From b869ccfab1e324507fa3596e3e1308444fb68227 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Wed, 13 Nov 2013 17:07:46 +0100 Subject: [PATCH] bonding: fix two race conditions in bond_store_updelay/downdelay 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. CC: Jay Vosburgh CC: Andy Gospodarek CC: Veaceslav Falico Signed-off-by: Nikolay Aleksandrov Acked-by: Veaceslav Falico Signed-off-by: David S. Miller --- drivers/net/bonding/bond_sysfs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c index 6245d92b7a0c..9f32e2304004 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -702,6 +702,8 @@ 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); @@ -735,6 +737,7 @@ static ssize_t bonding_store_downdelay(struct device *d, } out: + rtnl_unlock(); return ret; } static DEVICE_ATTR(downdelay, S_IRUGO | S_IWUSR, @@ -757,6 +760,8 @@ 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); @@ -790,6 +795,7 @@ static ssize_t bonding_store_updelay(struct device *d, } out: + rtnl_unlock(); return ret; } static DEVICE_ATTR(updelay, S_IRUGO | S_IWUSR, -- 2.20.1