Linux will soon also be protected from the Retbleed vulnerability

Linux will soon also be protected from the Retbleed vulnerability

After Meltdown and Specter, another very serious vulnerability was recently discovered that uses branch target injection to intercept information on modern processors. Called Retbleed, this flaw can affect AMD Zen, Zen + and Zen 2 processors (aka Ryzen 1000, 2000, 2000G, 3000, 3000G, and 4000G), and Intel Skylake, Kaby Lake Coffee Lake (aka Intel Core 6000 CPUs) , 7000, 8000 and 9000).

As happened years ago, the major manufacturers have all taken action to offer mitigations, both in terms of firmware updates of motherboards, and of the main operating systems in circulation (leading to a possible decrease in performance).

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When we have one of these embargoed [hardware] problems, the patches have not been developed openly and consequently have not been subjected to the usual correctness check by all infrastructures automation and testing we have. So it is not surprising: even afterwards there were various small patches of correction for some special cases.

Last week there were other development trees that independently asked for an extension, so 5.19 will be one of those releases that will have an additional rc8 next weekend before the final release. When it rains, it rains. Not that things are that bad. I believe the aftermath of Retbleed have been handled best.

In addition to the mitigations for Redbleed, the other two development trees that have taken the longest are the btrfs filesystem and firmware for Intel GPU controllers which sometimes unintentionally disabled graphics boosters on some new Intel Alder Lake processors. Torvalds reported that both problems appear to have been fixed.

So, barring any last-minute problems, the Linux 5.19 kernel will be available next week. The later version (5.2) could be chosen as a long term support release.