Hey Nathan, On Tue, Sep 13, 2022 at 4:09 PM Nathan Chancellor <nathan@xxxxxxxxxx> wrote: > > On Mon, Sep 12, 2022 at 02:45:56PM -0700, Nathan Huckleberry wrote: > > The ndo_start_xmit field in net_device_ops is expected to be of type > > netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev). > > > > The mismatched return type breaks forward edge kCFI since the underlying > > function definition does not match the function hook definition. > > > > The return type of ieee80211_xmit should be changed from int to > > netdev_tx_t. > > > > Reported-by: Dan Carpenter <error27@xxxxxxxxx> > > Link: https://github.com/ClangBuiltLinux/linux/issues/1703 > > Cc: llvm@xxxxxxxxxxxxxxx > > Signed-off-by: Nathan Huckleberry <nhuck@xxxxxxxxxx> > > The protoype in drivers/staging/rtl8192u/ieee80211/ieee80211.h should be > updated as well. With that: Nice catch, thanks. > > Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> > > > --- > > drivers/staging/rtl8192u/ieee80211/ieee80211_tx.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_tx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_tx.c > > index 8602e3a6c837..e4b6454809a0 100644 > > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_tx.c > > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_tx.c > > @@ -526,7 +526,7 @@ static void ieee80211_query_seqnum(struct ieee80211_device *ieee, > > } > > } > > > > -int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev) > > +netdev_tx_t ieee80211_xmit(struct sk_buff *skb, struct net_device *dev) > > { > > struct ieee80211_device *ieee = netdev_priv(dev); > > struct ieee80211_txb *txb = NULL; > > @@ -822,13 +822,13 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev) > > if ((*ieee->hard_start_xmit)(txb, dev) == 0) { > > stats->tx_packets++; > > stats->tx_bytes += __le16_to_cpu(txb->payload_size); > > - return 0; > > + return NETDEV_TX_OK; > > } > > ieee80211_txb_free(txb); > > } > > } > > > > - return 0; > > + return NETDEV_TX_OK; > > > > failed: > > spin_unlock_irqrestore(&ieee->lock, flags); > > I see 'return 1' down here, that doesn't appear to be a valid > 'netdev_tx_t'. Should that be 'return NETDEV_TX_BUSY'? I guess that is > an outstanding issue though, just figured I would mention it. I'm not sure. As far as I can tell, the dev_xmit_complete function in include/linux/netdevice.h is used to determine whether an skb was consumed or not. It looks like a value of 1 (NET_XMIT_DROP) would signify that it was consumed, whereas NETDEV_TX_BUSY would not. It's somewhat confusing that a function which returns an enum may also return values outside of that enum. For more info see the foillowing commits: dc1f8bf68b311b1537cb65893430b6796118498a 572a9d7b6fc7f20f573664063324c086be310c42 7f2e870f2a48a0524a3b03b04fa019311d16a7f7 > > > -- > > 2.37.2.789.g6183377224-goog > > > > Cheers, > Nathan Thanks, Huck
