[Bug 1987924] [NEW] GRUB may execute the kernel w/ dirty instruction cache on arm64

[Launchpad Bug Tracker]

You have been subscribed to a public bug by Julian Andres Klode (juliank):

[Impact]
Similar to bug 1987541, where shim may execute GRUB w/ polluted instruction cache, GRUB itself also fails to flush the instruction cache for the kernel memory before starting it. This is believed to be the source of some rare crashes seen executing instructions in the kernel EFI stub.

[Test Case]
Put an arm64 server in a reboot loop and watch for a crash (synchronous exception abort) after GRUB has started executing the kernel.

[Fix]
https://github.com/rhboot/grub2/pull/107

[What could go wrong]
The only risk I can identify is possibly-measurable performance impact to booting the kernel.

** Affects: grub2-unsigned (Ubuntu)
     Importance: Undecided
     Assignee: dann frazier (dannf)
         Status: Fix Released

** Affects: grub2-unsigned (Ubuntu Bionic)
     Importance: Undecided
         Status: New

** Affects: grub2-unsigned (Ubuntu Focal)
     Importance: Undecided
         Status: New

** Affects: grub2-unsigned (Ubuntu Jammy)
     Importance: Undecided
         Status: New

** Affects: grub2-unsigned (Ubuntu Kinetic)
     Importance: Undecided
     Assignee: dann frazier (dannf)
         Status: Fix Released


** Tags: foundations-triage-discuss
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GRUB may execute the kernel w/ dirty instruction cache on arm64 
https://bugs.launchpad.net/bugs/1987924
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