linux-kernel - [PATCH net-next v2 5/6] hv_netvsc: synchronize netvsc_change_mtu()/netvsc_set_channels() with netvsc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1463140525-27338-6-git-send-email-vkuznets@redhat.com>
Date:	Fri, 13 May 2016 13:55:24 +0200
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	netdev@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, devel@...uxdriverproject.org,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	"Lino Sanfilippo" <LinoSanfilippo@....de>
Subject: [PATCH net-next v2 5/6] hv_netvsc: synchronize netvsc_change_mtu()/netvsc_set_channels() with netvsc_remove()

When netvsc device is removed during mtu change or channels setup we get
into troubles as both paths are trying to remove the device. Synchronize
them with start_remove flag and rtnl lock.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 drivers/net/hyperv/netvsc_drv.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 7325d69..6a69b5c 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -759,7 +759,7 @@ static int netvsc_set_channels(struct net_device *net,
 	int ret = 0;
 	bool recovering = false;
 
-	if (!nvdev || nvdev->destroy)
+	if (net_device_ctx->start_remove || !nvdev || nvdev->destroy)
 		return -ENODEV;
 
 	num_chn = nvdev->num_chn;
@@ -907,7 +907,7 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 	u32 num_chn;
 	int ret = 0;
 
-	if (nvdev == NULL || nvdev->destroy)
+	if (ndevctx->start_remove || !nvdev || nvdev->destroy)
 		return -ENODEV;
 
 	if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
@@ -1445,7 +1445,12 @@ static int netvsc_remove(struct hv_device *dev)
 	ndev_ctx = netdev_priv(net);
 	net_device = ndev_ctx->nvdev;
 
+	/* Avoid racing with netvsc_change_mtu()/netvsc_set_channels()
+	 * removing the device.
+	 */
+	rtnl_lock();
 	ndev_ctx->start_remove = true;
+	rtnl_unlock();
 
 	cancel_delayed_work_sync(&ndev_ctx->dwork);
 	cancel_work_sync(&ndev_ctx->work);
-- 
2.5.5