Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964981AbaFXP4E (ORCPT ); Tue, 24 Jun 2014 11:56:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33283 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964962AbaFXP4A (ORCPT ); Tue, 24 Jun 2014 11:56:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiao Jin , Johan Hovold Subject: [PATCH 3.15 28/61] USB: cdc-acm: fix broken runtime suspend Date: Tue, 24 Jun 2014 11:51:11 -0400 Message-Id: <20140624154954.053014519@linuxfoundation.org> X-Mailer: git-send-email 2.0.0 In-Reply-To: <20140624154952.751713761@linuxfoundation.org> References: <20140624154952.751713761@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 140cb81ac8c625942a1d695875932c615767a526 upstream. The current ACM runtime-suspend implementation is broken in several ways: Firstly, it buffers only the first write request being made while suspended -- any further writes are silently dropped. Secondly, writes being dropped also leak write urbs, which are never reclaimed (until the device is unbound). Thirdly, even the single buffered write is not cleared at shutdown (which may happen before the device is resumed), something which can lead to another urb leak as well as a PM usage-counter leak. Fix this by implementing a delayed-write queue using urb anchors and making sure to discard the queue properly at shutdown. Fixes: 11ea859d64b6 ("USB: additional power savings for cdc-acm devices that support remote wakeup") Reported-by: Xiao Jin Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 32 ++++++++++++++++++++++---------- drivers/usb/class/cdc-acm.h | 2 +- 2 files changed, 23 insertions(+), 11 deletions(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -573,6 +573,8 @@ static void acm_port_destruct(struct tty static void acm_port_shutdown(struct tty_port *port) { struct acm *acm = container_of(port, struct acm, port); + struct urb *urb; + struct acm_wb *wb; int i; dev_dbg(&acm->control->dev, "%s\n", __func__); @@ -581,6 +583,16 @@ static void acm_port_shutdown(struct tty if (!acm->disconnected) { usb_autopm_get_interface(acm->control); acm_set_control(acm, acm->ctrlout = 0); + + for (;;) { + urb = usb_get_from_anchor(&acm->delayed); + if (!urb) + break; + wb = urb->context; + wb->use = 0; + usb_autopm_put_interface_async(acm->control); + } + usb_kill_urb(acm->ctrlurb); for (i = 0; i < ACM_NW; i++) usb_kill_urb(acm->wb[i].urb); @@ -648,12 +660,9 @@ static int acm_tty_write(struct tty_stru usb_autopm_get_interface_async(acm->control); if (acm->susp_count) { - if (!acm->delayed_wb) - acm->delayed_wb = wb; - else - usb_autopm_put_interface_async(acm->control); + usb_anchor_urb(wb->urb, &acm->delayed); spin_unlock_irqrestore(&acm->write_lock, flags); - return count; /* A white lie */ + return count; } usb_mark_last_busy(acm->dev); @@ -1269,6 +1278,7 @@ made_compressed_probe: acm->bInterval = epread->bInterval; tty_port_init(&acm->port); acm->port.ops = &acm_port_ops; + init_usb_anchor(&acm->delayed); buf = usb_alloc_coherent(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma); if (!buf) { @@ -1539,7 +1549,7 @@ static int acm_suspend(struct usb_interf static int acm_resume(struct usb_interface *intf) { struct acm *acm = usb_get_intfdata(intf); - struct acm_wb *wb; + struct urb *urb; int rv = 0; spin_lock_irq(&acm->read_lock); @@ -1551,10 +1561,12 @@ static int acm_resume(struct usb_interfa if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) { rv = usb_submit_urb(acm->ctrlurb, GFP_ATOMIC); - if (acm->delayed_wb) { - wb = acm->delayed_wb; - acm->delayed_wb = NULL; - acm_start_wb(acm, wb); + for (;;) { + urb = usb_get_from_anchor(&acm->delayed); + if (!urb) + break; + + acm_start_wb(acm, urb->context); } /* --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -120,7 +120,7 @@ struct acm { unsigned int throttled:1; /* actually throttled */ unsigned int throttle_req:1; /* throttle requested */ u8 bInterval; - struct acm_wb *delayed_wb; /* write queued for a device about to be woken */ + struct usb_anchor delayed; /* writes queued for a device about to be woken */ }; #define CDC_DATA_INTERFACE_TYPE 0x0a -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/