| Message ID | 20170726084924.27546-1-daniels@collabora.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Kalle Valo |
| Headers | show |
On 7/26/2017 10:49 AM, Daniel Stone wrote: > The commit to rework the headroom check in start_xmit() now calls > pxskb_expand_head() unconditionally if the header is CoW. Unfortunately, > it does so with the delta between the extant headroom and the header > length, which may be negative if there is already sufficient headroom. > > pskb_expand_head() does allow for size being 0, in which case it just > copies, so clamp the header delta to zero. > > Opening Chrome (and all my tabs) on a PCIE device was enough to reliably > hit this. > > Fixes: 270a6c1f65fe ("brcmfmac: rework headroom check in .start_xmit()") > Signed-off-by: Daniel Stone <daniels@collabora.com> > Cc: Arend Van Spriel <arend.vanspriel@broadcom.com> > Cc: James Hughes <james.hughes@raspberrypi.org> > Cc: Hante Meuleman <hante.meuleman@broadcom.com> > Cc: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> > Cc: Franky Lin <franky.lin@broadcom.com> > --- > drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 1 + > 1 file changed, 1 insertion(+) > > Really sorry, I forgot to re-run format-patch after fixing the initial > patch. I've run out of coffee. :( Sufficient coffee over here so I have no excuse. You are obviously right. Please tag this patch for 4.13, ie.: [PATCH for-4.13 V3] brcmfmac: .... > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > index 2153e8062b4c..42dbd5a8c220 100644 > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > @@ -215,6 +215,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb, > /* Make sure there's enough writeable headroom */ > if (skb_headroom(skb) < drvr->hdrlen || skb_header_cloned(skb)) { > head_delta = drvr->hdrlen - skb_headroom(skb); > + head_delta = max(head_delta, 0); minor nit, but can you make it: - head_delta = drvr->hdrlen - skb_headroom(skb); + head_delta = max(drvr->hdrlen - skb_headroom(skb), 0); Regards, Arend
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c index 2153e8062b4c..42dbd5a8c220 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c @@ -215,6 +215,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb, /* Make sure there's enough writeable headroom */ if (skb_headroom(skb) < drvr->hdrlen || skb_header_cloned(skb)) { head_delta = drvr->hdrlen - skb_headroom(skb); + head_delta = max(head_delta, 0); brcmf_dbg(INFO, "%s: insufficient headroom (%d)\n", brcmf_ifname(ifp), head_delta);
The commit to rework the headroom check in start_xmit() now calls pxskb_expand_head() unconditionally if the header is CoW. Unfortunately, it does so with the delta between the extant headroom and the header length, which may be negative if there is already sufficient headroom. pskb_expand_head() does allow for size being 0, in which case it just copies, so clamp the header delta to zero. Opening Chrome (and all my tabs) on a PCIE device was enough to reliably hit this. Fixes: 270a6c1f65fe ("brcmfmac: rework headroom check in .start_xmit()") Signed-off-by: Daniel Stone <daniels@collabora.com> Cc: Arend Van Spriel <arend.vanspriel@broadcom.com> Cc: James Hughes <james.hughes@raspberrypi.org> Cc: Hante Meuleman <hante.meuleman@broadcom.com> Cc: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com> Cc: Franky Lin <franky.lin@broadcom.com> --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 1 + 1 file changed, 1 insertion(+) Really sorry, I forgot to re-run format-patch after fixing the initial patch. I've run out of coffee. :(