lkml.org 
[lkml]   [2017]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4.4 35/46] ravb: unmap descriptors when freeing rings
On Thu, Jun 29, 2017 at 02:58:09PM +0100, Ben Hutchings wrote:
> On Thu, 2017-06-15 at 19:52 +0200, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
> >
> >
> > [ Upstream commit a47b70ea86bdeb3091341f5ae3ef580f1a1ad822 ]
> >
> > "swiotlb buffer is full" errors occur after repeated initialisation of a
> > device - f.e. suspend/resume or ip link set up/down. This is because memory
> > mapped using dma_map_single() in ravb_ring_format() and ravb_start_xmit()
> > is not released. Resolve this problem by unmapping descriptors when
> > freeing rings.
>
> This should be followed by:
>
> commit 79514ef670e9e575a1fe36922268c439d0f0ca8a
> Author: Eugeniu Rosca <erosca@de.adit-jv.com>
> Date: Tue Jun 6 00:08:10 2017 +0200
>
> ravb: Fix use-after-free on `ifconfig eth0 down`

Thanks, now queued up.

> But also, this loop looks wrong:
>
> [...]
> > if (priv->rx_ring[q]) {
> > + for (i = 0; i < priv->num_rx_ring[q]; i++) {
> > + struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
> > +
> > + if (!dma_mapping_error(ndev->dev.parent,
> > + le32_to_cpu(desc->dptr)))
> > + dma_unmap_single(ndev->dev.parent,
> > + le32_to_cpu(desc->dptr),
> > + PKT_BUF_SZ,
> > + DMA_FROM_DEVICE);
> > + }
> [...]
>
> It's possible that the driver hasn't filled (or attempted to fill or
> refill) every RX descriptor, so this could result in a double-unmap. I
> think this needs to use cur_rx and dirty_rx to determine which
> descriptors to process.

I'll let Kazuya fix that :)

thanks,

greg k-h

\
 
 \ /
  Last update: 2017-07-03 14:53    [W:0.118 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site