> -----Original Message----- > From: Intel-wired-lan <[email protected]> On Behalf Of > Corinna Vinschen > Sent: Thursday, July 18, 2024 2:27 PM > To: [email protected]; [email protected]; Eric Dumazet > <[email protected]> > Cc: Jason Xing <[email protected]>; Nikolay Aleksandrov > <[email protected]>; [email protected]; Nguyen, Anthony L > <[email protected]>; Jakub Kicinski <[email protected]>; Paolo Abeni > <[email protected]>; David S . Miller <[email protected]> > Subject: [Intel-wired-lan] [PATCH net v3] igb: cope with large MAX_SKB_FRAGS. > > From: Paolo Abeni <[email protected]> > > Sabrina reports that the igb driver does not cope well with large > MAX_SKB_FRAG values: setting MAX_SKB_FRAG to 45 causes payload corruption on > TX. > > An easy reproducer is to run ssh to connect to the machine. With > MAX_SKB_FRAGS=17 it works, with MAX_SKB_FRAGS=45 it fails. > > The root cause of the issue is that the driver does not take into account > properly the (possibly large) shared info size when selecting the ring > layout, and will try to fit two packets inside the same 4K page even when the > 1st fraglist will trump over the 2nd head. > > Address the issue forcing the driver to fit a single packet per page, leaving > there enough room to store the (currently) largest possible skb_shared_info. > > Fixes: 3948b05950fd ("net: introduce a config option to tweak MAX_SKB_FRAGS") > Reported-by: Jan Tluka <[email protected]> > Reported-by: Jirka Hladky <[email protected]> > Reported-by: Sabrina Dubroca <[email protected]> > Tested-by: Sabrina Dubroca <[email protected]> > Tested-by: Corinna Vinschen <[email protected]> > Signed-off-by: Paolo Abeni <[email protected]> > --- > v2: fix subject, add a simple reproducer > v3: fix Fixes, tested with all MTUs from 1200 to 1280 per Eric's suggestion > > drivers/net/ethernet/intel/igb/igb_main.c | 1 + > 1 file changed, 1 insertion(+) >
Tested-by: Pucha Himasekhar Reddy <[email protected]> (A Contingent worker at Intel)
