i386: Never free migration blocker objects instead of sometimes

invtsc_mig_blocker has static storage duration.  When a CPU with
certain features is initialized, and invtsc_mig_blocker is still null,
we add a migration blocker and store it in invtsc_mig_blocker.

The object is freed when migrate_add_blocker() fails, leaving
invtsc_mig_blocker dangling.  It is not freed on later failures.

Same for hv_passthrough_mig_blocker and hv_no_nonarch_cs_mig_blocker.

All failures are actually fatal, so whether we free or not doesn't
really matter, except as bad examples to be copied / imitated.

Clean this up in a minimal way: never free these blocker objects.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210720125408.387910-7-armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index e69abe48e3f887b29ef0d4f8e52a4717d238cc38..57aed525b557e8eb0ecb4d51836b28b65947ebec 100644 (file)
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1437,7 +1437,6 @@ static int hyperv_init_vcpu(X86CPU *cpu)
         ret = migrate_add_blocker(hv_passthrough_mig_blocker, &local_err);
         if (local_err) {
             error_report_err(local_err);
-            error_free(hv_passthrough_mig_blocker);
             return ret;
         }
     }
@@ -1452,7 +1451,6 @@ static int hyperv_init_vcpu(X86CPU *cpu)
         ret = migrate_add_blocker(hv_no_nonarch_cs_mig_blocker, &local_err);
         if (local_err) {
             error_report_err(local_err);
-            error_free(hv_no_nonarch_cs_mig_blocker);
             return ret;
         }
     }
@@ -1892,7 +1890,6 @@ int kvm_arch_init_vcpu(CPUState *cs)
             r = migrate_add_blocker(invtsc_mig_blocker, &local_err);
             if (local_err) {
                 error_report_err(local_err);
-                error_free(invtsc_mig_blocker);
                 return r;
             }
         }