From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A7BF16C6B0; Mon, 19 Aug 2024 13:28:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724074084; cv=none; b=TAxcbImtI6xzKJ33suUq9TVqLK8CWx0UBvz5GMuuzIgnpMYzsByn6np9Grav3TuGvyv6MZ08qT7APGUIQc2ytrjiBT0xGNJZKsolqSHz1pouoQmzLGcvVoWYsg5K8/75CNns1iyytKffdyiRF52zIh7l9BowKYWmuvxEgx4I86I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724074084; c=relaxed/simple; bh=zk60qwCpwoyAMlYOMZRUAKQf+lxHInyJ2uctVdPTy30=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EQorvR5DTdypl9NWNLDO5PGPJt3eNrTeFpNcO6CBClkCvQXsJGHQWqCE47BMTlq6MsPDIf6HHb35f/0GGRp6LHiXeNCHkUnUaAIW+sBCheTrhQs0MyAgmuF3NPivWO3HYbfSEonf3+6IutaDsAMlHYah8fcBjMeX5zVFMP3lQYo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=e6C9r52j; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="e6C9r52j" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724074082; x=1755610082; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=zk60qwCpwoyAMlYOMZRUAKQf+lxHInyJ2uctVdPTy30=; b=e6C9r52jyvLncuvRfn+jc0vbNm9Fg9lyoQJk/T6goN2/7VsGa2XY0I+F /BmzRrLSIMXHExmrshvoOLO6v0qrVYWjVbIs8q4A9jJzSPQr0IaDCMvDj BLaXLSUa4tl9L/AZfzNQeZuQWIhH6MQaU0jJl/NMmJgYAjD937QiUEfAm 7DIQVYbnGwdOpP0WVgCvzA0THALr7APhm6o4UH081R2OHcrB3LJ8UjJVu ccNJjf2+1D1dOpgiXMcpx3cHlaieYnStR1AokRUBJIcSd0Q8A7gcP5isg KRdjSvfql5hPan1UBEqXn/0Zw4SUilhcS17cXscnfq/gjPG/nY6RKNjyC A==; X-CSE-ConnectionGUID: bEo6rmKFQbKfXQoyL4jgjw== X-CSE-MsgGUID: y8nWWc47SZiHsvEeggDarg== X-IronPort-AV: E=McAfee;i="6700,10204,11169"; a="21866901" X-IronPort-AV: E=Sophos;i="6.10,159,1719903600"; d="scan'208";a="21866901" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2024 06:28:02 -0700 X-CSE-ConnectionGUID: vZM+LOvuQ0WfPr3xuIGxkQ== X-CSE-MsgGUID: fDw++BBnTASU66FSB+U9wg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,159,1719903600"; d="scan'208";a="60072748" Received: from kuha.fi.intel.com ([10.237.72.185]) by fmviesa007.fm.intel.com with SMTP; 19 Aug 2024 06:27:57 -0700 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Mon, 19 Aug 2024 16:27:56 +0300 Date: Mon, 19 Aug 2024 16:27:56 +0300 From: Heikki Krogerus To: Bjorn Andersson Cc: Sebastian Reichel , Bjorn Andersson , Konrad Dybcio , Greg Kroah-Hartman , Neil Armstrong , Johan Hovold , Chris Lew , Dmitry Baryshkov , Stephen Boyd , Amit Pundir , linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 2/3] usb: typec: ucsi: Move unregister out of atomic section Message-ID: References: <20240818-pmic-glink-v6-11-races-v1-0-f87c577e0bc9@quicinc.com> <20240818-pmic-glink-v6-11-races-v1-2-f87c577e0bc9@quicinc.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240818-pmic-glink-v6-11-races-v1-2-f87c577e0bc9@quicinc.com> On Sun, Aug 18, 2024 at 04:17:38PM -0700, Bjorn Andersson wrote: > Commit 'caa855189104 ("soc: qcom: pmic_glink: Fix race during > initialization")' moved the pmic_glink client list under a spinlock, as > it is accessed by the rpmsg/glink callback, which in turn is invoked > from IRQ context. > > This means that ucsi_unregister() is now called from IRQ context, which > isn't feasible as it's expecting a sleepable context. An effort is under > way to get GLINK to invoke its callbacks in a sleepable context, but > until then lets schedule the unregistration. > > A side effect of this is that ucsi_unregister() can now happen > after the remote processor, and thereby the communication link with it, is > gone. pmic_glink_send() is amended with a check to avoid the resulting > NULL pointer dereference, but it becomes expecting to see a failing send > upon shutting down the remote processor (e.g. during a restart following > a firmware crash): > > ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5 > > Fixes: caa855189104 ("soc: qcom: pmic_glink: Fix race during initialization") > Cc: stable@vger.kernel.org > Signed-off-by: Bjorn Andersson Reviewed-by: Heikki Krogerus > --- > drivers/soc/qcom/pmic_glink.c | 10 +++++++++- > drivers/usb/typec/ucsi/ucsi_glink.c | 28 +++++++++++++++++++++++----- > 2 files changed, 32 insertions(+), 6 deletions(-) > > diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c > index 58ec91767d79..e4747f1d3da5 100644 > --- a/drivers/soc/qcom/pmic_glink.c > +++ b/drivers/soc/qcom/pmic_glink.c > @@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_register_client); > int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len) > { > struct pmic_glink *pg = client->pg; > + int ret; > > - return rpmsg_send(pg->ept, data, len); > + mutex_lock(&pg->state_lock); > + if (!pg->ept) > + ret = -ECONNRESET; > + else > + ret = rpmsg_send(pg->ept, data, len); > + mutex_unlock(&pg->state_lock); > + > + return ret; > } > EXPORT_SYMBOL_GPL(pmic_glink_send); > > diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c > index ac53a81c2a81..a33056eec83d 100644 > --- a/drivers/usb/typec/ucsi/ucsi_glink.c > +++ b/drivers/usb/typec/ucsi/ucsi_glink.c > @@ -68,6 +68,9 @@ struct pmic_glink_ucsi { > > struct work_struct notify_work; > struct work_struct register_work; > + spinlock_t state_lock; > + unsigned int pdr_state; > + unsigned int new_pdr_state; > > u8 read_buf[UCSI_BUF_SIZE]; > }; > @@ -244,8 +247,22 @@ static void pmic_glink_ucsi_notify(struct work_struct *work) > static void pmic_glink_ucsi_register(struct work_struct *work) > { > struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work); > + unsigned long flags; > + unsigned int new_state; > + > + spin_lock_irqsave(&ucsi->state_lock, flags); > + new_state = ucsi->new_pdr_state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + > + if (ucsi->pdr_state != SERVREG_SERVICE_STATE_UP) { > + if (new_state == SERVREG_SERVICE_STATE_UP) > + ucsi_register(ucsi->ucsi); > + } else { > + if (new_state == SERVREG_SERVICE_STATE_DOWN) > + ucsi_unregister(ucsi->ucsi); > + } > > - ucsi_register(ucsi->ucsi); > + ucsi->pdr_state = new_state; > } > > static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) > @@ -269,11 +286,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) > static void pmic_glink_ucsi_pdr_notify(void *priv, int state) > { > struct pmic_glink_ucsi *ucsi = priv; > + unsigned long flags; > > - if (state == SERVREG_SERVICE_STATE_UP) > - schedule_work(&ucsi->register_work); > - else if (state == SERVREG_SERVICE_STATE_DOWN) > - ucsi_unregister(ucsi->ucsi); > + spin_lock_irqsave(&ucsi->state_lock, flags); > + ucsi->new_pdr_state = state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + schedule_work(&ucsi->register_work); > } > > static void pmic_glink_ucsi_destroy(void *data) > > -- > 2.34.1 -- heikki