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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2041C433E0 for ; Tue, 16 Mar 2021 06:17:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC6BF6520B for ; Tue, 16 Mar 2021 06:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235752AbhCPGRQ (ORCPT ); Tue, 16 Mar 2021 02:17:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232816AbhCPGQv (ORCPT ); Tue, 16 Mar 2021 02:16:51 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D89E5C061756 for ; Mon, 15 Mar 2021 23:16:51 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id v14so14993191pgq.2 for ; Mon, 15 Mar 2021 23:16:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=7h2yXhFof54YGjMWDbaJozcTXrsSdqE/dyDBMyKGJ5Y=; b=QbzsDrIYg7eHAgh4pGB4AAmMnT1WVG9zZnAMCz9/f+XPsbeRlJvMiFQl0L3v3X0d+d 6DllluutMlvH72r6ur/Wj4Mcl2cusydCWFJzfajjR5MUeK0gAYPoj3dGbCznqXe7potY j9iJhkostX06gSzSk2SvjNVshl8gTDHdVSmmn3i8XZnK3Tf+QlkgwsyInEwIZDDiOw/M IUYaJjw6YC2slzc+QiVQKeyDGlFcPq0eSIrJkQxoaa6bDtOwhbLm43yq+VLOyGItARVG 9rn/gf5sZkstLMzwlcUuyFy1agBrcZRRK/RxcpENwQsVhJmMAnZjbGCg8mLp5rxXPKhk k1Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=7h2yXhFof54YGjMWDbaJozcTXrsSdqE/dyDBMyKGJ5Y=; b=FsCFPxstMrbKS6LlVnLaWa8+CK8EVBzKvJJQZPHbVuofyIFGIz3qZQ8BOu4sdnn8mM LL4udrtvxgLpT5TVwwAgNV3LpC1O1JQ7YMnOXBrPoaBdsmVW5dz5NIdS10vtQ8TYIIAw uD56uzCFHfTGDBtiyOhN09QDIY7sZbY6Ib9sWAlQbbXrY4+Snp2J9gPgpb2SG2UxIvL5 aFvirk1N3BMbyu0s5B0/LsrgjZ7KkpzB/6xMLuwBzg9P7Xn2OOaRd0H+YBGjB8bJoMS8 OapuzFJS7Ze5VL5NkpWtnk32KKqO4A+23RaZZHEYuoDiYWYHCf150vGrRxEhaQ28yCny cKaw== X-Gm-Message-State: AOAM5338zIAjYtJccZ6dxxsHOHk4QxBwRN9iAsb1jRDKjWwwq/Sgunc4 fW9a4V6HaApZpPkytl3mWkuj X-Google-Smtp-Source: ABdhPJzbu3uIbNoqRjsPpFLMtZloQO2Rh2lDCvmacc2qKHwbpCQkpacd7bG1V4Ba8EAiFg3WpqBMvw== X-Received: by 2002:a63:e22:: with SMTP id d34mr2552544pgl.264.1615875411306; Mon, 15 Mar 2021 23:16:51 -0700 (PDT) Received: from thinkpad ([103.66.79.72]) by smtp.gmail.com with ESMTPSA id gk12sm1545108pjb.44.2021.03.15.23.16.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Mar 2021 23:16:50 -0700 (PDT) Date: Tue, 16 Mar 2021 11:46:46 +0530 From: Manivannan Sadhasivam To: Jeffrey Hugo Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] bus: mhi: core: Check state before processing power_down Message-ID: <20210316061646.GH1798@thinkpad> References: <1615409365-8165-1-git-send-email-jhugo@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1615409365-8165-1-git-send-email-jhugo@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 10, 2021 at 01:49:25PM -0700, Jeffrey Hugo wrote: > We cannot process a power_down if the power state is DISABLED. There is > no valid mhi_ctxt in that case, so attepting to process the power_down > will likely result in a null pointer dereference. If the power state is > DISABLED, there is nothing to do anyways, so just bail early. > > Signed-off-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam Thanks, Mani > --- > > v3: Move the pm_lock use up > v2: Fix subject and tweak the locking to avoid needless lock/unlock/relock > > drivers/bus/mhi/core/pm.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index 414da4f..ea62549 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -1149,6 +1149,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > mhi_deinit_dev_ctxt(mhi_cntrl); > > error_dev_ctxt: > + mhi_cntrl->pm_state = MHI_PM_DISABLE; > mutex_unlock(&mhi_cntrl->pm_mutex); > > return ret; > @@ -1160,12 +1161,19 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > enum mhi_pm_state cur_state, transition_state; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > > + mutex_lock(&mhi_cntrl->pm_mutex); > + write_lock_irq(&mhi_cntrl->pm_lock); > + cur_state = mhi_cntrl->pm_state; > + if (cur_state == MHI_PM_DISABLE) { > + write_unlock_irq(&mhi_cntrl->pm_lock); > + mutex_unlock(&mhi_cntrl->pm_mutex); > + return; /* Already powered down */ > + } > + > /* If it's not a graceful shutdown, force MHI to linkdown state */ > transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS : > MHI_PM_LD_ERR_FATAL_DETECT; > > - mutex_lock(&mhi_cntrl->pm_mutex); > - write_lock_irq(&mhi_cntrl->pm_lock); > cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); > if (cur_state != transition_state) { > dev_err(dev, "Failed to move to state: %s from: %s\n", > -- > Qualcomm Technologies, Inc. is a member of the > Code Aurora Forum, a Linux Foundation Collaborative Project. >