On 9/18/24 16:06, 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>
Isn't the above issue completely addressed by explicitly checking for
bond->prog in bond_xdp_get_xmit_slave()? Or would that broke some use-case?
Thanks,
Paolo
