Re: [tip:core/debugobjects] debugobjects: Be smarter about static objects

Stephen Boyd
2011-12-13T19:36:43Z

On 12/13/11 02:38, Thomas Gleixner wrote:
> Stephen,
>
> On Mon, 28 Nov 2011, tip-bot for Stephen Boyd wrote:
>
>> Commit-ID: feac18dda25134005909e7770c77464e65608bd8
>> Gitweb: http://git.kernel.org/tip/feac18dda25134005909e7770c77464e65608bd8
>> Author: Stephen Boyd <sboyd@codeaurora.org>
>> AuthorDate: Mon, 7 Nov 2011 19:48:26 -0800
>> Committer: Thomas Gleixner <tglx@linutronix.de>
>> CommitDate: Wed, 23 Nov 2011 18:49:22 +0100
>>
>> debugobjects: Be smarter about static objects
>>
>> Make debugobjects use the return code from the fixup function. That
>> allows us better diagnostics in the activate check than relying on a
>> WARN_ON() in the object specific code.
> that series wreckaged the debugobjects selftest. Can you please have a
> look?
>
> [ 0.000000] ODEBUG: selftest warnings failed 4 != 5
>
>

Thanks, I should have run the selftest :-(

This code is only slightly confusing

static int __init fixup_activate(void *addr, enum debug_obj_state state)
{
struct self_test *obj = addr;

switch (state) {
case ODEBUG_STATE_NOTAVAILABLE:
if (obj->static_init == 1) {
debug_object_init(obj, &descr_type_test);
debug_object_activate(obj, &descr_type_test);
/*
* Real code should return 0 here ! This is
* not a fixup of some bad behaviour. We
* merily call the debug_init function to keep
* track of the object.
*/
return 1;
} else {
/* Real code needs to emit a warning here */
}
return 0;

It seems that it does the complete opposite of what it should do, i.e.
return 1 when the fixup is static and not actually a problem and return
0 otherwise. Because of this return 1, debug_object_activate() thinks
there was a problem in the fixup and then it ups the warning count
because this patch added a warning print for static objects.

I see two solutions:

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 77cb245..a79083e 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -967,7 +967,7 @@ static void __init debug_objects_selftest(void)

obj.static_init = 1;
debug_object_activate(&obj, &descr_type_test);
- if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, warnings))
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
goto out;
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))

This would just up the warning count to take into account that a warning
is now printed when the state is NOTAVAILABLE and the fixup returns 1.

Or

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 77cb245..0ab9ae8 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -818,17 +818,9 @@ static int __init fixup_activate(void *addr, enum debug_obj_state state)
if (obj->static_init == 1) {
debug_object_init(obj, &descr_type_test);
debug_object_activate(obj, &descr_type_test);
- /*
- * Real code should return 0 here ! This is
- * not a fixup of some bad behaviour. We
- * merily call the debug_init function to keep
- * track of the object.
- */
- return 1;
- } else {
- /* Real code needs to emit a warning here */
+ return 0;
}
- return 0;
+ return 1;

case ODEBUG_STATE_ACTIVE:
debug_object_deactivate(obj, &descr_type_test);
@@ -967,7 +959,7 @@ static void __init debug_objects_selftest(void)

obj.static_init = 1;
debug_object_activate(&obj, &descr_type_test);
- if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, warnings))
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
goto out;
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))

This would make the fixup function for a static NOTAVAILABLE object
return 0 and 1 appropriately and corrects the fixup and warning checking
to reflect that nothing was in need of fixing.

Why was the fixup for selftest inverted?