Following the July disclosure of the Retbleed CPU security vulnerability affecting older processors and an AMD change made in August, here is a fresh look at the performance impact of the Retbleed mitigations on Linux, including if opting for the IBPB-based Retbleed mitigation, and the accumulated CPU security mitigation impact for Zen 2 with the flagship Ryzen 9 3950X processor. . Being curious about the Retbleed performance impact for the Ryzen 9 3950X following my earlier Zen 1 testing as well as Intel Skylake testing, I ran some benchmarks looking at the AMD Ryzen 9 3950X in different mitigation states with the latest kernel code. As a reminder, Retbleed on the AMD side affects only Zen 2 CPUs and older -- not current generation Zen 3 or the upcoming Zen 4 processors. The link for this article located at Phoronix is no longer available. . Retbleed is a vulnerability in modern processors such as AMD Ryzen, allowing possible information leakage. AMD's patches, however, may sacrifice performance for enhanced security. Retbleed Mitigation,Ryzen 9 3950X Performance,AMD CPU Security,Zen 2 Mitigation Effects,CPU Threat Evaluations. . LinuxSecurity.com Team
Linus Torvalds says Retbleed has been addressed in the Linux kernel, but code complexity means the release will be delayed by a week to give more time for testing. . Linux kernel developers have successfully addressed Retbleed, the latest Spectre-like speculative execution attack against older AMD and Intel processors, Linus Torvalds wrote in a message to the Linux Kernel Mailing List on Sunday. However, the difficult repair process means there will be a delay of the release for Linux version 5.19 by a week. "I think we've got the retbleed fallout all handled (knock wood)," Torvalds wrote . The complexity of the fix wasn't the only reason for the release; there were two other development trees that independently asked for an extension. The other trees that needed the extension involve the btrfs filesystems and firmware for Intel GPU controllers. . Kernel engineers successfully addressed the Retbleed issue but postponed the release for additional testing because of the intricate nature of the fixes and additional components required.. Retbleed Fix, Linux Kernel Update, Speculative Attack Mitigation. . Brittany Day
Linux kernel developers have addressed the Retbleed speculative execution bug in older Intel and AMD silicon, but the fix wasn't straightforward, so emperor penguin Linus Torvalds has delayed delivery of the next version by a week. . "When we've had one of those embargoed [hardware] issues pending, the patches didn't get the open development, and then as a result missed all the usual sanity checking by all the automation build and test infrastructure we have," Torvalds wrote in a post announcing the delivery of release candidate seven for version 5.19 of the kernel. "So no surprise – there's been various small fixup patches afterwards too for some corner cases." . Core OS engineers tackled the Spectre variant vulnerability affecting legacy Intel and AMD processors, implementing patches in the latest beta version.. Retbleed Chip Flaw, Linux Kernel Update, Intel AMD Security Fix. . Brittany Day
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