4.11-stable patches

added patches:
	kvm-arm-arm64-fix-race-in-resetting-stage2-pgd.patch

diff --git a/queue-4.11/kvm-arm-arm64-fix-race-in-resetting-stage2-pgd.patch b/queue-4.11/kvm-arm-arm64-fix-race-in-resetting-stage2-pgd.patch
new file mode 100644 (file)
index 0000000..25dbe0f
--- /dev/null
+++ b/queue-4.11/kvm-arm-arm64-fix-race-in-resetting-stage2-pgd.patch
@@ -0,0 +1,108 @@
+From 6c0d706b563af732adb094c5bf807437e8963e84 Mon Sep 17 00:00:00 2001
+From: Suzuki K Poulose <suzuki.poulose@arm.com>
+Date: Wed, 3 May 2017 15:17:51 +0100
+Subject: kvm: arm/arm64: Fix race in resetting stage2 PGD
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Suzuki K Poulose <suzuki.poulose@arm.com>
+
+commit 6c0d706b563af732adb094c5bf807437e8963e84 upstream.
+
+In kvm_free_stage2_pgd() we check the stage2 PGD before holding
+the lock and proceed to take the lock if it is valid. And we unmap
+the page tables, followed by releasing the lock. We reset the PGD
+only after dropping this lock, which could cause a race condition
+where another thread waiting on or even holding the lock, could
+potentially see that the PGD is still valid and proceed to perform
+a stage2 operation and later encounter a NULL PGD.
+
+[223090.242280] Unable to handle kernel NULL pointer dereference at
+virtual address 00000040
+[223090.262330] PC is at unmap_stage2_range+0x8c/0x428
+[223090.262332] LR is at kvm_unmap_hva_handler+0x2c/0x3c
+[223090.262531] Call trace:
+[223090.262533] [<ffff0000080adb78>] unmap_stage2_range+0x8c/0x428
+[223090.262535] [<ffff0000080adf40>] kvm_unmap_hva_handler+0x2c/0x3c
+[223090.262537] [<ffff0000080ace2c>] handle_hva_to_gpa+0xb0/0x104
+[223090.262539] [<ffff0000080af988>] kvm_unmap_hva+0x5c/0xbc
+[223090.262543] [<ffff0000080a2478>]
+kvm_mmu_notifier_invalidate_page+0x50/0x8c
+[223090.262547] [<ffff0000082274f8>]
+__mmu_notifier_invalidate_page+0x5c/0x84
+[223090.262551] [<ffff00000820b700>] try_to_unmap_one+0x1d0/0x4a0
+[223090.262553] [<ffff00000820c5c8>] rmap_walk+0x1cc/0x2e0
+[223090.262555] [<ffff00000820c90c>] try_to_unmap+0x74/0xa4
+[223090.262557] [<ffff000008230ce4>] migrate_pages+0x31c/0x5ac
+[223090.262561] [<ffff0000081f869c>] compact_zone+0x3fc/0x7ac
+[223090.262563] [<ffff0000081f8ae0>] compact_zone_order+0x94/0xb0
+[223090.262564] [<ffff0000081f91c0>] try_to_compact_pages+0x108/0x290
+[223090.262569] [<ffff0000081d5108>] __alloc_pages_direct_compact+0x70/0x1ac
+[223090.262571] [<ffff0000081d64a0>] __alloc_pages_nodemask+0x434/0x9f4
+[223090.262572] [<ffff0000082256f0>] alloc_pages_vma+0x230/0x254
+[223090.262574] [<ffff000008235e5c>] do_huge_pmd_anonymous_page+0x114/0x538
+[223090.262576] [<ffff000008201bec>] handle_mm_fault+0xd40/0x17a4
+[223090.262577] [<ffff0000081fb324>] __get_user_pages+0x12c/0x36c
+[223090.262578] [<ffff0000081fb804>] get_user_pages_unlocked+0xa4/0x1b8
+[223090.262579] [<ffff0000080a3ce8>] __gfn_to_pfn_memslot+0x280/0x31c
+[223090.262580] [<ffff0000080a3dd0>] gfn_to_pfn_prot+0x4c/0x5c
+[223090.262582] [<ffff0000080af3f8>] kvm_handle_guest_abort+0x240/0x774
+[223090.262584] [<ffff0000080b2bac>] handle_exit+0x11c/0x1ac
+[223090.262586] [<ffff0000080ab99c>] kvm_arch_vcpu_ioctl_run+0x31c/0x648
+[223090.262587] [<ffff0000080a1d78>] kvm_vcpu_ioctl+0x378/0x768
+[223090.262590] [<ffff00000825df5c>] do_vfs_ioctl+0x324/0x5a4
+[223090.262591] [<ffff00000825e26c>] SyS_ioctl+0x90/0xa4
+[223090.262595] [<ffff000008085d84>] el0_svc_naked+0x38/0x3c
+
+This patch moves the stage2 PGD manipulation under the lock.
+
+Reported-by: Alexander Graf <agraf@suse.de>
+Cc: Mark Rutland <mark.rutland@arm.com>
+Cc: Marc Zyngier <marc.zyngier@arm.com>
+Cc: Paolo Bonzini <pbonzini@redhat.com>
+Cc: Radim Krčmář <rkrcmar@redhat.com>
+Reviewed-by: Christoffer Dall <cdall@linaro.org>
+Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
+Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
+Signed-off-by: Christoffer Dall <cdall@linaro.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ arch/arm/kvm/mmu.c |   16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+--- a/arch/arm/kvm/mmu.c
++++ b/arch/arm/kvm/mmu.c
+@@ -829,22 +829,22 @@ void stage2_unmap_vm(struct kvm *kvm)
+  * Walks the level-1 page table pointed to by kvm->arch.pgd and frees all
+  * underlying level-2 and level-3 tables before freeing the actual level-1 table
+  * and setting the struct pointer to NULL.
+- *
+- * Note we don't need locking here as this is only called when the VM is
+- * destroyed, which can only be done once.
+  */
+ void kvm_free_stage2_pgd(struct kvm *kvm)
+ {
+-      if (kvm->arch.pgd == NULL)
+-              return;
++      void *pgd = NULL;
+ 
+       spin_lock(&kvm->mmu_lock);
+-      unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
++      if (kvm->arch.pgd) {
++              unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
++              pgd = kvm->arch.pgd;
++              kvm->arch.pgd = NULL;
++      }
+       spin_unlock(&kvm->mmu_lock);
+ 
+       /* Free the HW pgd, one page at a time */
+-      free_pages_exact(kvm->arch.pgd, S2_PGD_SIZE);
+-      kvm->arch.pgd = NULL;
++      if (pgd)
++              free_pages_exact(pgd, S2_PGD_SIZE);
+ }
+ 
+ static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,

diff --git a/queue-4.11/series b/queue-4.11/series
index 7b12e4be00beaae5b06a519ab8fd06c9ae6ceb90..784ec67d02f29609f8764e2bca14494dfd0d0745 100644 (file)
--- a/queue-4.11/series
+++ b/queue-4.11/series
@@ -163,3 +163,4 @@ uwb-fix-device-quirk-on-big-endian-hosts.patch
 genirq-fix-chained-interrupt-data-ordering.patch
 nvme-unmap-cmb-and-remove-sysfs-file-in-reset-path.patch
 mips-loongson-3-select-mips_l1_cache_shift_6.patch
+kvm-arm-arm64-fix-race-in-resetting-stage2-pgd.patch