Messages in this thread | | | Date | Mon, 24 Aug 2020 13:56:18 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH stable-4.14.y backport] KVM: arm/arm64: Don't reschedule in unmap_stage2_range() |
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On 2020-08-24 12:29, Will Deacon wrote: > Upstream commits fdfe7cbd5880 ("KVM: Pass MMU notifier range flags to > kvm_unmap_hva_range()") and b5331379bc62 ("KVM: arm64: Only reschedule > if MMU_NOTIFIER_RANGE_BLOCKABLE is not set") fix a "sleeping from > invalid > context" BUG caused by unmap_stage2_range() attempting to reschedule > when > called on the OOM path. > > Unfortunately, these patches rely on the MMU notifier callback being > passed knowledge about whether or not blocking is permitted, which was > introduced in 4.19. Rather than backport this considerable amount of > infrastructure just for KVM on arm, instead just remove the conditional > reschedule. > > Cc: <stable@vger.kernel.org> # v4.14 only > Cc: Marc Zyngier <maz@kernel.org> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: James Morse <james.morse@arm.com> > Signed-off-by: Will Deacon <will@kernel.org> > --- > virt/kvm/arm/mmu.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index 3814cdad643a..7fe673248e98 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -307,12 +307,6 @@ static void unmap_stage2_range(struct kvm *kvm, > phys_addr_t start, u64 size) > next = stage2_pgd_addr_end(addr, end); > if (!stage2_pgd_none(*pgd)) > unmap_stage2_puds(kvm, pgd, addr, next); > - /* > - * If the range is too large, release the kvm->mmu_lock > - * to prevent starvation and lockup detector warnings. > - */ > - if (next != end) > - cond_resched_lock(&kvm->mmu_lock); > } while (pgd++, addr = next, addr != end); > }
Acked-by: Marc Zyngier <maz@kernel.org>
M. -- Jazz is not dead. It just smells funny...
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