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| author | Jeff Dike <jdike@akamai.com> | 2020-12-22 21:54:21 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-12 20:09:07 +0100 |
| commit | f6870be9f527d76af5ec4968998606eb1de5c86d (patch) | |
| tree | 7fdb6685617b93eabebe2a97d328984dcb7d26c5 | |
| parent | a33ad046cae9566dbadfebe19ef0d1ac128d2b0e (diff) | |
| download | linux-f6870be9f527d76af5ec4968998606eb1de5c86d.tar.gz linux-f6870be9f527d76af5ec4968998606eb1de5c86d.tar.bz2 linux-f6870be9f527d76af5ec4968998606eb1de5c86d.zip | |
virtio_net: Fix recursive call to cpus_read_lock()
[ Upstream commit de33212f768c5d9e2fe791b008cb26f92f0aa31c ]
virtnet_set_channels can recursively call cpus_read_lock if CONFIG_XPS
and CONFIG_HOTPLUG are enabled.
The path is:
virtnet_set_channels - calls get_online_cpus(), which is a trivial
wrapper around cpus_read_lock()
netif_set_real_num_tx_queues
netif_reset_xps_queues_gt
netif_reset_xps_queues - calls cpus_read_lock()
This call chain and potential deadlock happens when the number of TX
queues is reduced.
This commit the removes netif_set_real_num_[tr]x_queues calls from
inside the get/put_online_cpus section, as they don't require that it
be held.
Fixes: 47be24796c13 ("virtio-net: fix the set affinity bug when CPU IDs are not consecutive")
Signed-off-by: Jeff Dike <jdike@akamai.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20201223025421.671-1-jdike@akamai.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/virtio_net.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 0b457c81c448..2d2a307c0231 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1788,14 +1788,16 @@ static int virtnet_set_channels(struct net_device *dev, get_online_cpus(); err = _virtnet_set_queues(vi, queue_pairs); - if (!err) { - netif_set_real_num_tx_queues(dev, queue_pairs); - netif_set_real_num_rx_queues(dev, queue_pairs); - - virtnet_set_affinity(vi); + if (err) { + put_online_cpus(); + goto err; } + virtnet_set_affinity(vi); put_online_cpus(); + netif_set_real_num_tx_queues(dev, queue_pairs); + netif_set_real_num_rx_queues(dev, queue_pairs); + err: return err; } |