If __kvm_gmem_get_pfn() detects an hwpoisoned page, it returns -EHWPOISON but it does not put back the reference that kvm_gmem_get_folio() had grabbed. Add the forgotten folio_put().

Fixes: a7800aa80ea4 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- Sent v1 from the wrong directory, sorry about that.

virt/kvm/guest_memfd.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 3bfe1824ec2d..19c220ec1efd 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -549,7 +549,6 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, struct kvm_gmem *gmem = file->private_data; struct folio *folio; struct page *page; - int r;

if (file != slot->gmem.file) { WARN_ON_ONCE(slot->gmem.file); @@ -567,8 +566,9 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, return PTR_ERR(folio);

if (folio_test_hwpoison(folio)) { - r = -EHWPOISON; - goto out_unlock; + folio_unlock(folio); + folio_put(folio); + return -EHWPOISON; }

page = folio_file_page(folio, index); @@ -577,12 +577,8 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, if (max_order) *max_order = 0;

- r = 0; - -out_unlock: folio_unlock(folio); - - return r; + return 0; }

int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,