On 18/09/2024 17:06, Jiwon Kim wrote: > syzbot reported a WARNING in bond_xdp_get_xmit_slave. To reproduce > this[1], one bond device (bond1) has xdpdrv, which increases > bpf_master_redirect_enabled_key. Another bond device (bond0) which is > unsupported by XDP but its slave (veth3) has xdpgeneric that returns > XDP_TX. This triggers WARN_ON_ONCE() from the xdp_master_redirect(). > To reduce unnecessary warnings and improve log management, we need to > delete the WARN_ON_ONCE() and add ratelimit to the netdev_err(). > > [1] Steps to reproduce: > # Needs tx_xdp with return XDP_TX; > ip l add veth0 type veth peer veth1 > ip l add veth3 type veth peer veth4 > ip l add bond0 type bond mode 6 # BOND_MODE_ALB, unsupported by XDP > ip l add bond1 type bond # BOND_MODE_ROUNDROBIN by default > ip l set veth0 master bond1 > ip l set bond1 up > # Increases bpf_master_redirect_enabled_key > ip l set dev bond1 xdpdrv object tx_xdp.o section xdp_tx > ip l set veth3 master bond0 > ip l set bond0 up > ip l set veth4 up > # Triggers WARN_ON_ONCE() from the xdp_master_redirect() > ip l set veth3 xdpgeneric object tx_xdp.o section xdp_tx > > Reported-by: syzbot+c187823a52ed505b2257@xxxxxxxxxxxxxxxxxxxxxxxxx > Closes: https://syzkaller.appspot.com/bug?extid=c187823a52ed505b2257 > Fixes: 9e2ee5c7e7c3 ("net, bonding: Add XDP support to the bonding driver") > Signed-off-by: Jiwon Kim <jiwonaid0@xxxxxxxxx> > --- > v3: Fix subject and description > v2: Change the patch to fix bond_xdp_get_xmit_slave > --- > drivers/net/bonding/bond_main.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c > index b560644ee1b1..b1bffd8e9a95 100644 > --- a/drivers/net/bonding/bond_main.c > +++ b/drivers/net/bonding/bond_main.c > @@ -5610,9 +5610,9 @@ bond_xdp_get_xmit_slave(struct net_device *bond_dev, struct xdp_buff *xdp) > break; > > default: > - /* Should never happen. Mode guarded by bond_xdp_check() */ > - netdev_err(bond_dev, "Unknown bonding mode %d for xdp xmit\n", BOND_MODE(bond)); > - WARN_ON_ONCE(1); > + if (net_ratelimit()) > + netdev_err(bond_dev, "Unknown bonding mode %d for xdp xmit\n", > + BOND_MODE(bond)); > return NULL; > } > Looks good to me, but next time wait 1 day before reposting another version. Signed-off-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>