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Date: Fri, 08 May 2026 02:03:44 +0200
Message-Id: <DICUSYTHZ339.3DW3CRNZ32K6U@kernel.org>
Subject: Re: [PATCH] device property: set fwnode->secondary to NULL in
 fwnode_init()
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, "Rafael J. Wysocki"
 <rafael@kernel.org>, "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
 "Daniel Scally" <djrscally@gmail.com>, "Heikki Krogerus"
 <heikki.krogerus@linux.intel.com>, "Sakari Ailus"
 <sakari.ailus@linux.intel.com>, "Len Brown" <lenb@kernel.org>, "Rob
 Herring" <robh@kernel.org>, "Saravana Kannan" <saravanak@kernel.org>,
 <driver-core@lists.linux.dev>, <linux-acpi@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, <brgl@kernel.org>, <stable@vger.kernel.org>
To: "Bartosz Golaszewski" <bartosz.golaszewski@oss.qualcomm.com>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20260506115701.23035-1-bartosz.golaszewski@oss.qualcomm.com>
In-Reply-To: <20260506115701.23035-1-bartosz.golaszewski@oss.qualcomm.com>

On Wed May 6, 2026 at 1:57 PM CEST, Bartosz Golaszewski wrote:
> If a firmware node is allocated on the stack (for instance: temporary
> software node whose life-time we control) or on the heap - but using a
> non-zeroing allocation function - and initialized using fwnode_init(),
> its secondary pointer will contain uninitalized memory which likely will
> be neither NULL nor IS_ERR().

I see why secondary is generally more prone to this, but if the justificati=
on of
this change is to not rely on the caller to zero out the memory, then we mi=
ght
just want to initialize all fields.

For instance, if the caller is allowed to not zero-initialize the memory th=
en
having flags with a random value isn't correct either; all accessors are at=
omic
bitwise operations that never zero the whole field.