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authorFelix Jia <felix.jia@alliedtelesis.co.nz>2017-02-27 12:41:23 +1300
committerDavid S. Miller <davem@davemloft.net>2017-03-01 10:22:48 -0800
commit8c171d6ca56c6891372a97af26b58b2cfad7fd9a (patch)
tree13aaa3cbaebb1e12014a986f9f5e2c7c944501b1 /net
parenta3695e9751b3c616170b552f8561b5a7c5b7a3ca (diff)
net/ipv6: avoid possible dead locking on addr_gen_mode sysctl
The addr_gen_mode variable can be accessed by both sysctl and netlink. Repleacd rtnl_lock() with rtnl_trylock() protect the sysctl operation to avoid the possbile dead lock.` Signed-off-by: Felix Jia <felix.jia@alliedtelesis.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/addrconf.c22
1 files changed, 15 insertions, 7 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 3a2025f5bf2c..cfc485a8e1c0 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5692,13 +5692,18 @@ static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
struct inet6_dev *idev = (struct inet6_dev *)ctl->extra1;
struct net *net = (struct net *)ctl->extra2;
+ if (!rtnl_trylock())
+ return restart_syscall();
+
ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
if (write) {
new_val = *((int *)ctl->data);
- if (check_addr_gen_mode(new_val) < 0)
- return -EINVAL;
+ if (check_addr_gen_mode(new_val) < 0) {
+ ret = -EINVAL;
+ goto out;
+ }
/* request for default */
if (&net->ipv6.devconf_dflt->addr_gen_mode == ctl->data) {
@@ -5707,20 +5712,23 @@ static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
/* request for individual net device */
} else {
if (!idev)
- return ret;
+ goto out;
- if (check_stable_privacy(idev, net, new_val) < 0)
- return -EINVAL;
+ if (check_stable_privacy(idev, net, new_val) < 0) {
+ ret = -EINVAL;
+ goto out;
+ }
if (idev->cnf.addr_gen_mode != new_val) {
idev->cnf.addr_gen_mode = new_val;
- rtnl_lock();
addrconf_dev_config(idev->dev);
- rtnl_unlock();
}
}
}
+out:
+ rtnl_unlock();
+
return ret;
}