4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Hughes <james.hughes@xxxxxxxxxxxxxxx> commit 9cc4b7cb86cbcc6330a3faa8cd65268cd2d3c227 upstream. The driver was making changes to the skb_header without ensuring it was writable (i.e. uncloned). This patch also removes some boiler plate header size checking/adjustment code as that is also handled by the skb_cow_header function used to make header writable. Signed-off-by: James Hughes <james.hughes@xxxxxxxxxxxxxxx> Acked-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Signed-off-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/brcm80211/brcmfmac/core.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) --- a/drivers/net/wireless/brcm80211/brcmfmac/core.c +++ b/drivers/net/wireless/brcm80211/brcmfmac/core.c @@ -232,22 +232,13 @@ static netdev_tx_t brcmf_netdev_start_xm goto done; } - /* 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", + /* Make sure there's enough writable headroom*/ + ret = skb_cow_head(skb, drvr->hdrlen); + if (ret < 0) { + brcmf_err("%s: skb_cow_head failed\n", brcmf_ifname(drvr, ifp->bssidx)); - 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(drvr, ifp->bssidx)); - ret = -ENOMEM; - goto done; - } + goto done; } /* validate length for ether packet */