From patchwork Fri Jul 22 03:17:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qiang Yu X-Patchwork-Id: 593205 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 8F723C43334 for ; Fri, 22 Jul 2022 03:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234162AbiGVDRk (ORCPT ); Thu, 21 Jul 2022 23:17:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233967AbiGVDRf (ORCPT ); Thu, 21 Jul 2022 23:17:35 -0400 Received: from alexa-out-sd-02.qualcomm.com (alexa-out-sd-02.qualcomm.com [199.106.114.39]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D5A987F70; Thu, 21 Jul 2022 20:17:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1658459854; x=1689995854; h=from:to:cc:subject:date:message-id:mime-version; bh=gEDWsiz11GhB4pUHw7t4kAgF8/TF7yajo/DSLMNkb3Y=; b=Kh1wqlnBescfCivTjqIgDmSRvPi7HDS2XotxTmAfpMzRYwGEqRR2V3JY BnagGAOjPF7AWubTNOMQbxPxh/TcbO1ThJX6bjJDlxmx+UWYUJsLF3Ybk Ffk7u9Epd2qFXDrZiP+UEPwhDalGkBjvBkaOWhpjvyws4C3IIxqVl4yyg o=; Received: from unknown (HELO ironmsg02-sd.qualcomm.com) ([10.53.140.142]) by alexa-out-sd-02.qualcomm.com with ESMTP; 21 Jul 2022 20:17:33 -0700 X-QCInternal: smtphost Received: from unknown (HELO nasanex01a.na.qualcomm.com) ([10.52.223.231]) by ironmsg02-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jul 2022 20:17:33 -0700 Received: from cbsp-sh-gv.qualcomm.com (10.80.80.8) by nasanex01a.na.qualcomm.com (10.52.223.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Thu, 21 Jul 2022 20:17:31 -0700 From: Qiang Yu To: , , , CC: , , , , Qiang Yu Subject: [PATCH v3 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler Date: Fri, 22 Jul 2022 11:17:18 +0800 Message-ID: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nasanex01a.na.qualcomm.com (10.52.223.231) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 Tested-by: Kalle Valo --- 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");