K 10
svn:author
V 2
mw
K 8
svn:date
V 27
2023-07-31T12:57:25.196439Z
K 7
svn:log
V 1180
ena: Initialize statistics before the interface is available

In [1], the FBSD community exposed a bug in the fbsd/ena driver.

Bug description:
----------------
Current function call order is as follows:

1. ena_attach()
1.1. ena_setup_ifnet()
1.1.1. Registration of ena_get_counter()
1.1.2. ether_ifattach(ifp, adapter->mac_addr);
1.2. Statistics allocation and initialization.

At point 1.1.2, when ether_ifattach() returns, the interface is available,
and stats can be read before they are allocated, leading to kernel panic.

Also fixed a potential memory leak by freeing the stats since they were
not freed in case the following calls failed.

Fix:
----
This commit moves the statistics allocation and initialization to happen
before ena_setup_ifnet()

[1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=268934

Fixes: 9b8d05b8ac78 ("Add support for Amazon Elastic Network Adapter (ENA) NIC")
Fixes: 30217e2dff10 ("Rework counting of hardware statistics in ENA driver")
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit b9e80b5280b75f2c641d680245df44b8ff26a7b0)

Git Hash:   383cf7052a29ab3f4d1bdffb888696546e4f0fe4
Git Author: osamaabb@amazon.com
END