[libvirt] [PATCH 2/2] qemu: Add and use qemuProcessEventFree for freeing qemuProcessEvents

Michal Privoznik mprivozn at redhat.com
Mon Feb 5 09:35:31 UTC 2018


On 02/02/2018 01:13 PM, Marc Hartmayer wrote:
> Add and use qemuProcessEventFree for freeing qemuProcessEvents. This
> is less error-prone as the compiler can help us make sure that for
> every new enumeration value of qemuProcessEventType the
> qemuProcessEventFree function has to be adapted.
> 
> All process*Event functions are *only* called by
> qemuProcessHandleEvent and this function does the freeing by itself
> with qemuProcessEventFree. This means that an explicit freeing of
> processEvent->data is no longer required in each process*Event
> handler.
> 
> The effectiveness of this change is also demonstrated by the fact that
> it fixes a memory leak of the panic info data in
> qemuProcessHandleGuestPanic.
> 
> Reported-by: Wang Dong <dongdwdw at linux.vnet.ibm.com>
> Signed-off-by: Bjoern Walk <bwalk at linux.vnet.ibm.com>
> Signed-off-by: Marc Hartmayer <mhartmay at linux.vnet.ibm.com>
> Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
> ---
>  src/qemu/qemu_domain.c  | 23 +++++++++++++++++++++++
>  src/qemu/qemu_domain.h  |  2 ++
>  src/qemu/qemu_driver.c  | 12 ++----------
>  src/qemu/qemu_process.c | 22 +++++++---------------
>  4 files changed, 34 insertions(+), 25 deletions(-)
> 
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index c8123ce59bc4..4472b00d6540 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -10910,3 +10910,26 @@ qemuDomainPrepareDiskSource(virConnectPtr conn,
>  
>      return 0;
>  }
> +
> +
> +void
> +qemuProcessEventFree(struct qemuProcessEvent *event)
> +{
> +    if (!event)
> +        return;
> +
> +    switch (event->eventType) {
> +    case QEMU_PROCESS_EVENT_GUESTPANIC:
> +        qemuMonitorEventPanicInfoFree(event->data);
> +        break;
> +    case QEMU_PROCESS_EVENT_WATCHDOG:
> +    case QEMU_PROCESS_EVENT_DEVICE_DELETED:
> +    case QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED:
> +    case QEMU_PROCESS_EVENT_SERIAL_CHANGED:
> +    case QEMU_PROCESS_EVENT_BLOCK_JOB:
> +    case QEMU_PROCESS_EVENT_MONITOR_EOF:
> +    case QEMU_PROCESS_EVENT_LAST:
> +        VIR_FREE(event->data);

We should take EVENT_LAST to a separate block.

> +    }
> +    VIR_FREE(event);
> +}
> diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
> index ddfc46dcd0c1..7c9364f0bb69 100644
> --- a/src/qemu/qemu_domain.h
> +++ b/src/qemu/qemu_domain.h
> @@ -445,6 +445,8 @@ struct qemuProcessEvent {
>      void *data;
>  };
>  
> +void qemuProcessEventFree(struct qemuProcessEvent *event);
> +
>  typedef struct _qemuDomainLogContext qemuDomainLogContext;
>  typedef qemuDomainLogContext *qemuDomainLogContextPtr;
>  
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d64686df4c5f..d760b77c81e7 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4183,7 +4183,6 @@ processWatchdogEvent(virQEMUDriverPtr driver,
>      qemuDomainObjEndAsyncJob(driver, vm);
>  
>   cleanup:
> -    VIR_FREE(dumpfile);
>      virObjectUnref(cfg);

No. @dumpfile is not taken from qemuProcessEvent rather than allocated
in this function. This VIR_FREE() needs to stay.

>  }
>  
> @@ -4309,7 +4308,6 @@ processGuestPanicEvent(virQEMUDriverPtr driver,
>          qemuDomainRemoveInactiveJob(driver, vm);
>  
>   cleanup:
> -    qemuMonitorEventPanicInfoFree(info);
>      virObjectUnref(cfg);
>  }
>  
> @@ -4351,7 +4349,6 @@ processDeviceDeletedEvent(virQEMUDriverPtr driver,
>      qemuDomainObjEndJob(driver, vm);
>  
>   cleanup:
> -    VIR_FREE(devAlias);

This one is correct though. BTW: Now we can mark all these @devAlias
arguments as 'const' to express it explicitly that we don't want these
functions to free it.

ACK with that changed.

As a second step - should we move all those virObjectUnref(vm) calls
into qemuProcessEventFree()? I mean those cases where
virThreadPoolSendJob() fails and we call virObjectUnref(vm) followed by
qemuProcessEventFree().

Michal




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