From: "Luis R. Rodriguez" mcgrof@kernel.org
This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.
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[ Upstream commit 5abe9b26847c65a698f38744a52635b287514294 ]
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: Sasha Levin alexander.levin@microsoft.com --- drivers/i2c/i2c-boardinfo.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/i2c/i2c-boardinfo.c b/drivers/i2c/i2c-boardinfo.c index 90e322959303..42c25aed671d 100644 --- a/drivers/i2c/i2c-boardinfo.c +++ b/drivers/i2c/i2c-boardinfo.c @@ -56,9 +56,7 @@ EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); * 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;