On Tue, Oct 27, 2026 at 02:56:07PM +0200, Magnus Karlsson wrote: > On Tue, 27 Oct 2026 at 14:43, Eric Dumazet <[email protected]> wrote: > > > > Le mar. 27 oct. 2026 à 13:15, Magnus Karlsson > > <[email protected]> a écrit : > > > > > > That USO works for 64-bit systems is just pure luck. Currently, the > > > computation of the UDP segmentation header is performed using sizeof() > > > a pointer instead of the sizeof() the UDP header that the pointer > > > points to. Since the UDP header happens to be 8 bytes long and a > > > pointer is 8 bytes long on a 64-bit system, this works on all those > > > systems. But no such luck for anyone using a 32-bit system as 8 bytes > > > != 4 bytes. So fix this by using sizeof() the UDP header that the > > > pointer points to instead. > > > > > > This was found by an LLM while implementing something else that used USO. > > > > > > Fixes: c91a4f9feb67a199c2 ("add support for UDP Segmentation Offload") > > > > Missing prefix? This was really: > > > > Fixes: c91a4f9feb67 ("iavf: add support for UDP Segmentation Offload") > > You are correct on both accounts/patches. Do not know why I missed this, > sorry. > > Do you want a v2 with this added?
Current policy is that you need to wait 24h with posting next revisions. Eric marked it as 'changes requested' so yes, you need a v2. You can add my review tag as well, thanks for auditing intel drivers against this bug. MF > > > Other than this, > > Reviewed-by: Eric Dumazet <[email protected]> > > > > > Signed-off-by: Magnus Karlsson <[email protected]> > > > --- > > > drivers/net/ethernet/intel/iavf/iavf_txrx.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c > > > b/drivers/net/ethernet/intel/iavf/iavf_txrx.c > > > index 8982cf75466f..2c290d7788d2 100644 > > > --- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c > > > +++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c > > > @@ -1807,7 +1807,7 @@ static int iavf_tso(struct iavf_tx_buffer *first, > > > u8 *hdr_len, > > > csum_replace_by_diff(&l4.udp->check, > > > (__force __wsum)htonl(paylen)); > > > /* compute length of UDP segmentation header */ > > > - *hdr_len = (u8)sizeof(l4.udp) + l4_offset; > > > + *hdr_len = sizeof(*l4.udp) + l4_offset; > > > } else { > > > csum_replace_by_diff(&l4.tcp->check, > > > (__force __wsum)htonl(paylen)); > > > -- > > > 2.38.1 > > >
