tree 4a0c4bd707bf32ee2b72f6574906b4847bebbb51
parent b399a3944d53fb8f39b202da9830e8daa1336e19
author Netanel Belgazal <netanel@amazon.com> 1511114620 +0000
committer David S. Miller <davem@davemloft.net> 1511145316 +0900

net: ena: fix race condition between device reset and link up setup

In rare cases, ena driver would reset and re-start the device,
for example, in case of misbehaving application that causes
transmit timeout

The first step in the reset procedure is to stop the Tx traffic by
calling ena_carrier_off().

After the driver have just started the device reset procedure, device
happens to send an asynchronous notification (via AENQ) to the driver
than there was a link change (to link-up state).
This link change is mapped to a call to netif_carrier_on() which
re-activates the Tx queues, violating the assumption of no tx traffic
until device reset is completed, as the reset task might still be in
the process of queues initialization, leading to an access to
uninitialized memory.

Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>