From: Yunxiang Li Yunxiang.Li@amd.com
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 Yunxiang.Li@amd.com Reviewed-by: Christian König christian.koenig@amd.com CC: stable@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20230622141902.28718-3-Yunxian... Signed-off-by: Christian König christian.koenig@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/ttm/ttm_resource.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- 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(s 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 { 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) {