drm/panfrost: Fix shrinker list corruption by madvise IOCTL

commit 9fc33eaaa979d112d10fea729edcd2a2e21aa912 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 1ffaef5ec5ff51bb62364181b8bedcef0ff1e047..de533f3727648054b2de6881403c090741f45619 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -422,8 +422,8 @@ 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);
        }