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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-25 09:32:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-25 09:32:10 -0800
commit6e20630e300486045bf480139c9e17e7071629ce (patch)
tree18cf7a38b27e484f1ff65948afb7545977f33fc0
parent525273fb2e7c84c98e3dffc5b446141bda99ff01 (diff)
parentbda646dd182a90ba4239fc62b71eb8b73126fa77 (diff)
downloadlinux-6e20630e300486045bf480139c9e17e7071629ce.tar.bz2
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Radim Krčmář: "Fix races and a potential use after free in the s390 cmma migration code" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: s390: add proper locking for CMMA migration bitmap
-rw-r--r--arch/s390/kvm/kvm-s390.c18
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2598cf243b86..1371dff2b90d 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -769,7 +769,7 @@ static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req)
/*
* Must be called with kvm->srcu held to avoid races on memslots, and with
- * kvm->lock to avoid races with ourselves and kvm_s390_vm_stop_migration.
+ * kvm->slots_lock to avoid races with ourselves and kvm_s390_vm_stop_migration.
*/
static int kvm_s390_vm_start_migration(struct kvm *kvm)
{
@@ -825,7 +825,7 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm)
}
/*
- * Must be called with kvm->lock to avoid races with ourselves and
+ * Must be called with kvm->slots_lock to avoid races with ourselves and
* kvm_s390_vm_start_migration.
*/
static int kvm_s390_vm_stop_migration(struct kvm *kvm)
@@ -840,6 +840,8 @@ static int kvm_s390_vm_stop_migration(struct kvm *kvm)
if (kvm->arch.use_cmma) {
kvm_s390_sync_request_broadcast(kvm, KVM_REQ_STOP_MIGRATION);
+ /* We have to wait for the essa emulation to finish */
+ synchronize_srcu(&kvm->srcu);
vfree(mgs->pgste_bitmap);
}
kfree(mgs);
@@ -849,14 +851,12 @@ static int kvm_s390_vm_stop_migration(struct kvm *kvm)
static int kvm_s390_vm_set_migration(struct kvm *kvm,
struct kvm_device_attr *attr)
{
- int idx, res = -ENXIO;
+ int res = -ENXIO;
- mutex_lock(&kvm->lock);
+ mutex_lock(&kvm->slots_lock);
switch (attr->attr) {
case KVM_S390_VM_MIGRATION_START:
- idx = srcu_read_lock(&kvm->srcu);
res = kvm_s390_vm_start_migration(kvm);
- srcu_read_unlock(&kvm->srcu, idx);
break;
case KVM_S390_VM_MIGRATION_STOP:
res = kvm_s390_vm_stop_migration(kvm);
@@ -864,7 +864,7 @@ static int kvm_s390_vm_set_migration(struct kvm *kvm,
default:
break;
}
- mutex_unlock(&kvm->lock);
+ mutex_unlock(&kvm->slots_lock);
return res;
}
@@ -1754,7 +1754,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = -EFAULT;
if (copy_from_user(&args, argp, sizeof(args)))
break;
+ mutex_lock(&kvm->slots_lock);
r = kvm_s390_get_cmma_bits(kvm, &args);
+ mutex_unlock(&kvm->slots_lock);
if (!r) {
r = copy_to_user(argp, &args, sizeof(args));
if (r)
@@ -1768,7 +1770,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = -EFAULT;
if (copy_from_user(&args, argp, sizeof(args)))
break;
+ mutex_lock(&kvm->slots_lock);
r = kvm_s390_set_cmma_bits(kvm, &args);
+ mutex_unlock(&kvm->slots_lock);
break;
}
default: