linux-kernel - Re: [PATCH] i2c: remove __init from i2c_register_board

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Message-ID: <20160614221807.GH11948@wotan.suse.de>
Date:	Wed, 15 Jun 2016 00:18:07 +0200
From:	"Luis R. Rodriguez" <mcgrof@...nel.org>
To:	wsa@...-dreams.de
Cc:	wsa@...-dreams.de, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, feng.tang@...el.com,
	linux-next@...r.kernel.org, mcgrof@...nel.org
Subject: Re: [PATCH] i2c: remove __init from i2c_register_board_info()

On Tue, Jun 07, 2016 at 04:52:27PM -0700, Luis R. Rodriguez wrote:
> As of next-20160607 with allyesconfig we get this linker failure:
> 
>   MODPOST vmlinux.o
> WARNING: vmlinux.o(.text+0x21bc0d): Section mismatch in reference from
> the function intel_scu_devices_create() to the function
> .init.text:i2c_register_board_info()
> 
> This is caused by the fact that intel_scu_devices_create() calls
> i2c_register_board_info() and intel_scu_devices_create() is not
> annotated with __init. This typically involves manual code
> inspection and if one is certain this is correct we would
> just peg intel_scu_devices_create() with a __ref annotation.
> 
> In this case this would be wrong though as the
> intel_scu_devices_create() call is exported, and used in
> the ipc_probe() on drivers/platform/x86/intel_scu_ipc.c.
> The issue is that even though builtin_pci_driver(ipc_driver)
> is used this just exposes the probe routine, which can occur
> at any point in time if this bus supports hotplug. A race
> can happen between kernel_init_freeable() that calls the init
> calls (in this case registeres the intel_scu_ipc.c driver, and
> later free_initmem(), which would free the i2c_register_board_info().
> If a probe happens later in boot i2c_register_board_info() would
> not be present and we should get a page fault.
> 
> Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>

I don't see this merged yet on linux-next and this is still an issue.

 *Poke*

  Luis