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| author | Michael Chan <michael.chan@broadcom.com> | 2021-10-25 05:05:28 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-02 18:26:45 +0100 |
| commit | 02302cbd52264337630a32848ac03648648e9685 (patch) | |
| tree | 9bcea691a74e82919915e7f075b11f0c2699c4a6 | |
| parent | fbf150b16a3635634b7dfb7f229d8fcd643c6c51 (diff) | |
| download | linux-02302cbd52264337630a32848ac03648648e9685.tar.gz linux-02302cbd52264337630a32848ac03648648e9685.tar.bz2 linux-02302cbd52264337630a32848ac03648648e9685.zip | |
net: Prevent infinite while loop in skb_tx_hash()
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>
| -rw-r--r-- | net/core/dev.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index a6798117bb1a..397bc2f50de0 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2846,6 +2846,12 @@ 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)) { |