From ecc34514032017857dcf514d8b7a83973f084e41 Mon Sep 17 00:00:00 2001

Message-Id: <ecc34514032017857dcf514d8b7a83973f084e41.1380112457.git.jdenemar@redhat.com>

From: Eric Blake <eblake@redhat.com>

Date: Mon, 23 Sep 2013 11:10:06 -0600

Subject: [PATCH] qemu: don't leak vm on failure

https://bugzilla.redhat.com/show_bug.cgi?id=1010617

Failure to attach to a domain during 'virsh qemu-attach' left

the list of domains in an odd state:

$ virsh qemu-attach 4176

error: An error occurred, but the cause is unknown

$ virsh list --all

 Id    Name                           State

----------------------------------------------------

 2     foo                            shut off

$ virsh qemu-attach 4176

error: Requested operation is not valid: domain is already active as 'foo'

$ virsh undefine foo

error: Failed to undefine domain foo

error: Requested operation is not valid: cannot undefine transient domain

$ virsh shutdown foo

error: Failed to shutdown domain foo

error: invalid argument: monitor must not be NULL

It all stems from leaving the list of domains unmodified on

the initial failure; we should follow the lead of createXML

which removes vm on failure (the actual initial failure still

needs to be fixed in a later patch, but at least this patch

gets us to the point where we aren't getting stuck with an

unremovable "shut off" transient domain).

While investigating, I also found a leak in qemuDomainCreateXML;

the two functions should behave similarly.  Note that there are

still two unusual paths: if dom is not allocated, the user will

see an OOM error even though the vm remains registered (but oom

errors already indicate tricky cleanup); and if the vm starts

and then quits again all before the job ends, it is possible

to return a non-NULL dom even though the dom will no longer be

useful for anything (but this at least lets the user know their

short-lived vm ran).

* src/qemu/qemu_driver.c (qemuDomainCreateXML): Don't leak vm on

failure to obtain job.

(qemuDomainQemuAttach): Match cleanup of qemuDomainCreateXML.

Signed-off-by: Eric Blake <eblake@redhat.com>

(cherry picked from commit d047b2d9835cbe5090e9eedb11ab69e7e4522f76)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_driver.c | 33 ++++++++++++++++++++-------------

 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index eb1a2ce..693dd85 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -1602,8 +1602,11 @@ static virDomainPtr qemuDomainCreateXML(virConnectPtr conn,

     def = NULL;

-    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)

-        goto cleanup; /* XXXX free the 'vm' we created ? */

+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) {

+        qemuDomainRemoveInactive(driver, vm);

+        vm = NULL;

+        goto cleanup;

+    }

     if (qemuProcessStart(conn, driver, vm, NULL, -1, NULL, NULL,

                          VIR_NETDEV_VPORT_PROFILE_OP_CREATE,

@@ -1631,10 +1634,10 @@ static virDomainPtr qemuDomainCreateXML(virConnectPtr conn,

     virDomainAuditStart(vm, "booted", true);

     dom = virGetDomain(conn, vm->def->name, vm->def->uuid);

-    if (dom) dom->id = vm->def->id;

+    if (dom)

+        dom->id = vm->def->id;

-    if (vm &&

-        qemuDomainObjEndJob(driver, vm) == 0)

+    if (qemuDomainObjEndJob(driver, vm) == 0)

         vm = NULL;

 cleanup:

@@ -13885,34 +13888,38 @@ static virDomainPtr qemuDomainQemuAttach(virConnectPtr conn,

     def = NULL;

-    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)

+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) {

+        qemuDomainRemoveInactive(driver, vm);

+        vm = NULL;

         goto cleanup;

+    }

     if (qemuProcessAttach(conn, driver, vm, pid,

                           pidfile, monConfig, monJSON) < 0) {

+        if (qemuDomainObjEndJob(driver, vm) > 0)

+            qemuDomainRemoveInactive(driver, vm);

+        vm = NULL;

         monConfig = NULL;

-        goto endjob;

+        goto cleanup;

     }

     monConfig = NULL;

     dom = virGetDomain(conn, vm->def->name, vm->def->uuid);

-    if (dom) dom->id = vm->def->id;

+    if (dom)

+        dom->id = vm->def->id;

-endjob:

-    if (qemuDomainObjEndJob(driver, vm) == 0) {

+    if (qemuDomainObjEndJob(driver, vm) == 0)

         vm = NULL;

-        goto cleanup;

-    }

 cleanup:

     virDomainDefFree(def);

-    virObjectUnref(qemuCaps);

     virDomainChrSourceDefFree(monConfig);

     if (vm)

         virObjectUnlock(vm);

     VIR_FREE(pidfile);

     virObjectUnref(caps);

+    virObjectUnref(qemuCaps);

     return dom;

 }

-- 

1.8.3.2