From: Quentin Perret <qperret@xxxxxxxxxx> [ Upstream commit 6e6a8ef088e1222cb1250942f51ad9c1ab219ab2 ] 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@xxxxxxxxxx> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> Link: https://lore.kernel.org/r/20211005122031.809857-1-qperret@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/arm64/kvm/mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 0625bf2353c2..3fcdacfee579 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1477,8 +1477,10 @@ 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 */ -- 2.33.0