhi_ctxt > + * before handling the IRQs. > + */ > + if (!mhi_cntrl->mhi_ctxt) { > + dev_dbg(&mhi_cntrl->mhi_dev->dev, > + "mhi_ctxt has been freed\n"); > + return IRQ_HANDLED; > + } > + > + er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index]; > + ptr = le64_to_cpu(er_ctxt->rp); > + > if (!is_valid_ring_ptr(ev_ring, ptr)) { > dev_err(&mhi_cntrl->mhi_dev->dev, > "Event ring rp points outside of the event ring\n"); > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project. >