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[v2,11/29] block/vdi: Fix missing ERRP_GUARD() for error_prepend()

Message ID 20240311033822.3142585-12-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 March 11, 2024, 3:38 a.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 &error_fatal, the user
can't see this additional information, because exit() happens in
error_setg earlier than information is added [1].

The vdi_co_do_create() passes @errp to error_prepend() without
ERRP_GUARD(), and its @errp parameter is so widely sourced that it is
necessary to protect it with ERRP_GUARD().

To avoid the potential issues as [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: Stefan Weil <sw@weilnetz.de>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 block/vdi.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Thomas Huth March 12, 2024, 8:14 a.m. UTC | #1 
On 11/03/2024 04.38, 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 &error_fatal, the user
> can't see this additional information, because exit() happens in
> error_setg earlier than information is added [1].
> 
> The vdi_co_do_create() passes @errp to error_prepend() without
> ERRP_GUARD(), and its @errp parameter is so widely sourced that it is
> necessary to protect it with ERRP_GUARD().
> 
> To avoid the potential issues as [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: Stefan Weil <sw@weilnetz.de>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: Hanna Reitz <hreitz@redhat.com>
> Cc: qemu-block@nongnu.org
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>   block/vdi.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/block/vdi.c b/block/vdi.c
> index 3b57becb9fe0..6363da08cee9 100644
> --- a/block/vdi.c
> +++ b/block/vdi.c
> @@ -738,6 +738,7 @@ static int coroutine_fn GRAPH_UNLOCKED
>   vdi_co_do_create(BlockdevCreateOptions *create_options, size_t block_size,
>                    Error **errp)
>   {
> +    ERRP_GUARD();
>       BlockdevCreateOptionsVdi *vdi_opts;
>       int ret = 0;
>       uint64_t bytes = 0;

Reviewed-by: Thomas Huth <thuth@redhat.com>
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Patch

diff --git a/block/vdi.c b/block/vdi.c
index 3b57becb9fe0..6363da08cee9 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -738,6 +738,7 @@  static int coroutine_fn GRAPH_UNLOCKED
 vdi_co_do_create(BlockdevCreateOptions *create_options, size_t block_size,
                  Error **errp)
 {
+    ERRP_GUARD();
     BlockdevCreateOptionsVdi *vdi_opts;
     int ret = 0;
     uint64_t bytes = 0;