On 11/08/20 12:27, Will Deacon wrote: > Hi all, > > While stress-testing my arm64 stage-2 page-table rewrite [1], I ran into > a sleeping while atomic BUG() during OOM that I can reproduce with > mainline. > > The problem is that the arm64 page-table code periodically calls > cond_resched_lock() when unmapping the stage-2 page-tables, but in the > case of OOM, this occurs in atomic context. > > These couple of patches (based on 5.8) propagate the flags from the MMU > notifier range structure, which in turn indicate whether or not blocking > is permitted. > > Cheers, > > Will > > [1] https://android-kvm.googlesource.com/linux/+/refs/heads/topic/pgtable > > Cc: Marc Zyngier <maz@xxxxxxxxxx> > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > Cc: James Morse <james.morse@xxxxxxx> > Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> > Cc: Paul Mackerras <paulus@xxxxxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > --->8 > > Will Deacon (2): > KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() > KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set > > arch/arm64/include/asm/kvm_host.h | 2 +- > arch/arm64/kvm/mmu.c | 19 ++++++++++++++----- > arch/mips/include/asm/kvm_host.h | 2 +- > arch/mips/kvm/mmu.c | 3 ++- > arch/powerpc/include/asm/kvm_host.h | 3 ++- > arch/powerpc/kvm/book3s.c | 3 ++- > arch/powerpc/kvm/e500_mmu_host.c | 3 ++- > arch/x86/include/asm/kvm_host.h | 3 ++- > arch/x86/kvm/mmu/mmu.c | 3 ++- > virt/kvm/kvm_main.c | 3 ++- > 10 files changed, 30 insertions(+), 14 deletions(-) > These would be okay for 5.9 too, so I plan to queue them myself before we fork for 5.10. Paolo
