drm/xe: Fix ref counting leak on page fault

If a page fault occurs on VM not in fault a ref can be leaked. Fix this.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240301041036.238471-1-matthew.brost@intel.com
(cherry picked from commit 27b5a3f237fe66dbf2288c2b50973aee8a427e41)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
index c26e4fc..73c5351 100644 (file)
--- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
@@ -146,10 +146,12 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf)
        /* ASID to VM */
        mutex_lock(&xe->usm.lock);
        vm = xa_load(&xe->usm.asid_to_vm, pf->asid);
-       if (vm)
+       if (vm && xe_vm_in_fault_mode(vm))
                xe_vm_get(vm);
+       else
+               vm = NULL;
        mutex_unlock(&xe->usm.lock);
-       if (!vm || !xe_vm_in_fault_mode(vm))
+       if (!vm)
                return -EINVAL;
 
 retry_userptr: