From 496a60cdcd5d0d884dddf6c3b4ea912923a70f13 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 13 May 2009 17:02:50 +0000
Subject: [PATCH] net: FIX bonding sysfs rtnl_lock deadlock
Sysfs files for a network device can not unconditionally take the
rtnl_lock as the bonding sysfs files do. If someone accesses those
sysfs files while the network device is being unregistered with the
rtnl_lock held we will deadlock.
So use trylock and restart_syscall to avoid this problem.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/bonding/bond_sysfs.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index d28731535226..3a1b7b04eb79 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -251,7 +251,8 @@ static ssize_t bonding_store_slaves(struct device *d,
/* Note: We can't hold bond->lock here, as bond_create grabs it. */
- rtnl_lock();
+ if (!rtnl_trylock())
+ return restart_syscall();
down_write(&(bonding_rwsem));
sscanf(buffer, "%16s", command); /* IFNAMSIZ*/
@@ -1171,7 +1172,8 @@ static ssize_t bonding_store_primary(struct device *d,
struct slave *slave;
struct bonding *bond = to_bond(d);
- rtnl_lock();
+ if (!rtnl_trylock())
+ return restart_syscall();
read_lock(&bond->lock);
write_lock_bh(&bond->curr_slave_lock);
@@ -1288,7 +1290,8 @@ static ssize_t bonding_store_active_slave(struct device *d,
struct slave *new_active = NULL;
struct bonding *bond = to_bond(d);
- rtnl_lock();
+ if (!rtnl_trylock())
+ return restart_syscall();
read_lock(&bond->lock);
write_lock_bh(&bond->curr_slave_lock);
--
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