[libvirt] [PATCH 1/2] qemu: Fix incorrect jump labels in error paths

Marc Hartmayer posted 2 patches 8 years, 11 months ago
[libvirt] [PATCH 1/2] qemu: Fix incorrect jump labels in error paths
Posted by Marc Hartmayer 8 years, 11 months ago
Fix incorrect jump labels in error paths as the stop jump is only
needed if the driver has already changed the state. For example
'virAtomicIntInc(&driver->nactive)' will be 'reverted' in the
qemuProcessStop call.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
---
 src/qemu/qemu_process.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index ea10fff..a57d136 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4755,9 +4755,12 @@ qemuProcessInit(virQEMUDriverPtr driver,
      */
     VIR_DEBUG("Setting current domain def as transient");
     if (virDomainObjSetDefTransient(caps, driver->xmlopt, vm) < 0)
-        goto stop;
+        goto cleanup;
 
-    if (!(flags & VIR_QEMU_PROCESS_START_PRETEND)) {
+    if (flags & VIR_QEMU_PROCESS_START_PRETEND) {
+        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
+            goto cleanup;
+    } else {
         vm->def->id = qemuDriverAllocateID(driver);
         qemuDomainSetFakeReboot(driver, vm, false);
         virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_STARTING_UP);
@@ -4770,10 +4773,10 @@ qemuProcessInit(virQEMUDriverPtr driver,
                                  VIR_HOOK_QEMU_OP_PREPARE,
                                  VIR_HOOK_SUBOP_BEGIN) < 0)
             goto stop;
-    }
 
-    if (qemuDomainSetPrivatePaths(driver, vm) < 0)
-        goto cleanup;
+        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
+            goto stop;
+    }
 
     ret = 0;
 
-- 
2.5.5

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Re: [libvirt] [PATCH 1/2] qemu: Fix incorrect jump labels in error paths
Posted by Michal Privoznik 8 years, 11 months ago
On 02/23/2017 10:44 AM, Marc Hartmayer wrote:
> Fix incorrect jump labels in error paths as the stop jump is only
> needed if the driver has already changed the state. For example
> 'virAtomicIntInc(&driver->nactive)' will be 'reverted' in the
> qemuProcessStop call.
> 
> Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
> Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
> ---
>  src/qemu/qemu_process.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index ea10fff..a57d136 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -4755,9 +4755,12 @@ qemuProcessInit(virQEMUDriverPtr driver,
>       */
>      VIR_DEBUG("Setting current domain def as transient");
>      if (virDomainObjSetDefTransient(caps, driver->xmlopt, vm) < 0)
> -        goto stop;
> +        goto cleanup;
>  
> -    if (!(flags & VIR_QEMU_PROCESS_START_PRETEND)) {
> +    if (flags & VIR_QEMU_PROCESS_START_PRETEND) {
> +        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
> +            goto cleanup;

This should have been goto stop; After SetDefTransien() succeeds,
everything must goto stop in order to call qemuProcessStop which undoes
the SetDefTransient(). I will fix it before pushing.

> +    } else {
>          vm->def->id = qemuDriverAllocateID(driver);
>          qemuDomainSetFakeReboot(driver, vm, false);
>          virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_STARTING_UP);
> @@ -4770,10 +4773,10 @@ qemuProcessInit(virQEMUDriverPtr driver,
>                                   VIR_HOOK_QEMU_OP_PREPARE,
>                                   VIR_HOOK_SUBOP_BEGIN) < 0)
>              goto stop;
> -    }
>  
> -    if (qemuDomainSetPrivatePaths(driver, vm) < 0)
> -        goto cleanup;
> +        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
> +            goto stop;
> +    }
>  
>      ret = 0;
>  
> 

ACKed and pushed.

Michal

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Re: [libvirt] [PATCH 1/2] qemu: Fix incorrect jump labels in error paths
Posted by Marc Hartmayer 8 years, 11 months ago
On Thu, Feb 23, 2017 at 03:33 PM +0100, Michal Privoznik <mprivozn@redhat.com> wrote:
> On 02/23/2017 10:44 AM, Marc Hartmayer wrote:
>> Fix incorrect jump labels in error paths as the stop jump is only
>> needed if the driver has already changed the state. For example
>> 'virAtomicIntInc(&driver->nactive)' will be 'reverted' in the
>> qemuProcessStop call.
>>
>> Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
>> Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
>> ---
>>  src/qemu/qemu_process.c | 13 ++++++++-----
>>  1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
>> index ea10fff..a57d136 100644
>> --- a/src/qemu/qemu_process.c
>> +++ b/src/qemu/qemu_process.c
>> @@ -4755,9 +4755,12 @@ qemuProcessInit(virQEMUDriverPtr driver,
>>       */
>>      VIR_DEBUG("Setting current domain def as transient");
>>      if (virDomainObjSetDefTransient(caps, driver->xmlopt, vm) < 0)
>> -        goto stop;
>> +        goto cleanup;
>>
>> -    if (!(flags & VIR_QEMU_PROCESS_START_PRETEND)) {
>> +    if (flags & VIR_QEMU_PROCESS_START_PRETEND) {
>> +        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
>> +            goto cleanup;
>
> This should have been goto stop; After SetDefTransien() succeeds,
> everything must goto stop in order to call qemuProcessStop which undoes
> the SetDefTransient(). I will fix it before pushing.

Hmm why? In qemuProcessStop() the driver->nactive will be decreased and
I think that is definitely not what we want if we haven't increased
that value... (for the VIR_QEMU_PROCESS_START_PRETEND path)

>
>> +    } else {
>>          vm->def->id = qemuDriverAllocateID(driver);
>>          qemuDomainSetFakeReboot(driver, vm, false);
>>          virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_STARTING_UP);
>> @@ -4770,10 +4773,10 @@ qemuProcessInit(virQEMUDriverPtr driver,
>>                                   VIR_HOOK_QEMU_OP_PREPARE,
>>                                   VIR_HOOK_SUBOP_BEGIN) < 0)
>>              goto stop;
>> -    }
>>
>> -    if (qemuDomainSetPrivatePaths(driver, vm) < 0)
>> -        goto cleanup;
>> +        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
>> +            goto stop;
>> +    }
>>
>>      ret = 0;
>>
>>
>
> ACKed and pushed.
>
> Michal
>
--
Beste Grüße / Kind regards
   Marc Hartmayer

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Re: [libvirt] [PATCH 1/2] qemu: Fix incorrect jump labels in error paths
Posted by Michal Privoznik 8 years, 11 months ago
On 02/23/2017 04:57 PM, Marc Hartmayer wrote:
> On Thu, Feb 23, 2017 at 03:33 PM +0100, Michal Privoznik <mprivozn@redhat.com> wrote:
>> On 02/23/2017 10:44 AM, Marc Hartmayer wrote:
>>> Fix incorrect jump labels in error paths as the stop jump is only
>>> needed if the driver has already changed the state. For example
>>> 'virAtomicIntInc(&driver->nactive)' will be 'reverted' in the
>>> qemuProcessStop call.
>>>
>>> Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
>>> Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
>>> ---
>>>  src/qemu/qemu_process.c | 13 ++++++++-----
>>>  1 file changed, 8 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
>>> index ea10fff..a57d136 100644
>>> --- a/src/qemu/qemu_process.c
>>> +++ b/src/qemu/qemu_process.c
>>> @@ -4755,9 +4755,12 @@ qemuProcessInit(virQEMUDriverPtr driver,
>>>       */
>>>      VIR_DEBUG("Setting current domain def as transient");
>>>      if (virDomainObjSetDefTransient(caps, driver->xmlopt, vm) < 0)
>>> -        goto stop;
>>> +        goto cleanup;
>>>
>>> -    if (!(flags & VIR_QEMU_PROCESS_START_PRETEND)) {
>>> +    if (flags & VIR_QEMU_PROCESS_START_PRETEND) {
>>> +        if (qemuDomainSetPrivatePaths(driver, vm) < 0)
>>> +            goto cleanup;
>>
>> This should have been goto stop; After SetDefTransien() succeeds,
>> everything must goto stop in order to call qemuProcessStop which undoes
>> the SetDefTransient(). I will fix it before pushing.
> 
> Hmm why? In qemuProcessStop() the driver->nactive will be decreased and
> I think that is definitely not what we want if we haven't increased
> that value... (for the VIR_QEMU_PROCESS_START_PRETEND path)

Ah, that's a good point. On the other hand, we need to call
virDomainObjRemoveTransientDef(). So I guess the proper solution is to:

if (qemuDomainSetPrivatePaths(driver, vm) < 0) {
  virDomainObjRemoveTransientDef(vm);
  goto cleanup;
}

I'll post the patch shortly.

Michal

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