From ea6836dd7ef9cfbed5dce421190009f9eed00b7e Mon Sep 17 00:00:00 2001 From: "nikolay@redhat.com" Date: Sat, 18 May 2013 01:18:28 +0000 Subject: [PATCH] bonding: fix set mode race conditions Changing the mode without any locking can result in multiple races (e.g. upping a bond, enslaving/releasing). Depending on which race is hit the impact can vary from incosistent bond state to kernel crash. Use RTNL to synchronize the mode setting with the dangerous races. Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- drivers/net/bonding/bond_sysfs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c index ea7a388f4843..77ea237de900 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -316,6 +316,9 @@ static ssize_t bonding_store_mode(struct device *d, int new_value, ret = count; struct bonding *bond = to_bond(d); + if (!rtnl_trylock()) + return restart_syscall(); + if (bond->dev->flags & IFF_UP) { pr_err("unable to update mode of %s because interface is up.\n", bond->dev->name); @@ -352,6 +355,7 @@ static ssize_t bonding_store_mode(struct device *d, bond->dev->name, bond_mode_tbl[new_value].modename, new_value); out: + rtnl_unlock(); return ret; } static DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, -- 2.20.1