Messages in this thread |  | | Date | Wed, 3 Jan 2024 14:22:23 -0800 | | From | "Paul E. McKenney" <> | | Subject | [BUG] Guest OSes die simultaneously (bisected) |
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Hello!
Since some time between v5.19 and v6.4, long-running rcutorture tests would (rarely but intolerably often) have all guests on a given host die simultaneously with something like an instruction fault or a segmentation violation.
Each bisection step required 20 hosts running 10 hours each, and this eventually fingered commit c59a1f106f5c ("KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS"). Although this commit is certainly messing with things that could possibly cause all manner of mischief, I don't immediately see a smoking gun. Except that the commit prior to this one is rock solid.
Just to make things a bit more exciting, bisection in mainline proved to be problematic due to bugs of various kinds that hid this one. I was therefore forced to bisect among the commits backported to the internal v5.19-based kernel, which fingered the backported version of the patch called out above.
Please note that this is not (yet) an emergency. I will just continue to run rcutorture on v5.19-based hypervisors in the meantime.
Any suggestions for debugging or fixing?
Thanx, Paul
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