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>
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index d287315..3a1b7b0 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -251,7 +251,8 @@
/* 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 @@
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 @@
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);