Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 56/86] ACPI / power: Avoid maybe-uninitialized warning | Date | Thu, 4 May 2017 11:04:21 +0200 |
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From: Arnd Bergmann <arnd@arndb.de>
3.12-stable review patch. If anyone has any objections, please let me know.
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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: Jiri Slaby <jslaby@suse.cz> --- drivers/acpi/power.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index c2ad391d8041..4b35a115749c 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -204,6 +204,7 @@ 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; -- 2.12.2
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