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From: Alexander Sergeyev <sergeev917@gmail.com>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: Mario.Limonciello@dell.com, dvhart@infradead.org,
	andy@infradead.org, linux-kernel@vger.kernel.org,
	mjg59@srcf.ucam.org, platform-driver-x86@vger.kernel.org
Subject: Re: PROBLEM: NULL pointer dereference in dell_set_arguments() in 4.15
Date: Sun, 4 Feb 2018 19:29:54 +0300	[thread overview]
Message-ID: <20180204162954.GA24841@localhost.localdomain> (raw)
In-Reply-To: <20180204121530.sl3h77mxbwusp2ul@pali>

>To make dell_micmute_led_set() work properly we need to ensure that either WMI 
>or SMM driver is already loaded and initialized.

From the looks of the call trace dell_micmute_led_set() is called from device 
phase of initialization. Which means that there is a use of dell-laptop 
interface while the module is not initialized (since late_initcall). 
Previously, this led to crashes.

But dell_micmute_led_set() does not touch the module state now, so nothing is 
technically broken; dell-smbios and dell-smbios-smm use subsys_initcall, so 
they are ready. But WMI driver is in the same phase with intel hda, so there 
might be something there.

WARNING: multiple messages have this Message-ID (diff)
From: Alexander Sergeyev <sergeev917@gmail.com>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: Mario.Limonciello@dell.com, dvhart@infradead.org,
	andy@infradead.org, linux-kernel@vger.kernel.org,
	mjg59@srcf.ucam.org, platform-driver-x86@vger.kernel.org
Subject: Re: PROBLEM: NULL pointer dereference in dell_set_arguments() in 4.15
Date: Sun, 4 Feb 2018 19:29:54 +0300	[thread overview]
Message-ID: <20180204162954.GA24841@localhost.localdomain> (raw)
In-Reply-To: <20180204121530.sl3h77mxbwusp2ul@pali>

>To make dell_micmute_led_set() work properly we need to ensure that either WMI 
>or SMM driver is already loaded and initialized.

>From the looks of the call trace dell_micmute_led_set() is called from device 
phase of initialization. Which means that there is a use of dell-laptop 
interface while the module is not initialized (since late_initcall). 
Previously, this led to crashes.

But dell_micmute_led_set() does not touch the module state now, so nothing is 
technically broken; dell-smbios and dell-smbios-smm use subsys_initcall, so 
they are ready. But WMI driver is in the same phase with intel hda, so there 
might be something there.

  parent reply	other threads:[~2018-02-04 16:26 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-03 16:20 PROBLEM: NULL pointer dereference in dell_set_arguments() in 4.15 Alexander Sergeyev
2018-02-03 16:20 ` Alexander Sergeyev
2018-02-03 20:22 ` Alexander Sergeyev
2018-02-03 20:22   ` Alexander Sergeyev
     [not found] ` <e489f5ee-34e5-4777-afe7-38d31d2ad3fd@Dell.com>
2018-02-04  9:23   ` Alexander Sergeyev
2018-02-04 12:15     ` Pali Rohár
2018-02-04 14:25       ` Andy Shevchenko
2018-02-04 16:29       ` Alexander Sergeyev [this message]
2018-02-04 16:29         ` Alexander Sergeyev

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