Re: [PATCH 06/17] hw/vfio/container: Fix missing ERRP_GUARD() for error_prepend()

2024-02-29 Thread Cédric Le Goater

Hello,

On 2/29/24 15:39, Zhao Liu wrote:

From: Zhao Liu 

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 _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 _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 vfio_get_group() passes @errp to error_prepend(). Its @errp is
from vfio_attach_device(), which @errp parameter 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: Alex Williamson 
Cc: "Cédric Le Goater" 
Signed-off-by: Zhao Liu 



Reviewed-by: Cédric Le Goater 

Thanks,

C.




Re: [PATCH 06/17] hw/vfio/container: Fix missing ERRP_GUARD() for error_prepend()

2024-02-29 Thread Thomas Huth

On 29/02/2024 15.39, Zhao Liu wrote:

From: Zhao Liu 

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 _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 _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 vfio_get_group() passes @errp to error_prepend(). Its @errp is
from vfio_attach_device(), which @errp parameter 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: Alex Williamson 
Cc: "Cédric Le Goater" 
Signed-off-by: Zhao Liu 
---
  hw/vfio/container.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index bd25b9fbad2e..f66bb01f5b18 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -719,6 +719,7 @@ static void vfio_disconnect_container(VFIOGroup *group)
  
  static VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp)

  {
+ERRP_GUARD();
  VFIOGroup *group;
  char path[32];
  struct vfio_group_status status = { .argsz = sizeof(status) };


Reviewed-by: Thomas Huth 




[PATCH 06/17] hw/vfio/container: Fix missing ERRP_GUARD() for error_prepend()

2024-02-29 Thread Zhao Liu
From: Zhao Liu 

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 _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 _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 vfio_get_group() passes @errp to error_prepend(). Its @errp is
from vfio_attach_device(), which @errp parameter 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: Alex Williamson 
Cc: "Cédric Le Goater" 
Signed-off-by: Zhao Liu 
---
 hw/vfio/container.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index bd25b9fbad2e..f66bb01f5b18 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -719,6 +719,7 @@ static void vfio_disconnect_container(VFIOGroup *group)
 
 static VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp)
 {
+ERRP_GUARD();
 VFIOGroup *group;
 char path[32];
 struct vfio_group_status status = { .argsz = sizeof(status) };
-- 
2.34.1