2 files changed, 20 insertions, 3 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 040c4f05b653..26dec2be9615 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1317,14 +1317,19 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write,
 {
         int *valp = ctl->data;
         int val = *valp;
+        loff_t pos = *ppos;
         int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
         if (write && *valp != val) {
                 struct net *net = ctl->extra2;
 
                 if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
-                        if (!rtnl_trylock())
+                        if (!rtnl_trylock()) {
+                                /* Restore the original values before restarting */
+                                *valp = val;
+                                *ppos = pos;
                                 return restart_syscall();
+                        }
                         if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
                                 inet_forward_change(net);
                         } else if (*valp) {
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index de7a194a64ab..143791da062c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -502,8 +502,11 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old)
         if (p == &net->ipv6.devconf_dflt->forwarding)
                 return 0;
 
-        if (!rtnl_trylock())
+        if (!rtnl_trylock()) {
+                /* Restore the original values before restarting */
+                *p = old;
                 return restart_syscall();
+        }
 
         if (p == &net->ipv6.devconf_all->forwarding) {
                 __s32 newf = net->ipv6.devconf_all->forwarding;
@@ -4028,12 +4031,15 @@ int addrconf_sysctl_forward(ctl_table *ctl, int write,
 {
         int *valp = ctl->data;
         int val = *valp;
+        loff_t pos = *ppos;
         int ret;
 
         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
         if (write)
                 ret = addrconf_fixup_forwarding(ctl, valp, val);
+        if (ret)
+                *ppos = pos;
         return ret;
 }
 
@@ -4075,8 +4081,11 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old)
         if (p == &net->ipv6.devconf_dflt->disable_ipv6)
                 return 0;
 
-        if (!rtnl_trylock())
+        if (!rtnl_trylock()) {
+                /* Restore the original values before restarting */
+                *p = old;
                 return restart_syscall();
+        }
 
         if (p == &net->ipv6.devconf_all->disable_ipv6) {
                 __s32 newf = net->ipv6.devconf_all->disable_ipv6;
@@ -4095,12 +4104,15 @@ int addrconf_sysctl_disable(ctl_table *ctl, int write,
 {
         int *valp = ctl->data;
         int val = *valp;
+        loff_t pos = *ppos;
         int ret;
 
         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
         if (write)
                 ret = addrconf_disable_ipv6(ctl, valp, val);
+        if (ret)
+                *ppos = pos;
         return ret;
 }