From: Al Viro <v...@zeniv.linux.org.uk>

3.4.108-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit f01d35a15fa04162a58b95970fc01fa70ec9dacd upstream.

AIO_PREAD requests call ->aio_read() with iovec on caller's stack, so if
we are going to access it asynchronously, we'd better get ourselves
a copy - the one on kernel stack of aio_run_iocb() won't be there
anymore.  function/f_fs.c take care of doing that, legacy/inode.c
doesn't...

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
[lizf: Backproted to 3.4:
 - adjust context
 - need kfree() after calling get_ready_ep()]
Signed-off-by: Zefan Li <lize...@huawei.com>
---
 drivers/usb/gadget/inode.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c
index d9eaaa3..093e907 100644
--- a/drivers/usb/gadget/inode.c
+++ b/drivers/usb/gadget/inode.c
@@ -570,6 +570,7 @@ static ssize_t ep_aio_read_retry(struct kiocb *iocb)
                        break;
        }
        kfree(priv->buf);
+       kfree(priv->iv);
        kfree(priv);
        return len;
 }
@@ -591,6 +592,7 @@ static void ep_aio_complete(struct usb_ep *ep, struct 
usb_request *req)
         */
        if (priv->iv == NULL || unlikely(req->actual == 0)) {
                kfree(req->buf);
+               kfree(priv->iv);
                kfree(priv);
                iocb->private = NULL;
                /* aio_complete() reports bytes-transferred _and_ faults */
@@ -626,7 +628,7 @@ ep_aio_rwtail(
        struct usb_request      *req;
        ssize_t                 value;
 
-       priv = kmalloc(sizeof *priv, GFP_KERNEL);
+       priv = kzalloc(sizeof *priv, GFP_KERNEL);
        if (!priv) {
                value = -ENOMEM;
 fail:
@@ -634,11 +636,19 @@ fail:
                return value;
        }
        iocb->private = priv;
-       priv->iv = iv;
+       if (iv) {
+               priv->iv = kmemdup(iv, nr_segs * sizeof(struct iovec),
+                                  GFP_KERNEL);
+               if (!priv->iv) {
+                       kfree(priv);
+                       goto fail;
+               }
+       }
        priv->nr_segs = nr_segs;
 
        value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
        if (unlikely(value < 0)) {
+               kfree(priv->iv);
                kfree(priv);
                goto fail;
        }
@@ -672,6 +682,7 @@ fail:
        mutex_unlock(&epdata->lock);
 
        if (unlikely(value)) {
+               kfree(priv->iv);
                kfree(priv);
                put_ep(epdata);
        } else
-- 
1.9.1

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