diff mbox series

[01/17] hw/misc/ivshmem: Fix missing ERRP_GUARD() for error_prepend()

Message ID 20240229143914.1977550-2-zhao1.liu@linux.intel.com
State New
Headers show
Series Cleanup up to fix missing ERRP_GUARD() for error_prepend() | expand

Commit Message

Zhao Liu Feb. 29, 2024, 2:38 p.m. UTC 
From: Zhao Liu <zhao1.liu@intel.com>

As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
*   error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.

ERRP_GUARD() could avoid the case when @errp is the pointer of
error_fatal, the user can't see this additional information, because
exit() happens in error_setg earlier than information is added [1].

The ivshmem_common_realize() passes @errp to error_prepend(), and as a
DeviceClass.realize method, its @errp is so widely sourced that it is
necessary to protect it with ERRP_GUARD().

To avoid the issue like [1] said, add missing ERRP_GUARD() at the
beginning of this function.

[1]: Issue description in the commit message of commit ae7c80a7bd73
     ("error: New macro ERRP_GUARD()").

Cc: Juan Quintela <quintela@trasno.org>
Cc: Steve Sistare <steven.sistare@oracle.com>
Cc: "Philippe Mathieu-Daudé" <philmd@linaro.org>
Cc: Michael Galaxy <mgalaxy@akamai.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 hw/misc/ivshmem.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Thomas Huth Feb. 29, 2024, 5:23 p.m. UTC | #1 
On 29/02/2024 15.38, Zhao Liu wrote:
> From: Zhao Liu <zhao1.liu@intel.com>
> 
> As the comment in qapi/error, passing @errp to error_prepend() requires
> ERRP_GUARD():
> 
> * = Why, when and how to use ERRP_GUARD() =
> *
> * Without ERRP_GUARD(), use of the @errp parameter is restricted:
> ...
> * - It should not be passed to error_prepend(), error_vprepend() or
> *   error_append_hint(), because that doesn't work with &error_fatal.
> * ERRP_GUARD() lifts these restrictions.
> *
> * To use ERRP_GUARD(), add it right at the beginning of the function.
> * @errp can then be used without worrying about the argument being
> * NULL or &error_fatal.
> 
> ERRP_GUARD() could avoid the case when @errp is the pointer of
> error_fatal, the user can't see this additional information, because
> exit() happens in error_setg earlier than information is added [1].
> 
> The ivshmem_common_realize() passes @errp to error_prepend(), and as a
> DeviceClass.realize method, its @errp is so widely sourced that it is
> necessary to protect it with ERRP_GUARD().
> 
> To avoid the issue like [1] said, add missing ERRP_GUARD() at the
> beginning of this function.
> 
> [1]: Issue description in the commit message of commit ae7c80a7bd73
>       ("error: New macro ERRP_GUARD()").
> 
> Cc: Juan Quintela <quintela@trasno.org>
> Cc: Steve Sistare <steven.sistare@oracle.com>
> Cc: "Philippe Mathieu-Daudé" <philmd@linaro.org>
> Cc: Michael Galaxy <mgalaxy@akamai.com>
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>   hw/misc/ivshmem.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index a2fd0bc36544..de49d1b8a826 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -832,6 +832,7 @@ static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
>   
>   static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
>   {
> +    ERRP_GUARD();
>       IVShmemState *s = IVSHMEM_COMMON(dev);
>       Error *err = NULL;

Please remove "err" and the error_propagate in here now.

  Thomas
Zhao Liu March 1, 2024, 6:41 a.m. UTC | #2 
> > @@ -832,6 +832,7 @@ static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
> >   static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
> >   {
> > +    ERRP_GUARD();
> >       IVShmemState *s = IVSHMEM_COMMON(dev);
> >       Error *err = NULL;
> 
> Please remove "err" and the error_propagate in here now.

OK, I hadn't thought of that. Thanks.

Regards,
Zhao
diff mbox series

Patch

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index a2fd0bc36544..de49d1b8a826 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -832,6 +832,7 @@  static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
 
 static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
 {
+    ERRP_GUARD();
     IVShmemState *s = IVSHMEM_COMMON(dev);
     Error *err = NULL;
     uint8_t *pci_conf;