drm/panfrost: Fix shrinker list corruption by madvise IOCTL

Calling madvise IOCTL twice on BO causes memory shrinker list corruption
and crashes kernel because BO is already on the list and it's added to
the list again, while BO should be removed from the list before it's
re-added. Fix it.

Cc: stable@vger.kernel.org
Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220630200601.1884120-3-dmitry.osipenko@collabora.com

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 087e69b98d0694b8ce1037c8df8b7277e309b9e1..b1e6d238674ffc0bbf5a1ffb2b17ff1c8d8a2628 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -433,8 +433,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
 
        if (args->retained) {
                if (args->madv == PANFROST_MADV_DONTNEED)
-                       list_add_tail(&bo->base.madv_list,
-                                     &pfdev->shrinker_list);
+                       list_move_tail(&bo->base.madv_list,
+                                      &pfdev->shrinker_list);
                else if (args->madv == PANFROST_MADV_WILLNEED)
                        list_del_init(&bo->base.madv_list);
        }