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 AD2A1C54EBE for ; Mon, 16 Jan 2023 16:06:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232110AbjAPQGu (ORCPT ); Mon, 16 Jan 2023 11:06:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232243AbjAPQGO (ORCPT ); Mon, 16 Jan 2023 11:06:14 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3ED6B23D92 for ; Mon, 16 Jan 2023 08:04:36 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id ED2B3B81060 for ; Mon, 16 Jan 2023 16:04:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52588C433EF; Mon, 16 Jan 2023 16:04:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885073; bh=3xteQ9jQKhn+tRgWq/xoHRCBtd/+9YToqzMGlIwpfdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XybnsorPOqsbq16oZ9lprjlQ9annWuELYuC6U2S6kIgQTgOp8fiovcaURn/lZ9pdM 9QdKiA0QY8IoDCpVjPI/093VpAZNRBGUfhwJ8A9HZHGHDjZWDtzxrDwoDCt5oc3Q/s xUkQ+JADhHzmA0GL4xH5l+JQCgYx/t2xZehNo3c4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qiang Yu , Manivannan Sadhasivam , Manivannan Sadhasivam , Sasha Levin Subject: [PATCH 5.15 35/86] bus: mhi: host: Fix race between channel preparation and M0 event Date: Mon, 16 Jan 2023 16:51:09 +0100 Message-Id: <20230116154748.547464918@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154747.036911298@linuxfoundation.org> References: <20230116154747.036911298@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qiang Yu [ Upstream commit 869a99907faea6d1835b0bd0d0422ae3519c6ea9 ] 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. Cc: stable@vger.kernel.org # 5.19 Fixes: a6e2e3522f29 "bus: mhi: core: Add support for PM state transitions" Signed-off-by: Qiang Yu Reviewed-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/1665889532-13634-1-git-send-email-quic_qianyu@quicinc.com [mani: CCed stable list] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Sasha Levin --- drivers/bus/mhi/core/pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 1020268a075a..1a87b9c6c2f8 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -297,7 +297,8 @@ 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); } -- 2.35.1