On Wed, 14 Apr 2021 19:06:52 -0700
Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx> wrote:
> kerneljasonxing@xxxxxxxxx wrote:
>
> > From: Jason Xing <xingwanli@xxxxxxxxxxxx>
> >
> > Fix this panic by adding more rules to calculate the value of @rss_size_max
> > which could be used in allocating the queues when bpf is loaded, which,
> > however, could cause the failure and then trigger the NULL pointer of
> > vsi->rx_rings. Prio to this fix, the machine doesn't care about how many
> > cpus are online and then allocates 256 queues on the machine with 32 cpus
> > online actually.
> >
> > Once the load of bpf begins, the log will go like this "failed to get
> > tracking for 256 queues for VSI 0 err -12" and this "setup of MAIN VSI
> > failed".
> >
> > Thus, I attach the key information of the crash-log here.
> >
> > BUG: unable to handle kernel NULL pointer dereference at
> > 0000000000000000
> > RIP: 0010:i40e_xdp+0xdd/0x1b0 [i40e]
> > Call Trace:
> > [2160294.717292] ? i40e_reconfig_rss_queues+0x170/0x170 [i40e]
> > [2160294.717666] dev_xdp_install+0x4f/0x70
> > [2160294.718036] dev_change_xdp_fd+0x11f/0x230
> > [2160294.718380] ? dev_disable_lro+0xe0/0xe0
> > [2160294.718705] do_setlink+0xac7/0xe70
> > [2160294.719035] ? __nla_parse+0xed/0x120
> > [2160294.719365] rtnl_newlink+0x73b/0x860
> >
> > Fixes: 41c445ff0f48 ("i40e: main driver core")
> > Co-developed-by: Shujin Li <lishujin@xxxxxxxxxxxx>
> > Signed-off-by: Shujin Li <lishujin@xxxxxxxxxxxx>
> > Signed-off-by: Jason Xing <xingwanli@xxxxxxxxxxxx>
>
> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
>
> @Jakub/@DaveM - feel free to apply this directly.
Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
The crash/bug happens in this code:
static int i40e_xdp_setup(struct i40e_vsi *vsi, struct bpf_prog *prog,
struct netlink_ext_ack *extack)
{
[...]
for (i = 0; i < vsi->num_queue_pairs; i++)
WRITE_ONCE(vsi->rx_rings[i]->xdp_prog, vsi->xdp_prog);
And this is a side effect of i40e_setup_pf_switch() failing with "setup
of MAIN VSI failed".
LGTM
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
