From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Date: Thu, 30 Jun 2022 20:06:01 +0000 (+0300)
Subject: drm/panfrost: Fix shrinker list corruption by madvise IOCTL
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9fc33eaaa979d112d10fea729edcd2a2e21aa912;p=linux.git

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 087e69b98d069..b1e6d238674ff 100644
--- 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);
 	}