6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jakub Kicinski kuba@kernel.org
[ Upstream commit d09486a04f5da0a812c26217213b89a3b1acf836 ]
Mark reports a BUG() when a net namespace is removed.
kernel BUG at net/core/dev.c:11520!
Physical interfaces moved outside of init_net get "refunded" to init_net when that namespace disappears. The main interface name may get overwritten in the process if it would have conflicted. We need to also discard all conflicting altnames. Recent fixes addressed ensuring that altnames get moved with the main interface, which surfaced this problem.
Reported-by: Марк Коренберг socketpair@gmail.com Link: https://lore.kernel.org/all/CAEmTpZFZ4Sv3KwqFOY2WKDHeZYdi0O7N5H1nTvcGp=SAEav... Fixes: 7663d522099e ("net: check for altname conflicts when changing netdev's netns") Signed-off-by: Jakub Kicinski kuba@kernel.org Reviewed-by: Eric Dumazet edumazet@google.com Reviewed-by: Jiri Pirko jiri@nvidia.com Reviewed-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/dev.c | 9 +++++++++ net/core/dev.h | 3 +++ 2 files changed, 12 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c index 0a5566b6f8a2..1ba3662faf0a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -11323,6 +11323,7 @@ static struct pernet_operations __net_initdata netdev_net_ops = {
static void __net_exit default_device_exit_net(struct net *net) { + struct netdev_name_node *name_node, *tmp; struct net_device *dev, *aux; /* * Push all migratable network devices back to the @@ -11345,6 +11346,14 @@ static void __net_exit default_device_exit_net(struct net *net) snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex); if (netdev_name_in_use(&init_net, fb_name)) snprintf(fb_name, IFNAMSIZ, "dev%%d"); + + netdev_for_each_altname_safe(dev, name_node, tmp) + if (netdev_name_in_use(&init_net, name_node->name)) { + netdev_name_node_del(name_node); + synchronize_rcu(); + __netdev_name_node_alt_destroy(name_node); + } + err = dev_change_net_namespace(dev, &init_net, fb_name); if (err) { pr_emerg("%s: failed to move %s to init_net: %d\n", diff --git a/net/core/dev.h b/net/core/dev.h index 9ca91457c197..db9ff8cd8d46 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -63,6 +63,9 @@ int dev_change_name(struct net_device *dev, const char *newname);
#define netdev_for_each_altname(dev, namenode) \ list_for_each_entry((namenode), &(dev)->name_node->list, list) +#define netdev_for_each_altname_safe(dev, namenode, next) \ + list_for_each_entry_safe((namenode), (next), &(dev)->name_node->list, \ + list)
int netdev_name_node_alt_create(struct net_device *dev, const char *name); int netdev_name_node_alt_destroy(struct net_device *dev, const char *name);