If 2 threads change the MADVISE property of the same BO in parallel we
might end up with an shmem->madv value that's inconsistent with the
presence of the BO in the shrinker list.
The easiest solution to fix that is to protect the
drm_gem_shmem_madvise() call with the shrinker lock.
Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_drv.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index f21bc8a7ee3a..efc0a24d1f4c 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -347,20 +347,19 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
return -ENOENT;
}
+ mutex_lock(&pfdev->shrinker_lock);
args->retained = drm_gem_shmem_madvise(gem_obj, args->madv);
if (args->retained) {
struct panfrost_gem_object *bo = to_panfrost_bo(gem_obj);
- mutex_lock(&pfdev->shrinker_lock);
-
if (args->madv == PANFROST_MADV_DONTNEED)
- list_add_tail(&bo->base.madv_list, &pfdev->shrinker_list);
+ list_add_tail(&bo->base.madv_list,
+ &pfdev->shrinker_list);
else if (args->madv == PANFROST_MADV_WILLNEED)
list_del_init(&bo->base.madv_list);
-
- mutex_unlock(&pfdev->shrinker_lock);
}
+ mutex_unlock(&pfdev->shrinker_lock);
drm_gem_object_put_unlocked(gem_obj);
return 0;
--
2.23.0
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