[PATCH net] netvsc: fix race during initialization
From: Stephen Hemminger <stephen@networkplumber.org>
Date: 2017-03-16 19:48:21
Subsystem:
hyper-v/azure core and drivers, networking drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
When device is being setup on boot, there is a small race where
network device callback is registered, but the netvsc_device pointer
is not set yet. This can cause a NULL ptr dereference if packet
arrives during this window.
Fixes: 46b4f7f5d1f7 ("netvsc: eliminate per-device outstanding send counter")
Signed-off-by: Stephen Hemminger <redacted>
---
Applies to 4.11 only, not in earlier versions.
net-next needs different patch
drivers/net/hyperv/netvsc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 4c1d8cca247b..8dd0b8770328 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c@@ -1231,8 +1231,11 @@ void netvsc_channel_cb(void *context) return; net_device = net_device_to_netvsc_device(ndev); - if (unlikely(net_device->destroy) && - netvsc_channel_idle(net_device, q_idx)) + if (unlikely(!net_device)) + return; + + if (unlikely(net_device->destroy && + netvsc_channel_idle(net_device, q_idx))) return; /* commit_rd_index() -> hv_signal_on_read() needs this. */
--
2.11.0