From: p.pisati@gmail.com (Paolo Pisati)
To: linux-arm-kernel@lists.infradead.org
Subject: Internal error: Oops - BUG() / kvm boot race - arm64 kpti patchset related
Date: Wed, 28 Feb 2018 16:45:23 +0100 [thread overview]
Message-ID: <20180228154523.GA29931@akinoame> (raw)
Reproducible on 4.16-rc3 and 4.4.20 using defconfig - the failure it's
intermittent, but i could reproduce it 100% if i boot loop the kvm instance
(it usually shows up in less than 10 iterations but i tested 32 boots before
marking it good).
I bisected it down to this interval in linux-4.14.y:
2feb36e arm64: kpti: Add ->enable callback to remap swapper using nG mappings
ee28fed arm64: mm: Permit transitioning from Global to Non-Global without BBM
6928820 arm64: kpti: Make use of nG dependent on arm64_kernel_unmapped_at_el0()
c98c8c2 arm64: Turn on KPTI only on CPUs that need it
c98c8c2 is good, 2feb36e is bad - couldn't bisect in between, since it didn't
boot there.
And yes, when i tested 2feb36e i applied the "el1 trashing fix" mentioned here:
https://www.spinics.net/lists/arm-kernel/msg636489.html
Anything else i can do to help debug this?
--
bye,
p.
next reply other threads:[~2018-02-28 15:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 15:45 Paolo Pisati [this message]
2018-02-28 15:51 ` Internal error: Oops - BUG() / kvm boot race - arm64 kpti patchset related Ard Biesheuvel
2018-02-28 16:13 ` Paolo Pisati
2018-02-28 15:51 ` Marc Zyngier
2018-02-28 16:15 ` Paolo Pisati
2018-02-28 16:07 ` Will Deacon
2018-02-28 16:12 ` Paolo Pisati
2018-02-28 16:18 ` Will Deacon
2018-02-28 16:25 ` Paolo Pisati
2018-02-28 16:18 ` Mark Rutland
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