On Mon, Jan 21, 2019 at 11:19 PM Yue Hu <[email protected]> wrote: > > From 7c1f672a2d7b7c2cfef313060bd429afc4af995b Mon Sep 17 00:00:00 2001 > From: Yue Hu <[email protected]> > Date: Tue, 22 Jan 2019 14:47:00 +0800 > Subject: [PATCH] pstore/ram: Avoid possible failure of dummy device unregister > > In ramoops_register_dummy() if create platform device of dummy > failed, the problem is following code called: > > dummy = NULL; > ramoops_unregister_dummy(); > > However platform_device_unregister() will check the pointer: > > void platform_device_del(struct platform_device *pdev) > { > int i; > > if (pdev) { > ... > } > } > void platform_device_put(struct platform_device *pdev) > { > if (pdev) > put_device(&pdev->dev); > } > void platform_device_unregister(struct platform_device *pdev) > { > platform_device_del(pdev); > platform_device_put(pdev); > } > > So the dummy device maybe always exists in the system, this is bad > case, we need to avoid it. > > Signed-off-by: Yue Hu <[email protected]> > --- > fs/pstore/ram.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c > index 8db1f7f..1d56a20 100644 > --- a/fs/pstore/ram.c > +++ b/fs/pstore/ram.c > @@ -932,7 +932,6 @@ static void __init ramoops_register_dummy(void) > if (IS_ERR(dummy)) { > pr_info("could not create platform device: %ld\n", > PTR_ERR(dummy)); > - dummy = NULL; > ramoops_unregister_dummy();
No, this needs to be cleared to NULL to avoid leaving a ERR_PTR (which are non-NULL, see IS_ERR() above it), so that it can be safe to unconditionally call platform_device_unregister(). -- Kees Cook
