diff options
| author | Jeff Dike <jdike@akamai.com> | 2020-12-22 21:54:21 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-12 19:49:02 +0100 |
| commit | df2799188642fdffece3e74a32b9b70e336899f6 (patch) | |
| tree | 47a33394fc9e422b25e5908f6218e7f0074503b7 | |
| parent | 586692be691c9955b277219b8a8f8559594b391a (diff) | |
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 7118b8263760..a3447f8eaf66 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1357,14 +1357,16 @@ 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; } |