From patchwork Mon Nov 28 16:15:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Peter X-Patchwork-Id: 13057757 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 9F7DFC4332F for ; Mon, 28 Nov 2022 16:16:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232396AbiK1QQd (ORCPT ); Mon, 28 Nov 2022 11:16:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232761AbiK1QQL (ORCPT ); Mon, 28 Nov 2022 11:16:11 -0500 Received: from wout5-smtp.messagingengine.com (wout5-smtp.messagingengine.com [64.147.123.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59C3EBC1A; Mon, 28 Nov 2022 08:15:38 -0800 (PST) Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.west.internal (Postfix) with ESMTP id 628973200942; Mon, 28 Nov 2022 11:15:35 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute2.internal (MEProxy); Mon, 28 Nov 2022 11:15:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=svenpeter.dev; h=cc:cc:content-transfer-encoding:date:date:from:from :in-reply-to:message-id:mime-version:reply-to:sender:subject :subject:to:to; s=fm1; t=1669652134; x=1669738534; bh=wg7FaKo805 eO+vNPgQ7ztZjMcWXQHDAz6Wy4cpdl6SA=; b=LS5uLeJVdBZuZTtUjOOHkxZRYW Zxzxid+7EuBWTBo86rf+TL/N2F5x6eoDGBDASrMR/VYCSE+XtimVIPI82vmjBCI3 5g3Q7P2nXT+NmLRYfdtSwKyblGaQse+ZIRQ7GHYLYO3do1Fv7Iv2TBSvkfEGCfIW ilCT7xeHvJtg0b62aMsit5Qloni3E130q1VA9l+62hmEdvMhhfKVY0eCrc+jk7Hg OwrX+g9ZaqUlh2ERcVSyvWBWUcnStVqSvPX2Zu36H5lR4YHcfJyoO+F0aGlNd2CP ddwZ8SIxgVUlYPT8SNqZ2Cw1m3ACKn+iC3P4tzkkmusHVMqwARwx5CyH1wuw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :feedback-id:feedback-id:from:from:in-reply-to:message-id :mime-version:reply-to:sender:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t= 1669652134; x=1669738534; bh=wg7FaKo805eO+vNPgQ7ztZjMcWXQHDAz6Wy 4cpdl6SA=; b=b65YMzkTrWpIYtQmR9odiHJDJ7BfHUZN/uWL+F8Aw10cJWGMCxU xBAqjmgl8mAcWdiFba2sRkJGSmdUMkcKdVWRF5kWpOckwD6qFDH5rlA3jbBaYYFO FiKGUCaCm3ofJkuhi2YYtjiNvN4MB4AQDk2vwJOlrdGfxbQG+JjaIuXA0WNhZ/Yq HktPQNh9FVkKdVbh5SQ8EPmPRfIRCy8LUGVBYBu18HHX41Cbomplu81ST0RUKwPl rQLcwwlfpTUJvPh1w/WW09Aw4YJZXzq17QdZayczeFrGhw/LrzqYGR70BW+l67ZF JCuQvyLKbXgRMxfIDtcAFGhSxWr26phVRTg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvgedrjedvgdekkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefhvfevufffkffoggfgsedtkeertdertddtnecuhfhrohhmpefuvhgvnhcurfgv thgvrhcuoehsvhgvnhesshhvvghnphgvthgvrhdruggvvheqnecuggftrfgrthhtvghrnh epleduffeiheeuvedtffevtdeuleeljeduudfgtedtvefhfeffvdfghfejhefgleelnecu vehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepshhvvghnse hsvhgvnhhpvghtvghrrdguvghv X-ME-Proxy: Feedback-ID: i51094778:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 28 Nov 2022 11:15:32 -0500 (EST) From: Sven Peter To: Thinh Nguyen , Greg Kroah-Hartman Cc: Sven Peter , Felipe Balbi , Janne Grunau , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev Subject: [PATCH] usb: dwc3: Fix race between dwc3_set_mode and __dwc3_set_mode Date: Mon, 28 Nov 2022 17:15:26 +0100 Message-Id: <20221128161526.79730-1-sven@svenpeter.dev> X-Mailer: git-send-email 2.30.1 (Apple Git-130) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org dwc->desired_dr_role is changed by dwc3_set_mode inside a spinlock but then read by __dwc3_set_mode outside of that lock. This can lead to a race condition when very quick successive role switch events happen: CPU A dwc3_set_mode(DWC3_GCTL_PRTCAP_HOST) // first role switch event spin_lock_irqsave(&dwc->lock, flags); dwc->desired_dr_role = mode; // DWC3_GCTL_PRTCAP_HOST spin_unlock_irqrestore(&dwc->lock, flags); queue_work(system_freezable_wq, &dwc->drd_work); CPU B __dwc3_set_mode // .... spin_lock_irqsave(&dwc->lock, flags); // desired_dr_role is DWC3_GCTL_PRTCAP_HOST dwc3_set_prtcap(dwc, dwc->desired_dr_role); spin_unlock_irqrestore(&dwc->lock, flags); CPU A dwc3_set_mode(DWC3_GCTL_PRTCAP_DEVICE) // second event spin_lock_irqsave(&dwc->lock, flags); dwc->desired_dr_role = mode; // DWC3_GCTL_PRTCAP_DEVICE spin_unlock_irqrestore(&dwc->lock, flags); CPU B (continues running __dwc3_set_mode) switch (dwc->desired_dr_role) { // DWC3_GCTL_PRTCAP_DEVICE // .... case DWC3_GCTL_PRTCAP_DEVICE: // .... ret = dwc3_gadget_init(dwc); We then have DWC3_GCTL.DWC3_GCTL_PRTCAPDIR = DWC3_GCTL_PRTCAP_HOST and dwc->current_dr_role = DWC3_GCTL_PRTCAP_HOST but initialized the controller in device mode. It's also possible to get into a state where both host and device are intialized at the same time. Fix this race by creating a local copy of desired_dr_role inside __dwc3_set_mode while holding dwc->lock. Fixes: 41ce1456e1db ("usb: dwc3: core: make dwc3_set_mode() work properly") Signed-off-by: Sven Peter Acked-by: Thinh Nguyen --- drivers/usb/dwc3/core.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 1f348bc867c2..fc38a8b13efa 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -122,21 +122,25 @@ static void __dwc3_set_mode(struct work_struct *work) unsigned long flags; int ret; u32 reg; + u32 desired_dr_role; mutex_lock(&dwc->mutex); + spin_lock_irqsave(&dwc->lock, flags); + desired_dr_role = dwc->desired_dr_role; + spin_unlock_irqrestore(&dwc->lock, flags); pm_runtime_get_sync(dwc->dev); if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG) dwc3_otg_update(dwc, 0); - if (!dwc->desired_dr_role) + if (!desired_dr_role) goto out; - if (dwc->desired_dr_role == dwc->current_dr_role) + if (desired_dr_role == dwc->current_dr_role) goto out; - if (dwc->desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev) + if (desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev) goto out; switch (dwc->current_dr_role) { @@ -164,7 +168,7 @@ static void __dwc3_set_mode(struct work_struct *work) */ if (dwc->current_dr_role && ((DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC31, 190A)) && - dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) { + desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) { reg = dwc3_readl(dwc->regs, DWC3_GCTL); reg |= DWC3_GCTL_CORESOFTRESET; dwc3_writel(dwc->regs, DWC3_GCTL, reg); @@ -184,11 +188,11 @@ static void __dwc3_set_mode(struct work_struct *work) spin_lock_irqsave(&dwc->lock, flags); - dwc3_set_prtcap(dwc, dwc->desired_dr_role); + dwc3_set_prtcap(dwc, desired_dr_role); spin_unlock_irqrestore(&dwc->lock, flags); - switch (dwc->desired_dr_role) { + switch (desired_dr_role) { case DWC3_GCTL_PRTCAP_HOST: ret = dwc3_host_init(dwc); if (ret) {