From: Arnd Bergmann <[email protected]> commit fe8c470ab87d90e4b5115902dd94eced7e3305c3 upstream.
gcc -O2 cannot always prove that the loop in acpi_power_get_inferred_state() is enterered at least once, so it assumes that cur_state might not get initialized: drivers/acpi/power.c: In function 'acpi_power_get_inferred_state': drivers/acpi/power.c:222:9: error: 'cur_state' may be used uninitialized in this function [-Werror=maybe-uninitialized] This sets the variable to zero at the start of the loop, to ensure that there is well-defined behavior even for an empty list. This gets rid of the warning. The warning first showed up when the -Os flag got removed in a bug fix patch in linux-4.11-rc5. I would suggest merging this addon patch on top of that bug fix to avoid introducing a new warning in the stable kernels. Fixes: 61b79e16c68d (ACPI: Fix incompatibility with mcount-based function graph tracing) Signed-off-by: Arnd Bergmann <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]> Signed-off-by: Willy Tarreau <[email protected]> --- drivers/acpi/power.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index 288bb27..9954200 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -211,6 +211,7 @@ static int acpi_power_get_list_state(struct list_head *list, int *state) return -EINVAL; /* The state of the list is 'on' IFF all resources are 'on'. */ + cur_state = 0; list_for_each_entry(entry, list, node) { struct acpi_power_resource *resource = entry->resource; acpi_handle handle = resource->device.handle; -- 2.8.0.rc2.1.gbe9624a
