[PATCH][next] KVM: x86: Fix potential fput on a null source_kvm_file

From: Colin King
Date: Fri Apr 30 2021 - 13:03:30 EST

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The fget can potentially return null, so the fput on the error return
path can cause a null pointer dereference. Fix this by checking for
a null source_kvm_file before doing a fput.

Addresses-Coverity: ("Dereference null return")
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
arch/x86/kvm/svm/sev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1356ee095cd5..8b11c711a0e4 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1764,7 +1764,8 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd)
- fput(source_kvm_file);
+ if (source_kvm_file)
+ fput(source_kvm_file);
return ret;