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 70085ECAAA1 for ; Fri, 28 Oct 2022 16:54:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230231AbiJ1Qy2 (ORCPT ); Fri, 28 Oct 2022 12:54:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55362 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230173AbiJ1QyT (ORCPT ); Fri, 28 Oct 2022 12:54:19 -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 3AB0E224A97; Fri, 28 Oct 2022 09:54:12 -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 5B075623A9; Fri, 28 Oct 2022 16:54:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD04EC433B5; Fri, 28 Oct 2022 16:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666976051; bh=CagHt1YKwrFPw9NQtg1cErC7qHaLnYF/pJpMHFrobgY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YZCvVBy+vDkYlZMf/7/EGEMNXjyy3syl32922bEgQN1M1C36tEVngOnb1IlPUKXaY wSHlRtWrfGlshaalXeNuf9OC1wFi91GF/zFU8FRIIteQwV4XBD8vvDnUdDRZCdBr8Z UluKjSLTSKuB8OA2wNwxNwaSEDwO6iZALGwhE/z3DxBY7cgJBIwCDojZ7A32ChZPm2 1uj+y0rIstBtFf3KBnLeIoxLOljEtHgTP6eP4zlIL9ZUIgHHzAX+BMJ2Riqn8SMFr+ HBlQqwfiL2UeHMVKCe9JZBueFJtrk48+E43D/o+CetvRJwTvVTEGSP+gQ5bAhXJNCH RIBOi4AOUoGYQ== Date: Fri, 28 Oct 2022 22:24:01 +0530 From: Manivannan Sadhasivam To: Qiang Yu Cc: mani@kernel.org, loic.poulain@linaro.org, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, mrana@quicinc.com Subject: Re: [PATCH v2] bus: mhi: host: Fix race between channel preparation and M0 event Message-ID: <20221028165401.GA13880@thinkpad> References: <1665889532-13634-1-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: <1665889532-13634-1-git-send-email-quic_qianyu@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 16, 2022 at 11:05:32AM +0800, Qiang Yu wrote: > There is a race condition where mhi_prepare_channel() updates the > read and write pointers as the base address and in parallel, if > an M0 transition occurs, the tasklet goes ahead and rings > doorbells for all channels with a delta in TRE rings assuming > they are already enabled. This causes a null pointer access. Fix > it by adding a channel enabled check before ringing channel > doorbells. > > Fixes: a6e2e3522f29 "bus: mhi: core: Add support for PM state transitions" > Signed-off-by: Qiang Yu Can you also CC stable list for backporting? Reviewed-by: Manivannan Sadhasivam Thanks, Mani > --- > v1->v2: add Fixes tags > > drivers/bus/mhi/host/pm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c > index 4a42186..0834590 100644 > --- a/drivers/bus/mhi/host/pm.c > +++ b/drivers/bus/mhi/host/pm.c > @@ -301,7 +301,8 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl) > read_lock_irq(&mhi_chan->lock); > > /* Only ring DB if ring is not empty */ > - if (tre_ring->base && tre_ring->wp != tre_ring->rp) > + if (tre_ring->base && tre_ring->wp != tre_ring->rp && > + mhi_chan->ch_state == MHI_CH_STATE_ENABLED) > mhi_ring_chan_db(mhi_cntrl, mhi_chan); > read_unlock_irq(&mhi_chan->lock); > } > -- > 2.7.4 > > -- மணிவண்ணன் சதாசிவம்