Patch "ACPI / power: Avoid maybe-uninitialized warning" has been added to the 4.4-stable tree

Patch "ACPI / power: Avoid maybe-uninitialized warning" has been added to the 4.4-stable tree

[gregkh]

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

    ACPI / power: Avoid maybe-uninitialized warning

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:
     acpi-power-avoid-maybe-uninitialized-warning.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 fe8c470ab87d90e4b5115902dd94eced7e3305c3 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 19 Apr 2017 19:47:04 +0200
Subject: ACPI / power: Avoid maybe-uninitialized warning

From: Arnd Bergmann <arnd@arndb.de>

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 <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/power.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -200,6 +200,7 @@ static int acpi_power_get_list_state(str
 		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;


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/acpi-power-avoid-maybe-uninitialized-warning.patch