Re: [PATCH] ixgbe: Fix NULL pointer dereference in ixgbe_xdp_setup
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: 2021-08-17 11:25:43
Also in:
intel-wired-lan, lkml, netdev
On Tue, Aug 17, 2021 at 03:54:07PM +0800, Feng zhou wrote:
From: Feng Zhou <redacted> The ixgbe driver currently generates a NULL pointer dereference with some machine (online cpus < 63). This is due to the fact that the maximum value of num_xdp_queues is nr_cpu_ids. Code is in "ixgbe_set_rss_queues"".
That's a good catch, but we should fix set channels callback so that it will not allow a setting of queues to be higher than the num_online_cpus(). Please also include the tree in the patch subject that you're directing the patch to. I'd be also thankful if you Cc me on Intel XDP related patches. Thanks!
quoted hunk ↗ jump to hunk
Here's how the problem repeats itself: Some machine (online cpus < 63), And user set num_queues to 63 through ethtool. Code is in the "ixgbe_set_channels", adapter->ring_feature[RING_F_FDIR].limit = count; It becames 63. When user use xdp, "ixgbe_set_rss_queues" will set queues num. adapter->num_rx_queues = rss_i; adapter->num_tx_queues = rss_i; adapter->num_xdp_queues = ixgbe_xdp_queues(adapter); And rss_i's value is from f = &adapter->ring_feature[RING_F_FDIR]; rss_i = f->indices = f->limit; So "num_rx_queues" > "num_xdp_queues", when run to "ixgbe_xdp_setup", for (i = 0; i < adapter->num_rx_queues; i++) if (adapter->xdp_ring[i]->xsk_umem) lead to panic. Call trace: [exception RIP: ixgbe_xdp+368] RIP: ffffffffc02a76a0 RSP: ffff9fe16202f8d0 RFLAGS: 00010297 RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000000000001c RDI: ffffffffa94ead90 RBP: ffff92f8f24c0c18 R8: 0000000000000000 R9: 0000000000000000 R10: ffff9fe16202f830 R11: 0000000000000000 R12: ffff92f8f24c0000 R13: ffff9fe16202fc01 R14: 000000000000000a R15: ffffffffc02a7530 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 7 [ffff9fe16202f8f0] dev_xdp_install at ffffffffa89fbbcc 8 [ffff9fe16202f920] dev_change_xdp_fd at ffffffffa8a08808 9 [ffff9fe16202f960] do_setlink at ffffffffa8a20235 10 [ffff9fe16202fa88] rtnl_setlink at ffffffffa8a20384 11 [ffff9fe16202fc78] rtnetlink_rcv_msg at ffffffffa8a1a8dd 12 [ffff9fe16202fcf0] netlink_rcv_skb at ffffffffa8a717eb 13 [ffff9fe16202fd40] netlink_unicast at ffffffffa8a70f88 14 [ffff9fe16202fd80] netlink_sendmsg at ffffffffa8a71319 15 [ffff9fe16202fdf0] sock_sendmsg at ffffffffa89df290 16 [ffff9fe16202fe08] __sys_sendto at ffffffffa89e19c8 17 [ffff9fe16202ff30] __x64_sys_sendto at ffffffffa89e1a64 18 [ffff9fe16202ff38] do_syscall_64 at ffffffffa84042b9 19 [ffff9fe16202ff50] entry_SYSCALL_64_after_hwframe at ffffffffa8c0008c Fixes: 4a9b32f30f80 ("ixgbe: fix potential RX buffer starvation for AF_XDP") Signed-off-by: Feng Zhou <redacted> --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 14aea40da50f..5db496cc5070 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c@@ -10112,6 +10112,7 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) struct ixgbe_adapter *adapter = netdev_priv(dev); struct bpf_prog *old_prog; bool need_reset; + int num_queues; if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) return -EINVAL;@@ -10161,11 +10162,14 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) /* Kick start the NAPI context if there is an AF_XDP socket open * on that queue id. This so that receiving will start. */ - if (need_reset && prog) - for (i = 0; i < adapter->num_rx_queues; i++) + if (need_reset && prog) { + num_queues = min_t(int, adapter->num_rx_queues, + adapter->num_xdp_queues); + for (i = 0; i < num_queues; i++) if (adapter->xdp_ring[i]->xsk_pool) (void)ixgbe_xsk_wakeup(adapter->netdev, i, XDP_WAKEUP_RX); + } return 0; }-- 2.11.0