We switched to use refcount_t for vmaps and missed to change the vunmap
code to properly unset the vmap pointer, which is now cleared while vmap's
refcount > 0. Clear the cached vmap pointer only when refcounting drops to
zero to fix the bug.
Fixes: e1fc39a92332 ("drm/shmem-helper: Use refcount_t for vmap_use_count")
Reported-by: Lucas De Marchi <lucas.demar...@intel.com>
Closes:
https://lore.kernel.org/dri-devel/20250403105053.788b0...@collabora.com/T/#m3dca6d81bedc8d6146a56b82694624fbc6fa4c96
Signed-off-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 2d924d547a51..aa43265f4f4f 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -415,11 +415,11 @@ void drm_gem_shmem_vunmap_locked(struct
drm_gem_shmem_object *shmem,
if (refcount_dec_and_test(&shmem->vmap_use_count)) {
vunmap(shmem->vaddr);
+ shmem->vaddr = NULL;
+
drm_gem_shmem_unpin_locked(shmem);
}
}
-
- shmem->vaddr = NULL;
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_vunmap_locked);
--
2.49.0
