Commit fe8c470a authored Apr 19, 2017 by Arnd Bergmann Committed by Rafael J. Wysocki Apr 19, 2017

ACPI / power: Avoid maybe-uninitialized warning



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: 61b79e16 (ACPI: Fix incompatibility with mcount-based function graph tracing)
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 4f7d029b

drivers/acpi/power.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -200,6 +200,7 @@ 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;

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