Commit bf17b36c authored by Johannes Berg's avatar Johannes Berg Committed by Jakub Kicinski
Browse files

net: sysfs: fix locking in carrier read 



My previous patch added a call to linkwatch_sync_dev(),
but that of course needs to be called under RTNL, which
I missed earlier, but now saw RCU warnings from.

Fix that by acquiring the RTNL in a similar fashion to
how other files do it here.

Fixes: facd15df ("net: core: synchronize link-watch when carrier is queried")
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20231206172122.859df6ba937f.I9c80608bcfbab171943ff4942b52dbd5e97fe06e@changeid


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 172db56d

net/core/net-sysfs.c

+7 −2
Original line number Diff line number Diff line
@@ -193,6 +193,10 @@ static ssize_t carrier_show(struct device *dev, 
			    struct device_attribute *attr, char *buf)

{

	struct net_device *netdev = to_net_dev(dev);

	int ret = -EINVAL;



	if (!rtnl_trylock())

		return restart_syscall();



	if (netif_running(netdev)) {

		/* Synchronize carrier state with link watch,
@@ -200,10 +204,11 @@ static ssize_t carrier_show(struct device *dev, 
		 */

		linkwatch_sync_dev(netdev);



		return sysfs_emit(buf, fmt_dec, !!netif_carrier_ok(netdev));

		ret = sysfs_emit(buf, fmt_dec, !!netif_carrier_ok(netdev));

	}

	rtnl_unlock();



	return -EINVAL;

	return ret;

}

static DEVICE_ATTR_RW(carrier);