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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b5-20020aa78ec5000000b0063b8935bcbasi4644349pfr.310.2023.05.31.20.28.50; Wed, 31 May 2023 20:29:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=Ut1jhxjP; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231127AbjFADLO (ORCPT + 99 others); Wed, 31 May 2023 23:11:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231163AbjFADKq (ORCPT ); Wed, 31 May 2023 23:10:46 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B13B319B for ; Wed, 31 May 2023 20:10:34 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-568960f4596so5484757b3.1 for ; Wed, 31 May 2023 20:10:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685589034; x=1688181034; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=EGZ1WhiGHCBCj3GPYMR/3aCWSuzXHxHhjnfYSDvHWIM=; b=Ut1jhxjPDA77sh3qS7SA72NB9IC3OxXHQ0XqXZyNjQcu/porBvqfNL1HG22Yi15nx+ 0hhLhORj1tlpBHnuaLNzwMJzDJwhFL8xsFH6mxfzFPMWsZvT69afritl0LK+e1JL6Nee JyqDe+CthVx5KBzuIU21AymMJico/HZswFRGbVY0DBBrLeUVUx6hkvnUo+P+zQWMvFsv IbdfZXSZgXnC9bG6YMkl+6FghiULoKhEjgonaDWLJ+aVshKZgArA4OAL5qHfeAXnJ8c2 rzci4H2fUVr8bJhyQKjWmr/b6pE5bgMtwf6Mkt7dGfFtnha/MtVGkCFNCI9FAM8OxFyY LkfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685589034; x=1688181034; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EGZ1WhiGHCBCj3GPYMR/3aCWSuzXHxHhjnfYSDvHWIM=; b=JON+2KHRxFcgLec4PdqWeBpc1q8KivmrtwjQME6WK6X/vMbrjiC6vC79HPfV3ydSnc 2lZjEARym+knP1qbmTNVZbzEooZ6CBW5dhYA/he9kmhYpfaHpC1n08JMunom4LNnv8JY xQX6bnZ6iYS8UMaXUVLv56q+nd6QC53OJotP+UX7yB+3AWd+E69allcTbvKBM17cJi1g o+lIfxR26vjgCgAHitd9Fh/kM+7kRqCH4CTGyCSjAiYpzgS7JbS9faPoSHzQAptgqeTm XmaHWpEkETA2nby3qt0zDQHEJ+ix2vC0TuImC94hnSESZU4nF6QK1BdadlMgpt4/7DEe ZT1g== X-Gm-Message-State: AC+VfDy0M6O1PCybqmYzQteM+83Q3xyi1Gxo5Mjza9iw0XAhh95XW+he ZEDb2AtmS2eiT7QAjfQdI6zr0hzh7LM= X-Received: from badhri.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:6442]) (user=badhri job=sendgmr) by 2002:a81:b245:0:b0:55d:8472:4597 with SMTP id q66-20020a81b245000000b0055d84724597mr4559089ywh.10.1685589033907; Wed, 31 May 2023 20:10:33 -0700 (PDT) Date: Thu, 1 Jun 2023 03:10:28 +0000 In-Reply-To: <20230601031028.544244-1-badhri@google.com> Mime-Version: 1.0 References: <20230601031028.544244-1-badhri@google.com> X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Message-ID: <20230601031028.544244-2-badhri@google.com> Subject: [PATCH v6 2/2] usb: gadget: udc: core: Prevent soft_connect_store() race From: Badhri Jagan Sridharan To: gregkh@linuxfoundation.org, stern@rowland.harvard.edu, colin.i.king@gmail.com, xuetao09@huawei.com, quic_eserrao@quicinc.com, water.zhangjiantao@huawei.com, peter.chen@freescale.com, balbi@ti.com, francesco@dolcini.it, alistair@alistair23.me, stephan@gerhold.net, bagasdotme@gmail.com, luca@z3ntu.xyz Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Badhri Jagan Sridharan X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1767469374944681609?= X-GMAIL-MSGID: =?utf-8?q?1767469374944681609?= usb_udc_connect_control(), soft_connect_store() and usb_gadget_deactivate() can potentialy race against each other to invoke usb_gadget_connect()/usb_gadget_disconnect(). To prevent this, guarding udc->vbus, udc->started, gadget->allow_connect, gadget->deactivate with connect_lock so that ->pullup() is only invoked when gadget driver is bound, not deactivated and started. usb_gadget_connect_locked(), usb_gadget_disconnect_locked(), usb_udc_connect_control_locked(), usb_gadget_udc_start_locked(), usb_gadget_udc_stop_locked() are called with this lock held. This commit was reverted due to the crash reported in https://lore.kernel.org/all/ZF4BvgsOyoKxdPFF@francesco-nb.int.toradex.com/. commit 16737e78d190 ("usb: gadget: udc: core: Offload usb_udc_vbus_handler processing") addresses the crash reported. Cc: stable@vger.kernel.org Fixes: 628ef0d273a6 ("usb: udc: add usb_udc_vbus_handler") Signed-off-by: Badhri Jagan Sridharan --- v5 is the first version in this series. Changes since v5: ** Fixed up commit message ** Wrapped comments at 76. --- drivers/usb/gadget/udc/core.c | 151 ++++++++++++++++++++++++---------- 1 file changed, 109 insertions(+), 42 deletions(-) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index d2e4f78c53e3..b53f74fcad60 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -40,6 +40,11 @@ static const struct bus_type gadget_bus_type; * @allow_connect: Indicates whether UDC is allowed to be pulled up. * Set/cleared by gadget_(un)bind_driver() after gadget driver is bound or * unbound. + * @connect_lock: protects udc->vbus, udc->started, gadget->connect, + * gadget->deactivate. usb_gadget_connect_locked, + * usb_gadget_disconnect_locked, usb_udc_connect_control_locked, + * usb_gadget_udc_start_locked, usb_gadget_udc_stop_locked are called with + * this lock held. * * This represents the internal data structure which is used by the UDC-class * to hold information about udc driver and gadget together. @@ -53,6 +58,7 @@ struct usb_udc { bool started; bool allow_connect; struct work_struct vbus_work; + struct mutex connect_lock; }; static struct class *udc_class; @@ -692,17 +698,12 @@ int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) } EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect); -/** - * usb_gadget_connect - software-controlled connect to USB host - * @gadget:the peripheral being connected - * - * Enables the D+ (or potentially D-) pullup. The host will start - * enumerating this gadget when the pullup is active and a VBUS session - * is active (the link is powered). - * - * Returns zero on success, else negative errno. +/* + * Internal version of usb_gadget_connect needs to be called with + * connect_lock held. */ -int usb_gadget_connect(struct usb_gadget *gadget) +static int usb_gadget_connect_locked(struct usb_gadget *gadget) + __must_hold(&gadget->udc->connect_lock) { int ret = 0; @@ -711,10 +712,12 @@ int usb_gadget_connect(struct usb_gadget *gadget) goto out; } - if (gadget->deactivated || !gadget->udc->allow_connect) { + if (gadget->deactivated || !gadget->udc->allow_connect || !gadget->udc->started) { /* * If gadget is deactivated we only save new state. * Gadget will be connected automatically after activation. + * + * udc first needs to be started before gadget can be pulled up. */ gadget->connected = true; goto out; @@ -729,22 +732,35 @@ int usb_gadget_connect(struct usb_gadget *gadget) return ret; } -EXPORT_SYMBOL_GPL(usb_gadget_connect); /** - * usb_gadget_disconnect - software-controlled disconnect from USB host - * @gadget:the peripheral being disconnected - * - * Disables the D+ (or potentially D-) pullup, which the host may see - * as a disconnect (when a VBUS session is active). Not all systems - * support software pullup controls. + * usb_gadget_connect - software-controlled connect to USB host + * @gadget:the peripheral being connected * - * Following a successful disconnect, invoke the ->disconnect() callback - * for the current gadget driver so that UDC drivers don't need to. + * Enables the D+ (or potentially D-) pullup. The host will start + * enumerating this gadget when the pullup is active and a VBUS session + * is active (the link is powered). * * Returns zero on success, else negative errno. */ -int usb_gadget_disconnect(struct usb_gadget *gadget) +int usb_gadget_connect(struct usb_gadget *gadget) +{ + int ret; + + mutex_lock(&gadget->udc->connect_lock); + ret = usb_gadget_connect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(usb_gadget_connect); + +/* + * Internal version of usb_gadget_disconnect needs to be called with + * connect_lock held. + */ +static int usb_gadget_disconnect_locked(struct usb_gadget *gadget) + __must_hold(&gadget->udc->connect_lock) { int ret = 0; @@ -756,10 +772,12 @@ int usb_gadget_disconnect(struct usb_gadget *gadget) if (!gadget->connected) goto out; - if (gadget->deactivated) { + if (gadget->deactivated || !gadget->udc->started) { /* * If gadget is deactivated we only save new state. * Gadget will stay disconnected after activation. + * + * udc should have been started before gadget being pulled down. */ gadget->connected = false; goto out; @@ -779,6 +797,30 @@ int usb_gadget_disconnect(struct usb_gadget *gadget) return ret; } + +/** + * usb_gadget_disconnect - software-controlled disconnect from USB host + * @gadget:the peripheral being disconnected + * + * Disables the D+ (or potentially D-) pullup, which the host may see + * as a disconnect (when a VBUS session is active). Not all systems + * support software pullup controls. + * + * Following a successful disconnect, invoke the ->disconnect() callback + * for the current gadget driver so that UDC drivers don't need to. + * + * Returns zero on success, else negative errno. + */ +int usb_gadget_disconnect(struct usb_gadget *gadget) +{ + int ret; + + mutex_lock(&gadget->udc->connect_lock); + ret = usb_gadget_disconnect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock); + + return ret; +} EXPORT_SYMBOL_GPL(usb_gadget_disconnect); /** @@ -799,10 +841,11 @@ int usb_gadget_deactivate(struct usb_gadget *gadget) if (gadget->deactivated) goto out; + mutex_lock(&gadget->udc->connect_lock); if (gadget->connected) { - ret = usb_gadget_disconnect(gadget); + ret = usb_gadget_disconnect_locked(gadget); if (ret) - goto out; + goto unlock; /* * If gadget was being connected before deactivation, we want @@ -812,6 +855,8 @@ int usb_gadget_deactivate(struct usb_gadget *gadget) } gadget->deactivated = true; +unlock: + mutex_unlock(&gadget->udc->connect_lock); out: trace_usb_gadget_deactivate(gadget, ret); @@ -835,6 +880,7 @@ int usb_gadget_activate(struct usb_gadget *gadget) if (!gadget->deactivated) goto out; + mutex_lock(&gadget->udc->connect_lock); gadget->deactivated = false; /* @@ -842,7 +888,8 @@ int usb_gadget_activate(struct usb_gadget *gadget) * while it was being deactivated, we call usb_gadget_connect(). */ if (gadget->connected) - ret = usb_gadget_connect(gadget); + ret = usb_gadget_connect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock); out: trace_usb_gadget_activate(gadget, ret); @@ -1083,19 +1130,22 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state); /* ------------------------------------------------------------------------- */ -static void usb_udc_connect_control(struct usb_udc *udc) +/* Acquire connect_lock before calling this function. */ +static void usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock) { if (udc->vbus) - usb_gadget_connect(udc->gadget); + usb_gadget_connect_locked(udc->gadget); else - usb_gadget_disconnect(udc->gadget); + usb_gadget_disconnect_locked(udc->gadget); } static void vbus_event_work(struct work_struct *work) { struct usb_udc *udc = container_of(work, struct usb_udc, vbus_work); - usb_udc_connect_control(udc); + mutex_lock(&udc->connect_lock); + usb_udc_connect_control_locked(udc); + mutex_unlock(&udc->connect_lock); } /** @@ -1144,7 +1194,7 @@ void usb_gadget_udc_reset(struct usb_gadget *gadget, EXPORT_SYMBOL_GPL(usb_gadget_udc_reset); /** - * usb_gadget_udc_start - tells usb device controller to start up + * usb_gadget_udc_start_locked - tells usb device controller to start up * @udc: The UDC to be started * * This call is issued by the UDC Class driver when it's about @@ -1155,8 +1205,11 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset); * necessary to have it powered on. * * Returns zero on success, else negative errno. + * + * Caller should acquire connect_lock before invoking this function. */ -static inline int usb_gadget_udc_start(struct usb_udc *udc) +static inline int usb_gadget_udc_start_locked(struct usb_udc *udc) + __must_hold(&udc->connect_lock) { int ret; @@ -1173,7 +1226,7 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc) } /** - * usb_gadget_udc_stop - tells usb device controller we don't need it anymore + * usb_gadget_udc_stop_locked - tells usb device controller we don't need it anymore * @udc: The UDC to be stopped * * This call is issued by the UDC Class driver after calling @@ -1182,8 +1235,11 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc) * The details are implementation specific, but it can go as * far as powering off UDC completely and disable its data * line pullups. + * + * Caller should acquire connect lock before invoking this function. */ -static inline void usb_gadget_udc_stop(struct usb_udc *udc) +static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc) + __must_hold(&udc->connect_lock) { if (!udc->started) { dev_err(&udc->dev, "UDC had already stopped\n"); @@ -1342,6 +1398,7 @@ int usb_add_gadget(struct usb_gadget *gadget) udc->gadget = gadget; gadget->udc = udc; + mutex_init(&udc->connect_lock); udc->started = false; @@ -1545,12 +1602,16 @@ static int gadget_bind_driver(struct device *dev) if (ret) goto err_bind; - ret = usb_gadget_udc_start(udc); - if (ret) + mutex_lock(&udc->connect_lock); + ret = usb_gadget_udc_start_locked(udc); + if (ret) { + mutex_unlock(&udc->connect_lock); goto err_start; + } usb_gadget_enable_async_callbacks(udc); udc->allow_connect = true; - usb_udc_connect_control(udc); + usb_udc_connect_control_locked(udc); + mutex_unlock(&udc->connect_lock); kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE); return 0; @@ -1583,12 +1644,14 @@ static void gadget_unbind_driver(struct device *dev) udc->allow_connect = false; cancel_work_sync(&udc->vbus_work); - usb_gadget_disconnect(gadget); + mutex_lock(&udc->connect_lock); + usb_gadget_disconnect_locked(gadget); usb_gadget_disable_async_callbacks(udc); if (gadget->irq) synchronize_irq(gadget->irq); udc->driver->unbind(gadget); - usb_gadget_udc_stop(udc); + usb_gadget_udc_stop_locked(udc); + mutex_unlock(&udc->connect_lock); mutex_lock(&udc_lock); driver->is_bound = false; @@ -1674,11 +1737,15 @@ static ssize_t soft_connect_store(struct device *dev, } if (sysfs_streq(buf, "connect")) { - usb_gadget_udc_start(udc); - usb_gadget_connect(udc->gadget); + mutex_lock(&udc->connect_lock); + usb_gadget_udc_start_locked(udc); + usb_gadget_connect_locked(udc->gadget); + mutex_unlock(&udc->connect_lock); } else if (sysfs_streq(buf, "disconnect")) { - usb_gadget_disconnect(udc->gadget); - usb_gadget_udc_stop(udc); + mutex_lock(&udc->connect_lock); + usb_gadget_disconnect_locked(udc->gadget); + usb_gadget_udc_stop_locked(udc); + mutex_unlock(&udc->connect_lock); } else { dev_err(dev, "unsupported command '%s'\n", buf); ret = -EINVAL;