Patch "i2c: remove __init from i2c_register_board_info()" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    i2c: remove __init from i2c_register_board_info()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-remove-__init-from-i2c_register_board_info.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5abe9b26847c65a698f38744a52635b287514294 Mon Sep 17 00:00:00 2001
From: "Luis R. Rodriguez" <mcgrof@kernel.org>
Date: Tue, 7 Jun 2016 16:52:27 -0700
Subject: i2c: remove __init from i2c_register_board_info()

From: Luis R. Rodriguez <mcgrof@kernel.org>

commit 5abe9b26847c65a698f38744a52635b287514294 upstream.

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@kernel.org>
[wsa: made function declaration a one-liner]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/i2c/i2c-boardinfo.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/i2c/i2c-boardinfo.c
+++ b/drivers/i2c/i2c-boardinfo.c
@@ -56,9 +56,7 @@ EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bu
  * The board info passed can safely be __initdata, but be careful of embedded
  * pointers (for platform_data, functions, etc) since that won't be copied.
  */
-int __init
-i2c_register_board_info(int busnum,
-	struct i2c_board_info const *info, unsigned len)
+int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
 {
 	int status;
 


Patches currently in stable-queue which might be from mcgrof@kernel.org are

queue-4.4/i2c-remove-__init-from-i2c_register_board_info.patch