From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54090 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751877AbdIVQ3V (ORCPT ); Fri, 22 Sep 2017 12:29:21 -0400 Subject: patch "USB: gadgetfs: fix copy_to_user while holding spinlock" added to usb-linus To: stern@rowland.harvard.edu, andreyknvl@google.com, felipe.balbi@linux.intel.com, gregkh@linuxfoundation.org, stable@vger.kernel.org From: Date: Fri, 22 Sep 2017 18:29:22 +0200 Message-ID: <150609776215540@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled USB: gadgetfs: fix copy_to_user while holding spinlock to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >>From 6e76c01e71551cb221c1f3deacb9dcd9a7346784 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 21 Sep 2017 16:12:01 -0400 Subject: USB: gadgetfs: fix copy_to_user while holding spinlock The gadgetfs driver as a long-outstanding FIXME, regarding a call of copy_to_user() made while holding a spinlock. This patch fixes the issue by dropping the spinlock and using the dev->udc_usage mechanism introduced by another recent patch to guard against status changes while the lock isn't held. Signed-off-by: Alan Stern Reported-by: Andrey Konovalov CC: Acked-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/legacy/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 684900fcfe24..956b3dc7c3a4 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -983,11 +983,14 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr) retval = -EIO; else { len = min (len, (size_t)dev->req->actual); -// FIXME don't call this with the spinlock held ... + ++dev->udc_usage; + spin_unlock_irq(&dev->lock); if (copy_to_user (buf, dev->req->buf, len)) retval = -EFAULT; else retval = len; + spin_lock_irq(&dev->lock); + --dev->udc_usage; clean_req (dev->gadget->ep0, dev->req); /* NOTE userspace can't yet choose to stall */ } -- 2.14.1