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Message-Id: <20170419222202.17992-1-sthemmin@microsoft.com>
Date: Wed, 19 Apr 2017 15:22:02 -0700
From: Stephen Hemminger <stephen@...workplumber.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, Stephen Hemminger <sthemmin@...rosoft.com>
Subject: [PATCH net-next] netvsc: fix use after free on module removal
The NAPI data structure is embedded in the netvsc_device structure
and is freed when device is closed. There is still a reference
(in NAPI list) to this which causes a crash in netif_napi_del
when device is removed. Fix by managing NAPI instances correctly.
Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
---
Note: resend with correct list address
drivers/net/hyperv/netvsc.c | 9 +++++----
drivers/net/hyperv/rndis_filter.c | 9 ++++++---
2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index fd21d5aab580..e282bdff7aa0 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -568,8 +568,9 @@ void netvsc_device_remove(struct hv_device *device)
/* Now, we can close the channel safely */
vmbus_close(device->channel);
+ /* And dissassociate NAPI context from device */
for (i = 0; i < net_device->num_chn; i++)
- napi_disable(&net_device->chan_table[i].napi);
+ netif_napi_del(&net_device->chan_table[i].napi);
/* Release all resources */
free_netvsc_device_rcu(net_device);
@@ -1304,8 +1305,6 @@ int netvsc_device_add(struct hv_device *device,
struct netvsc_channel *nvchan = &net_device->chan_table[i];
nvchan->channel = device->channel;
- netif_napi_add(ndev, &nvchan->napi,
- netvsc_poll, NAPI_POLL_WEIGHT);
}
/* Open the channel */
@@ -1323,6 +1322,8 @@ int netvsc_device_add(struct hv_device *device,
netdev_dbg(ndev, "hv_netvsc channel opened successfully\n");
/* Enable NAPI handler for init callbacks */
+ netif_napi_add(ndev, &net_device->chan_table[0].napi,
+ netvsc_poll, NAPI_POLL_WEIGHT);
napi_enable(&net_device->chan_table[0].napi);
/* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
@@ -1341,7 +1342,7 @@ int netvsc_device_add(struct hv_device *device,
return ret;
close:
- napi_disable(&net_device->chan_table[0].napi);
+ netif_napi_del(&net_device->chan_table[0].napi);
/* Now, we can close the channel safely */
vmbus_close(device->channel);
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 1e9445bc4539..ab92c3c95951 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1009,13 +1009,16 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
/* Set the channel before opening.*/
nvchan->channel = new_sc;
+ netif_napi_add(ndev, &nvchan->napi,
+ netvsc_poll, NAPI_POLL_WEIGHT);
ret = vmbus_open(new_sc, nvscdev->ring_size * PAGE_SIZE,
nvscdev->ring_size * PAGE_SIZE, NULL, 0,
netvsc_channel_cb, nvchan);
-
-
- napi_enable(&nvchan->napi);
+ if (ret == 0)
+ napi_enable(&nvchan->napi);
+ else
+ netdev_err(ndev, "sub channel open failed (%d)\n", ret);
if (refcount_dec_and_test(&nvscdev->sc_offered))
complete(&nvscdev->channel_init_wait);
--
2.11.0
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