[Stable-9.2.2 07/14] vfio/iommufd: Fix SIGSEV in iommufd_cdev_attach()

[Michael Tokarev]

From: Zhenzhong Duan <zhenzhong.d...@intel.com>

When iommufd_cdev_ram_block_discard_disable() fails for whatever reason,
errp should be set or else SIGSEV is triggered in vfio_realize() when
error_prepend() is called.

By this chance, use the same error message for both legacy and iommufd
backend.

Fixes: 5ee3dc7af785 ("vfio/iommufd: Implement the iommufd backend")
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Link: https://lore.kernel.org/r/20250116102307.260849-1-zhenzhong.d...@intel.com
Signed-off-by: Cédric Le Goater <c...@redhat.com>
(cherry picked from commit 7b3d5b84cbd742356a1afc6b0fa489d0663f235d)
Signed-off-by: Michael Tokarev <m...@tls.msk.ru>

diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index e7bece4ea1..a60c899dc6 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -515,8 +515,8 @@ static bool iommufd_cdev_attach(const char *name, 
VFIODevice *vbasedev,
         } else {
             ret = iommufd_cdev_ram_block_discard_disable(true);
             if (ret) {
-                error_setg(errp,
-                              "Cannot set discarding of RAM broken (%d)", ret);
+                error_setg_errno(errp, -ret,
+                                 "Cannot set discarding of RAM broken");
                 goto err_discard_disable;
             }
             goto found_container;
@@ -544,6 +544,7 @@ static bool iommufd_cdev_attach(const char *name, 
VFIODevice *vbasedev,
 
     ret = iommufd_cdev_ram_block_discard_disable(true);
     if (ret) {
+        error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken");
         goto err_discard_disable;
     }
 
-- 
2.39.5