net: Fix bridgeing sysfs handling of rtnl_lock

Holding rtnl_lock when we are unregistering the sysfs files can
deadlock if we unconditionally take rtnl_lock in a sysfs file.  So fix
it with the now familiar patter of: rtnl_trylock and syscall_restart()

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 603d89248e7148e1a830146953dfbfdcb54491bd..ee4820aa1843ee5e54c1b677f4cd5875a440d442 100644 (file)
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -172,7 +172,8 @@ static ssize_t store_stp_state(struct device *d,
        if (endp == buf)
                return -EINVAL;
 
-       rtnl_lock();
+       if (!rtnl_trylock())
+               return restart_syscall();
        br_stp_set_enabled(br, val);
        rtnl_unlock();
 

diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 02b2d50cce4da640f4b62a6652253d217e890af2..4a3cdf8f38131e6b19adf330a0e697a307a39e16 100644 (file)
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -189,7 +189,8 @@ static ssize_t brport_store(struct kobject * kobj,
 
        val = simple_strtoul(buf, &endp, 0);
        if (endp != buf) {
-               rtnl_lock();
+               if (!rtnl_trylock())
+                       return restart_syscall();
                if (p->dev && p->br && brport_attr->store) {
                        spin_lock_bh(&p->br->lock);
                        ret = brport_attr->store(p, val);