i40e: fix the panic when running bpf in xdpdrv mode

commit 4e39a072a6a0fc422ba7da5e4336bdc295d70211 upstream.

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@kuaishou.com>
Signed-off-by: Shujin Li <lishujin@kuaishou.com>
Signed-off-by: Jason Xing <xingwanli@kuaishou.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 043b69b5843b0c481a2fe51f991c4dfcaf18558d..40644657b1b74e0e1d6a99f4b0dfdf701a5ed0a3 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -8504,6 +8504,7 @@ static int i40e_sw_init(struct i40e_pf *pf)
 {
        int err = 0;
        int size;
+       u16 pow;
 
        pf->msg_enable = netif_msg_init(I40E_DEFAULT_MSG_ENABLE,
                                (NETIF_MSG_DRV|NETIF_MSG_PROBE|NETIF_MSG_LINK));
@@ -8531,6 +8532,11 @@ static int i40e_sw_init(struct i40e_pf *pf)
        pf->rss_table_size = pf->hw.func_caps.rss_table_size;
        pf->rss_size_max = min_t(int, pf->rss_size_max,
                                 pf->hw.func_caps.num_tx_qp);
+
+       /* find the next higher power-of-2 of num cpus */
+       pow = roundup_pow_of_two(num_online_cpus());
+       pf->rss_size_max = min_t(int, pf->rss_size_max, pow);
+
        if (pf->hw.func_caps.rss) {
                pf->flags |= I40E_FLAG_RSS_ENABLED;
                pf->alloc_rss_size = min_t(int, pf->rss_size_max,