| From | Luis Henriques <> | Subject | [PATCH 3.11 016/208] bonding: fix two race conditions in bond_store_updelay/downdelay | Date | Thu, 19 Dec 2013 11:51:54 +0000 |
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3.11.10.2 -stable review patch. If anyone has any objections, please let me know.
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From: Nikolay Aleksandrov <nikolay@redhat.com>
commit b869ccfab1e324507fa3596e3e1308444fb68227 upstream.
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 <fubar@us.ibm.com> CC: Andy Gospodarek <andy@greyhouse.net> CC: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> Acked-by: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- 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 076f8af..ee7a5ee 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -733,6 +733,8 @@ 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); @@ -766,6 +768,7 @@ static ssize_t bonding_store_downdelay(struct device *d, } out: + rtnl_unlock(); return ret; } static DEVICE_ATTR(downdelay, S_IRUGO | S_IWUSR, @@ -788,6 +791,8 @@ 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); @@ -821,6 +826,7 @@ static ssize_t bonding_store_updelay(struct device *d, } out: + rtnl_unlock(); return ret; } static DEVICE_ATTR(updelay, S_IRUGO | S_IWUSR, -- 1.8.3.2
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