From: Jiri Bohac jbohac@suse.cz
[ Upstream commit 6c015a2256801597fadcbc11d287774c9c512fa5 ]
__dev_alloc_name(), when supplied with a name containing '%d', will search for the first available device number to generate a unique device name.
Since commit ff92741270bf8b6e78aa885f166b68c7a67ab13a ("net: introduce name_node struct to be used in hashlist") network devices may have alternate names. __dev_alloc_name() does take these alternate names into account, possibly generating a name that is already taken and failing with -ENFILE as a result.
This demonstrates the bug:
# rmmod dummy 2>/dev/null # ip link property add dev lo altname dummy0 # modprobe dummy numdummies=1 modprobe: ERROR: could not insert 'dummy': Too many open files in system
Instead of creating a device named dummy1, modprobe fails.
Fix this by checking all the names in the d->name_node list, not just d->name.
Signed-off-by: Jiri Bohac jbohac@suse.cz Fixes: ff92741270bf ("net: introduce name_node struct to be used in hashlist") Reviewed-by: Jiri Pirko jiri@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/dev.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c index a5a1dbe66b76..541ee3bc467b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1182,6 +1182,18 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) return -ENOMEM;
for_each_netdev(net, d) { + struct netdev_name_node *name_node; + list_for_each_entry(name_node, &d->name_node->list, list) { + if (!sscanf(name_node->name, name, &i)) + continue; + if (i < 0 || i >= max_netdevices) + continue; + + /* avoid cases where sscanf is not exact inverse of printf */ + snprintf(buf, IFNAMSIZ, name, i); + if (!strncmp(buf, name_node->name, IFNAMSIZ)) + set_bit(i, inuse); + } if (!sscanf(d->name, name, &i)) continue; if (i < 0 || i >= max_netdevices)