+ linux-wireless
On 4/20/2017 1:16 PM, James Hughes wrote:
The driver was adding header information to incoming skb
without ensuring the head was uncloned and hence writable.
skb_cow_head has been used to ensure they are writable, however,
this required some changes to error handling to ensure that
if skb_cow_head failed it was not ignored.
This really needs to be reviewed by someone who is more familiar
with this code base to ensure any deallocation of skb's is
still correct.
Signed-off-by: James Hughes <james.hug...@raspberrypi.org>
---
.../wireless/broadcom/brcm80211/brcmfmac/bcdc.c | 15 ++++++++--
.../wireless/broadcom/brcm80211/brcmfmac/core.c | 23 +++++-----------
.../broadcom/brcm80211/brcmfmac/fwsignal.c | 32 +++++++++++++++++-----
.../wireless/broadcom/brcm80211/brcmfmac/sdio.c | 7 ++++-
4 files changed, 51 insertions(+), 26 deletions(-)
[...]
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index 5eaac13..08272e8 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -198,7 +198,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff
*skb,
int ret;
struct brcmf_if *ifp = netdev_priv(ndev);
struct brcmf_pub *drvr = ifp->drvr;
- struct ethhdr *eh = (struct ethhdr *)(skb->data);
+ struct ethhdr *eh;
brcmf_dbg(DATA, "Enter, bsscfgidx=%d\n", ifp->bsscfgidx);
@@ -212,23 +212,14 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
}
/* Make sure there's enough room for any header */
- if (skb_headroom(skb) < drvr->hdrlen) {
- struct sk_buff *skb2;
-
- brcmf_dbg(INFO, "%s: insufficient headroom\n",
- brcmf_ifname(ifp));
- drvr->bus_if->tx_realloc++;
- skb2 = skb_realloc_headroom(skb, drvr->hdrlen);
- dev_kfree_skb(skb);
- skb = skb2;
- if (skb == NULL) {
- brcmf_err("%s: skb_realloc_headroom failed\n",
- brcmf_ifname(ifp));
- ret = -ENOMEM;
- goto done;
- }
What you are throwing away here is code that assures there is sufficient
headroom for protocol and bus layer in the tx path, because that is
determined by drvr->hdrlen. This is where the skb is handed to the
driver so if you could leave the functionality above *and* assure it is
writeable that would be the best solution as there is no need for all
the other changes down the tx path.
+ ret = skb_cow_head(skb, drvr->hdrlen);
+ if (ret) {
So move the realloc code above here instead of simply freeing the skb.
+ dev_kfree_skb_any(skb);
+ goto done;
}
+ eh = (struct ethhdr *)(skb->data);
Now this is actually a separate fix so I would like a separate patch for it.
I have a RPi3 sitting on my desk so how can I replicate the issue. It
was something about broadcast/multicast traffic when using AP mode and a
bridge, right?
Regards,
Arend
