From 336ca57c3b4e2b58ea3273e6d978ab3dfa387b4c Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 13 May 2009 16:57:25 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/core/net-sysfs.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 2da59a0ac4ac..b9641e816eee 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -78,7 +78,7 @@ static ssize_t netdev_store(struct device *dev, struct device_attribute *attr, goto err; if (!rtnl_trylock()) - return -ERESTARTSYS; + return restart_syscall(); if (dev_isalive(net)) { if ((ret = (*set)(net, new)) == 0) @@ -225,7 +225,8 @@ static ssize_t store_ifalias(struct device *dev, struct device_attribute *attr, 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 @@ static ssize_t show_ifalias(struct device *dev, 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();