From: Michael Chan <michael.chan@broadcom.com> stable inclusion from stable-5.10.77 commit 2b7c5eed19d3009dd6cca36853b3a22d7eff9209 bugzilla: 185677 https://gitee.com/openeuler/kernel/issues/I4IAP7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 0c57eeecc559ca6bc18b8c4e2808bc78dbe769b0 upstream. Drivers call netdev_set_num_tc() and then netdev_set_tc_queue() to set the queue count and offset for each TC. So the queue count and offset for the TCs may be zero for a short period after dev->num_tc has been set. If a TX packet is being transmitted at this time in the code path netdev_pick_tx() -> skb_tx_hash(), skb_tx_hash() may see nonzero dev->num_tc but zero qcount for the TC. The while loop that keeps looping while hash >= qcount will not end. Fix it by checking the TC's qcount to be nonzero before using it. Fixes: eadec877ce9c ("net: Add support for subordinate traffic classes to netdev_pick_tx") Reviewed-by: Andy Gospodarek <gospo@broadcom.com> Signed-off-by: Michael Chan <michael.chan@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- net/core/dev.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 736972a8f981..51a3729f810b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3171,6 +3171,12 @@ static u16 skb_tx_hash(const struct net_device *dev, qoffset = sb_dev->tc_to_txq[tc].offset; qcount = sb_dev->tc_to_txq[tc].count; + if (unlikely(!qcount)) { + net_warn_ratelimited("%s: invalid qcount, qoffset %u for tc %u\n", + sb_dev->name, qoffset, tc); + qoffset = 0; + qcount = dev->real_num_tx_queues; + } } if (skb_rx_queue_recorded(skb)) { -- 2.20.1