[PATCH 5.5 030/151] sfc: detach from cb_page in efx_copy_channel()

From: Greg Kroah-Hartman
Date: Tue Mar 17 2020 - 07:07:57 EST


From: Edward Cree <ecree@xxxxxxxxxxxxxx>

[ Upstream commit 4b1bd9db078f7d5332c8601a2f5bd43cf0458fd4 ]

It's a resource, not a parameter, so we can't copy it into the new
channel's TX queues, otherwise aliasing will lead to resource-
management bugs if the channel is subsequently torn down without
being initialised.

Before the Fixes:-tagged commit there was a similar bug with
tsoh_page, but I'm not sure it's worth doing another fix for such
old kernels.

Fixes: e9117e5099ea ("sfc: Firmware-Assisted TSO version 2")
Suggested-by: Derek Shute <Derek.Shute@xxxxxxxxxxx>
Signed-off-by: Edward Cree <ecree@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/sfc/efx.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -525,6 +525,7 @@ efx_copy_channel(const struct efx_channe
if (tx_queue->channel)
tx_queue->channel = channel;
tx_queue->buffer = NULL;
+ tx_queue->cb_page = NULL;
memset(&tx_queue->txd, 0, sizeof(tx_queue->txd));
}