| Message ID | 20211005122031.809857-1-qperret@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Release mmap_lock when using VM_SHARED with MTE | expand |
On Tue, 5 Oct 2021 13:20:31 +0100, Quentin Perret wrote: > VM_SHARED mappings are currently forbidden in a memslot with MTE to > prevent two VMs racing to sanitise the same page. However, this check > is performed while holding current->mm's mmap_lock, but fails to release > it. Fix this by releasing the lock when needed. Applied to fixes, thanks! [1/1] KVM: arm64: Release mmap_lock when using VM_SHARED with MTE commit: 6e6a8ef088e1222cb1250942f51ad9c1ab219ab2 Cheers, M.
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 1a94a7ca48f2..69bd1732a299 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1529,8 +1529,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, * when updating the PG_mte_tagged page flag, see * sanitise_mte_tags for more details. */ - if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) - return -EINVAL; + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) { + ret = -EINVAL; + break; + } if (vma->vm_flags & VM_PFNMAP) { /* IO region dirty page logging not allowed */
VM_SHARED mappings are currently forbidden in a memslot with MTE to prevent two VMs racing to sanitise the same page. However, this check is performed while holding current->mm's mmap_lock, but fails to release it. Fix this by releasing the lock when needed. Fixes: ea7fc1bb1cd1 ("KVM: arm64: Introduce MTE VM feature") Signed-off-by: Quentin Perret <qperret@google.com> --- arch/arm64/kvm/mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)