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 07F33C19F29 for ; Fri, 29 Jul 2022 14:26:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237049AbiG2O0T (ORCPT ); Fri, 29 Jul 2022 10:26:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237056AbiG2O0R (ORCPT ); Fri, 29 Jul 2022 10:26:17 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E94DC42ACA; Fri, 29 Jul 2022 07:26:15 -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 sin.source.kernel.org (Postfix) with ESMTPS id 5EEBBCE29C0; Fri, 29 Jul 2022 14:26:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40456C433B5; Fri, 29 Jul 2022 14:26:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659104772; bh=+uMoBAWIxMSyXxcObfO5cph22nMVTb/iovwbfOaC60I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=thrMeuuK2VSrxm0ruqnTHhY8+hQZ4zpezH9G8rUOteC7blIg1D/tpQ2cfpPLhfRWE DLyGP04+rju95e1Y5YIEjnQIVfMco+HTxdfUhU14PFmtQQh1g047x3kh0OD4f6GwrG v9meh8C0T+sXUGmTl6+0qTbj6Q16GfWq/O4OhHZgMLklA8wGnx89N6RwGza6azMDJJ pITNu7roK4QkuvIEuWJtaGAcxoUzho3Ee9weqB/uyMy0OvWXRpA0F0mNYyk2TDvzN2 Orfsr/0dJKcaRTJ1Ng3LwCtnvza8H6A9Iali8xH/wW6+//gl8L/8HlZHFEPI3KJLfd Nk9WijSbKcf4g== Date: Fri, 29 Jul 2022 19:56:05 +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 Subject: Re: [PATCH v3 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler Message-ID: <20220729142605.GB9937@thinkpad> References: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Applied to mhi-next! This patch is targeted for v5.20-rcS. 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. > -- மணிவண்ணன் சதாசிவம்