net-sysfs: Use rtnl_trylock in sysfs methods.
The earlier patch to fix the deadlock between a network device going
away and writing to sysfs attributes was incomplete.
- It did not set signal_pending so we would leak ERSTARTSYS to user space.
- It used ERESTARTSYS which only restarts if sigaction configures it to.
- It did not cover store and show for ifalias.
So fix all of these up and use the new helper restart_syscall so we get
the details correct on what it takes.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 2da59a0..b9641e8 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -78,7 +78,7 @@
goto err;
if (!rtnl_trylock())
- return -ERESTARTSYS;
+ return restart_syscall();
if (dev_isalive(net)) {
if ((ret = (*set)(net, new)) == 0)
@@ -225,7 +225,8 @@
if (len > 0 && buf[len - 1] == '\n')
--count;
- rtnl_lock();
+ if (!rtnl_trylock())
+ return restart_syscall();
ret = dev_set_alias(netdev, buf, count);
rtnl_unlock();
@@ -238,7 +239,8 @@
const struct net_device *netdev = to_net_dev(dev);
ssize_t ret = 0;
- rtnl_lock();
+ if (!rtnl_trylock())
+ return restart_syscall();
if (netdev->ifalias)
ret = sprintf(buf, "%s\n", netdev->ifalias);
rtnl_unlock();