FAILED: patch "[PATCH] KVM: arm64: Check for kvm_vma_mte_allowed in the critical" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 8c2e8ac8ad4be68409e806ce1cc78fc7a04539f3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023040350-shrouded-scribble-3c39@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

8c2e8ac8ad4b ("KVM: arm64: Check for kvm_vma_mte_allowed in the critical section")
13ec9308a857 ("KVM: arm64: Retry fault if vma_lookup() results become invalid")
b0803ba72b55 ("KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_*")
382b5b87a97d ("Merge branch kvm-arm64/mte-map-shared into kvmarm-master/next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8c2e8ac8ad4be68409e806ce1cc78fc7a04539f3 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 16 Mar 2023 17:45:46 +0000
Subject: [PATCH] KVM: arm64: Check for kvm_vma_mte_allowed in the critical
 section

On page fault, we find about the VMA that backs the page fault
early on, and quickly release the mmap_read_lock. However, using
the VMA pointer after the critical section is pretty dangerous,
as a teardown may happen in the meantime and the VMA be long gone.

Move the sampling of the MTE permission early, and NULL-ify the
VMA pointer after that, just to be on the safe side.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230316174546.3777507-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index cd819725193b..3b9d4d24c361 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1218,7 +1218,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 {
 	int ret = 0;
 	bool write_fault, writable, force_pte = false;
-	bool exec_fault;
+	bool exec_fault, mte_allowed;
 	bool device = false;
 	unsigned long mmu_seq;
 	struct kvm *kvm = vcpu->kvm;
@@ -1309,6 +1309,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		fault_ipa &= ~(vma_pagesize - 1);
 
 	gfn = fault_ipa >> PAGE_SHIFT;
+	mte_allowed = kvm_vma_mte_allowed(vma);
+
+	/* Don't use the VMA after the unlock -- it may have vanished */
+	vma = NULL;
 
 	/*
 	 * Read mmu_invalidate_seq so that KVM can detect if the results of
@@ -1379,7 +1383,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 
 	if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) {
 		/* Check the VMM hasn't introduced a new disallowed VMA */
-		if (kvm_vma_mte_allowed(vma)) {
+		if (mte_allowed) {
 			sanitise_mte_tags(kvm, pfn, vma_pagesize);
 		} else {
 			ret = -EFAULT;