From 70a3015683b007a0db4a1e858791b69afd45fc83 Mon Sep 17 00:00:00 2001 From: Yunxiang Li Date: Thu, 22 Jun 2023 10:18:03 -0400 Subject: [PATCH] drm/ttm: fix bulk_move corruption when adding a entry MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 4481913607e58196c48a4fef5e6f45350684ec3c upstream. When the resource is the first in the bulk_move range, adding it again (thus moving it to the tail) will corrupt the list since the first pointer is not moved. This eventually lead to null pointer deref in ttm_lru_bulk_move_del() Fixes: fee2ede15542 ("drm/ttm: rework bulk move handling v5") Signed-off-by: Yunxiang Li Reviewed-by: Christian König CC: stable@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20230622141902.28718-3-Yunxiang.Li@amd.com Signed-off-by: Christian König Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/ttm/ttm_resource.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c index a729c32a1e48..3287032a2f8e 100644 --- a/drivers/gpu/drm/ttm/ttm_resource.c +++ b/drivers/gpu/drm/ttm/ttm_resource.c @@ -85,6 +85,8 @@ static void ttm_lru_bulk_move_pos_tail(struct ttm_lru_bulk_move_pos *pos, struct ttm_resource *res) { if (pos->last != res) { + if (pos->first == res) + pos->first = list_next_entry(res, lru); list_move(&res->lru, &pos->last->lru); pos->last = res; } @@ -110,7 +112,8 @@ static void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk, { struct ttm_lru_bulk_move_pos *pos = ttm_lru_bulk_move_pos(bulk, res); - if (unlikely(pos->first == res && pos->last == res)) { + if (unlikely(WARN_ON(!pos->first || !pos->last) || + (pos->first == res && pos->last == res))) { pos->first = NULL; pos->last = NULL; } else if (pos->first == res) {