bonding: fix two race conditions in bond_store_updelay/downdelay
authorNikolay Aleksandrov <nikolay@redhat.com>
Wed, 13 Nov 2013 16:07:46 +0000 (17:07 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 8 Dec 2013 15:29:24 +0000 (07:29 -0800)
[ Upstream commit b869ccfab1e324507fa3596e3e1308444fb68227 ]

This patch fixes two race conditions between bond_store_updelay/downdelay
and bond_store_miimon which could lead to division by zero as miimon can
be set to 0 while either updelay/downdelay are being set and thus miss the
zero check in the beginning, the zero div happens because updelay/downdelay
are stored as new_value / bond->params.miimon. Use rtnl to synchronize with
miimon setting.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: Veaceslav Falico <vfalico@redhat.com>
Acked-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/bonding/bond_sysfs.c

index 50ddeb9..a88d04b 100644 (file)
@@ -697,6 +697,8 @@ static ssize_t bonding_store_downdelay(struct device *d,
        int new_value, ret = count;
        struct bonding *bond = to_bond(d);
 
+       if (!rtnl_trylock())
+               return restart_syscall();
        if (!(bond->params.miimon)) {
                pr_err("%s: Unable to set down delay as MII monitoring is disabled\n",
                       bond->dev->name);
@@ -730,6 +732,7 @@ static ssize_t bonding_store_downdelay(struct device *d,
        }
 
 out:
+       rtnl_unlock();
        return ret;
 }
 static DEVICE_ATTR(downdelay, S_IRUGO | S_IWUSR,
@@ -752,6 +755,8 @@ static ssize_t bonding_store_updelay(struct device *d,
        int new_value, ret = count;
        struct bonding *bond = to_bond(d);
 
+       if (!rtnl_trylock())
+               return restart_syscall();
        if (!(bond->params.miimon)) {
                pr_err("%s: Unable to set up delay as MII monitoring is disabled\n",
                       bond->dev->name);
@@ -785,6 +790,7 @@ static ssize_t bonding_store_updelay(struct device *d,
        }
 
 out:
+       rtnl_unlock();
        return ret;
 }
 static DEVICE_ATTR(updelay, S_IRUGO | S_IWUSR,