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https://github.com/Divested-Mobile/DivestOS-Build.git
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41 lines
1.6 KiB
Diff
41 lines
1.6 KiB
Diff
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From 6e76c01e71551cb221c1f3deacb9dcd9a7346784 Mon Sep 17 00:00:00 2001
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From: Alan Stern <stern@rowland.harvard.edu>
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Date: Thu, 21 Sep 2017 16:12:01 -0400
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Subject: [PATCH] USB: gadgetfs: fix copy_to_user while holding spinlock
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The gadgetfs driver as a long-outstanding FIXME, regarding a call of
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copy_to_user() made while holding a spinlock. This patch fixes the
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issue by dropping the spinlock and using the dev->udc_usage mechanism
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introduced by another recent patch to guard against status changes
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while the lock isn't held.
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Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
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Reported-by: Andrey Konovalov <andreyknvl@google.com>
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CC: <stable@vger.kernel.org>
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Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/usb/gadget/legacy/inode.c | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
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index 684900fcfe24c..956b3dc7c3a4d 100644
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--- a/drivers/usb/gadget/legacy/inode.c
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+++ b/drivers/usb/gadget/legacy/inode.c
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@@ -983,11 +983,14 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
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retval = -EIO;
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else {
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len = min (len, (size_t)dev->req->actual);
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-// FIXME don't call this with the spinlock held ...
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+ ++dev->udc_usage;
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+ spin_unlock_irq(&dev->lock);
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if (copy_to_user (buf, dev->req->buf, len))
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retval = -EFAULT;
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else
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retval = len;
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+ spin_lock_irq(&dev->lock);
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+ --dev->udc_usage;
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clean_req (dev->gadget->ep0, dev->req);
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/* NOTE userspace can't yet choose to stall */
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}
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