Re: [PATCH] platform/x86: thinkpad_acpi: Fix NULL pointer dereferences while probing

From: "Kurt Borja" <kuurtb@gmail.com>
To: "Kurt Borja" <kuurtb@gmail.com>,
	"Henrique de Moraes Holschuh" <hmh@hmh.eng.br>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	"Mark Pearson" <mpearson-lenovo@squebb.ca>
Cc: <ibm-acpi-devel@lists.sourceforge.net>,
	<platform-driver-x86@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-riscv@lists.infradead.org>,
	"Damian Tometzki" <damian@riscv-rocks.de>
Subject: Re: [PATCH] platform/x86: thinkpad_acpi: Fix NULL pointer dereferences while probing
Date: Sun, 30 Mar 2025 15:43:40 -0300	[thread overview]
Message-ID: <D8TTMCQBDYX3.H8ACLTS7KL19@gmail.com> (raw)
In-Reply-To: <20250330-thinkpad-fix-v1-1-4906b3fe6b74@gmail.com>

On Sun Mar 30, 2025 at 12:39 PM -03, Kurt Borja wrote:
> Some subdrivers make use of the global reference tpacpi_pdev during
> initialization, which is called from the platform driver's probe.
> However, after
>
> commit 38b9ab80db31 ("platform/x86: thinkpad_acpi: Move subdriver initialization to tpacpi_pdriver's probe.")
>
> this variable is only properly initialized *after* probing and this can
> result in a NULL pointer dereference.
>
> In order to fix this without reverting the commit, register the platform
> bundle in two steps, first create and initialize tpacpi_pdev, then
> register the driver synchronously with platform_driver_probe(). This way
> the benefits of commit 38b9ab80db31 are preserved.
>
> Additionally,
>
> commit 43fc63a1e8f6 ("platform/x86: thinkpad_acpi: Move HWMON initialization to tpacpi_hwmon_pdriver's probe")
>
> introduced a similar problem, however tpacpi_sensors_pdev is only used
> once inside the probe, so replace the global reference with the one
> given by the probe.

I don't understand why b4 added the linux-riscv list to the recipients,
but it was definitely not inteded.

Sorry for the noise.

-- 
 ~ Kurt

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