media: ti-vpe: cal: fix a kernel oops when unloading module

After the switch to use v4l2_async_notifier_add_subdev() and
v4l2_async_notifier_cleanup(), unloading the ti_cal module would cause a
kernel oops.

This was root cause to the fact that v4l2_async_notifier_cleanup() tries
to kfree the asd pointer passed into v4l2_async_notifier_add_subdev().

In our case the asd reference was from a statically allocated struct.
So in effect v4l2_async_notifier_cleanup() was trying to free a pointer
that was not kalloc.

So here we switch to using a kzalloc struct instead of a static one.
To achieve this we re-order some of the calls to prevent asd allocation
from leaking.

Fixes: d079f94c9046 ("media: platform: Switch to v4l2_async_notifier_add_subdev")
Cc: stable@vger.kernel.org
Signed-off-by: Benoit Parrot <bparrot@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
index 6d4cbb8..6c8f370 100644 (file)
--- a/drivers/media/platform/ti-vpe/cal.c
+++ b/drivers/media/platform/ti-vpe/cal.c
@@ -372,8 +372,6 @@ struct cal_ctx {
        struct v4l2_subdev      *sensor;
        struct v4l2_fwnode_endpoint     endpoint;
 
-       struct v4l2_async_subdev asd;
-
        struct v4l2_fh          fh;
        struct cal_dev          *dev;
        struct cc_data          *cc;
@@ -2032,7 +2030,6 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst)
 
        parent = pdev->dev.of_node;
 
-       asd = &ctx->asd;
        endpoint = &ctx->endpoint;
 
        ep_node = NULL;
@@ -2079,8 +2076,6 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst)
                ctx_dbg(3, ctx, "can't get remote parent\n");
                goto cleanup_exit;
        }
-       asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
-       asd->match.fwnode = of_fwnode_handle(sensor_node);
 
        v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep_node), endpoint);
 
@@ -2110,9 +2105,17 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst)
 
        v4l2_async_notifier_init(&ctx->notifier);
 
+       asd = kzalloc(sizeof(*asd), GFP_KERNEL);
+       if (!asd)
+               goto cleanup_exit;
+
+       asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+       asd->match.fwnode = of_fwnode_handle(sensor_node);
+
        ret = v4l2_async_notifier_add_subdev(&ctx->notifier, asd);
        if (ret) {
                ctx_err(ctx, "Error adding asd\n");
+               kfree(asd);
                goto cleanup_exit;
        }