6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Vasut <marex@xxxxxxx> [ Upstream commit eb2f932100288dbb881eadfed02e1459c6b9504c ] When translating source to sink streams in the crossbar subdev, the driver tries to locate the remote subdev connected to the sink pad. The remote pad may be NULL, if userspace tries to enable a stream that ends at an unconnected crossbar sink. When that occurs, the driver dereferences the NULL pad, leading to a crash. Prevent the crash by checking if the pad is NULL before using it, and return an error if it is. Cc: stable@xxxxxxxxxxxxxxx # 6.1 Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver") Signed-off-by: Marek Vasut <marex@xxxxxxx> Reviewed-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> Reviewed-by: Fabio Estevam <festevam@xxxxxxxxx> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231201150614.63300-1-marex@xxxxxxx Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c index 575f173373887..1bb1334ec6f2b 100644 --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c @@ -160,8 +160,14 @@ mxc_isi_crossbar_xlate_streams(struct mxc_isi_crossbar *xbar, } pad = media_pad_remote_pad_first(&xbar->pads[sink_pad]); - sd = media_entity_to_v4l2_subdev(pad->entity); + if (!pad) { + dev_dbg(xbar->isi->dev, + "no pad connected to crossbar input %u\n", + sink_pad); + return ERR_PTR(-EPIPE); + } + sd = media_entity_to_v4l2_subdev(pad->entity); if (!sd) { dev_dbg(xbar->isi->dev, "no entity connected to crossbar input %u\n", -- 2.43.0