Re: 2.6.24-rc1: OOPS at acpi_battery_update

[Alexey Starikovskiy <aystarik@gmail.com>]

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Andrew,

I can not contact with Len for several days, while the oops on battery 
seems quite important.
It also seem to behave well in -mm tree (as part of Len's acpi-test).
Will you send this patch to Linus without approval from Len or should I?

Thanks,
Alex.

Andrew Morton wrote:
> On Fri, 09 Nov 2007 12:36:43 +0300 Alexey Starikovskiy <astarikovskiy@suse.de> wrote:
>
>   
>> Andrew Morton wrote:
>>     
>>> A> On Thu, 08 Nov 2007 19:35:23 +0300 Alexey Starikovskiy <astarikovskiy@suse.de> wrote:
>>>       
>>>> [remove_cycle_at_battery_removal.patch  text/x-patch (1.7KB)]
>>>> ACPI: Battery: remove cycle from battery removal.
>>>>
>>>> From: Alexey Starikovskiy <astarikovskiy@suse.de>
>>>>
>>>> get_property() should not call battery_update() on absent battery to
>>>> avoid cycle and oops.
>>>>
>>>> Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
>>>> Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
>>>>         
>>> A patch similar to this one but with an identical changelog was merged into
>>> Len's tree on November 2.
>>>
>>> If it had been promptly merged into mainline then quite a lot of people's
>>> time would not have been wasted.
>>>
>>>       
>> Andrew,
>> should I send such patches directly to you/Linus?
>>
>>     
>
> Well if Len doesn't object and you're confident in the changes, why not? 
> Any time we leave bugs unfixed we drive away testers and that impacts all
> parts of the kernel.
>
>   


[-- Attachment #2: remove_cycle_at_battery_removal.patch --]
[-- Type: text/x-patch, Size: 1733 bytes --]

ACPI: Battery: remove cycle from battery removal.

From: Alexey Starikovskiy <astarikovskiy@suse.de>

get_property() should not call battery_update() on absent battery to
avoid cycle and oops.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
---

 drivers/acpi/battery.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index c2ce0ad..192c244 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -132,7 +132,7 @@ static int acpi_battery_technology(struct acpi_battery *battery)
 	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 }
 
-static int acpi_battery_update(struct acpi_battery *battery);
+static int acpi_battery_get_state(struct acpi_battery *battery);
 
 static int acpi_battery_get_property(struct power_supply *psy,
 				     enum power_supply_property psp,
@@ -140,10 +140,11 @@ static int acpi_battery_get_property(struct power_supply *psy,
 {
 	struct acpi_battery *battery = to_acpi_battery(psy);
 
-	if ((!acpi_battery_present(battery)) &&
-	     psp != POWER_SUPPLY_PROP_PRESENT)
+	if (acpi_battery_present(battery)) {
+		/* run battery update only if it is present */
+		acpi_battery_get_state(battery);
+	} else if (psp != POWER_SUPPLY_PROP_PRESENT)
 		return -ENODEV;
-	acpi_battery_update(battery);
 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
 		if (battery->state & 0x01)
@@ -457,6 +458,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
 		return;
 	device_remove_file(battery->bat.dev, &alarm_attr);
 	power_supply_unregister(&battery->bat);
+	battery->bat.dev = NULL;
 }
 
 static int acpi_battery_update(struct acpi_battery *battery)