[v1] Cleanup up to fix missing ERRP_GUARD() for error_prepend()

[PATCH 02/16] backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

Zhao Liu posted 16 patches 9 months ago

Diff against v1 v2
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Maintainers: Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, John Snow <jsnow@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Eric Blake <eblake@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Stefan Weil <sw@weilnetz.de>, "Michael S. Tsirkin" <mst@redhat.com>, Stefano Stabellini <sstabellini@kernel.org>, Anthony Perard <anthony.perard@citrix.com>, Paul Durrant <paul@xen.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Paul Burton <paulburton@kernel.org>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Markus Armbruster <armbru@redhat.com>, Michael Roth <michael.roth@amd.com>

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[PATCH 02/16] backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

Posted by Zhao Liu 9 months ago

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 iommufd_backend_set_fd() passes @errp to error_prepend(), to avoid
the above issue, 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: Yi Liu <yi.l.liu@intel.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 backends/iommufd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/backends/iommufd.c b/backends/iommufd.c
index 1ef683c7b080..62a79fa6b049 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -43,6 +43,7 @@ static void iommufd_backend_finalize(Object *obj)
 
 static void iommufd_backend_set_fd(Object *obj, const char *str, Error **errp)
 {
+    ERRP_GUARD();
     IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
     int fd = -1;
 
-- 
2.34.1

RE: [PATCH 02/16] backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

Posted by Duan, Zhenzhong 9 months ago


>-----Original Message-----
>From: Zhao Liu <zhao1.liu@linux.intel.com>
>Subject: [PATCH 02/16] backends/iommufd: Fix missing ERRP_GUARD() for
>error_prepend()
>
>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 iommufd_backend_set_fd() passes @errp to error_prepend(), to avoid
>the above issue, 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: Yi Liu <yi.l.liu@intel.com>
>Cc: Eric Auger <eric.auger@redhat.com>
>Cc: Zhenzhong Duan <zhenzhong.duan@intel.com>
>Signed-off-by: Zhao Liu <zhao1.liu@intel.com>

Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

Thanks
Zhenzhong

>---
> backends/iommufd.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/backends/iommufd.c b/backends/iommufd.c
>index 1ef683c7b080..62a79fa6b049 100644
>--- a/backends/iommufd.c
>+++ b/backends/iommufd.c
>@@ -43,6 +43,7 @@ static void iommufd_backend_finalize(Object *obj)
>
> static void iommufd_backend_set_fd(Object *obj, const char *str, Error
>**errp)
> {
>+    ERRP_GUARD();
>     IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
>     int fd = -1;
>
>--
>2.34.1