From feac18dda25134005909e7770c77464e65608bd8 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Mon, 7 Nov 2011 19:48:26 -0800
Subject: 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.
[ tglx@linutronix.de: Split out the debugobjects vs. the timer change ]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Christine Chan <cschan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1320724108-20788-2-git-send-email-sboyd@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
lib/debugobjects.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
(limited to 'lib/debugobjects.c')
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index a78b7c6e042..b7a530504b3 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -268,12 +268,16 @@ static void debug_print_object(struct debug_obj *obj, char *msg)
* Try to repair the damage, so we have a better chance to get useful
* debug output.
*/
-static void
+static int
debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
void * addr, enum debug_obj_state state)
{
+ int fixed = 0;
+
if (fixup)
- debug_objects_fixups += fixup(addr, state);
+ fixed = fixup(addr, state);
+ debug_objects_fixups += fixed;
+ return fixed;
}
static void debug_object_is_on_stack(void *addr, int onstack)
@@ -386,6 +390,9 @@ void debug_object_activate(void *addr, struct debug_obj_descr *descr)
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
+ struct debug_obj o = { .object = addr,
+ .state = ODEBUG_STATE_NOTAVAILABLE,
+ .descr = descr };
if (!debug_objects_enabled)
return;
@@ -425,8 +432,9 @@ void debug_object_activate(void *addr, struct debug_obj_descr *descr)
* let the type specific code decide whether this is
* true or not.
*/
- debug_object_fixup(descr->fixup_activate, addr,
- ODEBUG_STATE_NOTAVAILABLE);
+ if (debug_object_fixup(descr->fixup_activate, addr,
+ ODEBUG_STATE_NOTAVAILABLE))
+ debug_print_object(&o, "activate");
}
/**
--
cgit v1.2.3-70-g09d2
From b84d435cc228e87951f3bbabf6cc4a5f25d5fb16 Mon Sep 17 00:00:00 2001
From: Christine Chan <cschan@codeaurora.org>
Date: Mon, 7 Nov 2011 19:48:27 -0800
Subject: debugobjects: Extend to assert that an object is initialized
Calling del_timer_sync() on an uninitialized timer leads to a
never ending loop in lock_timer_base() that spins checking for a
non-NULL timer base. Add an assertion to debugobjects to catch
usage of uninitialized objects so that we can initialize timers
in the del_timer_sync() path before it calls lock_timer_base().
[ sboyd@codeaurora.org: Clarify commit message ]
Signed-off-by: Christine Chan <cschan@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1320724108-20788-3-git-send-email-sboyd@codeaurora.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
Documentation/DocBook/debugobjects.tmpl | 50 +++++++++++++++++++++++++++++++++
include/linux/debugobjects.h | 6 ++++
lib/debugobjects.c | 38 +++++++++++++++++++++++++
3 files changed, 94 insertions(+)
(limited to 'lib/debugobjects.c')
diff --git a/Documentation/DocBook/debugobjects.tmpl b/Documentation/DocBook/debugobjects.tmpl
index 08ff908aa7a..24979f691e3 100644
--- a/Documentation/DocBook/debugobjects.tmpl
+++ b/Documentation/DocBook/debugobjects.tmpl
@@ -96,6 +96,7 @@
<listitem><para>debug_object_deactivate</para></listitem>
<listitem><para>debug_object_destroy</para></listitem>
<listitem><para>debug_object_free</para></listitem>
+ <listitem><para>debug_object_assert_init</para></listitem>
</itemizedlist>
Each of these functions takes the address of the real object and
a pointer to the object type specific debug description
@@ -273,6 +274,26 @@
debug checks.
</para>
</sect1>
+
+ <sect1 id="debug_object_assert_init">
+ <title>debug_object_assert_init</title>
+ <para>
+ This function is called to assert that an object has been
+ initialized.
+ </para>
+ <para>
+ When the real object is not tracked by debugobjects, it calls
+ fixup_assert_init of the object type description structure
+ provided by the caller, with the hardcoded object state
+ ODEBUG_NOT_AVAILABLE. The fixup function can correct the problem
+ by calling debug_object_init and other specific initializing
+ functions.
+ </para>
+ <para>
+ When the real object is already tracked by debugobjects it is
+ ignored.
+ </para>
+ </sect1>
</chapter>
<chapter id="fixupfunctions">
<title>Fixup functions</title>
@@ -381,6 +402,35 @@
statistics.
</para>
</sect1>
+ <sect1 id="fixup_assert_init">
+ <title>fixup_assert_init</title>
+ <para>
+ This function is called from the debug code whenever a problem
+ in debug_object_assert_init is detected.
+ </para>
+ <para>
+ Called from debug_object_assert_init() with a hardcoded state
+ ODEBUG_STATE_NOTAVAILABLE when the object is not found in the
+ debug bucket.
+ </para>
+ <para>
+ The function returns 1 when the fixup was successful,
+ otherwise 0. The return value is used to update the
+ statistics.
+ </para>
+ <para>
+ Note, this function should make sure debug_object_init() is
+ called before returning.
+ </para>
+ <para>
+ The handling of statically initialized objects is a special
+ case. The fixup function should check if this is a legitimate
+ case of a statically initialized object or not. In this case only
+ debug_object_init() should be called to make the object known to
+ the tracker. Then the function should return 0 because this is not
+ a real fixup.
+ </para>
+ </sect1>
</chapter>
<chapter id="bugs">
<title>Known Bugs And Assumptions</title>
diff --git a/include/linux/debugobjects.h b/include/linux/debugobjects.h
index 65970b811e2..0e5f5785d9f 100644
--- a/include/linux/debugobjects.h
+++ b/include/linux/debugobjects.h
@@ -46,6 +46,8 @@ struct debug_obj {
* fails
* @fixup_free: fixup function, which is called when the free check
* fails
+ * @fixup_assert_init: fixup function, which is called when the assert_init
+ * check fails
*/
struct debug_obj_descr {
const char *name;
@@ -54,6 +56,7 @@ struct debug_obj_descr {
int (*fixup_activate) (void *addr, enum debug_obj_state state);
int (*fixup_destroy) (void *addr, enum debug_obj_state state);
int (*fixup_free) (void *addr, enum debug_obj_state state);
+ int (*fixup_assert_init)(void *addr, enum debug_obj_state state);
};
#ifdef CONFIG_DEBUG_OBJECTS
@@ -64,6 +67,7 @@ extern void debug_object_activate (void *addr, struct debug_obj_descr *descr);
extern void debug_object_deactivate(void *addr, struct debug_obj_descr *descr);
extern void debug_object_destroy (void *addr, struct debug_obj_descr *descr);
extern void debug_object_free (void *addr, struct debug_obj_descr *descr);
+extern void debug_object_assert_init(void *addr, struct debug_obj_descr *descr);
/*
* Active state:
@@ -89,6 +93,8 @@ static inline void
debug_object_destroy (void *addr, struct debug_obj_descr *descr) { }
static inline void
debug_object_free (void *addr, struct debug_obj_descr *descr) { }
+static inline void
+debug_object_assert_init(void *addr, struct debug_obj_descr *descr) { }
static inline void debug_objects_early_init(void) { }
static inline void debug_objects_mem_init(void) { }
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index b7a530504b3..77cb245f8e7 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -570,6 +570,44 @@ out_unlock:
raw_spin_unlock_irqrestore(&db->lock, flags);
}
+/**
+ * debug_object_assert_init - debug checks when object should be init-ed
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
+{
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+
+ if (!debug_objects_enabled)
+ return;
+
+ db = get_bucket((unsigned long) addr);
+
+ raw_spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (!obj) {
+ struct debug_obj o = { .object = addr,
+ .state = ODEBUG_STATE_NOTAVAILABLE,
+ .descr = descr };
+
+ raw_spin_unlock_irqrestore(&db->lock, flags);
+ /*
+ * Maybe the object is static. Let the type specific
+ * code decide what to do.
+ */
+ if (debug_object_fixup(descr->fixup_assert_init, addr,
+ ODEBUG_STATE_NOTAVAILABLE))
+ debug_print_object(&o, "assert_init");
+ return;
+ }
+
+ raw_spin_unlock_irqrestore(&db->lock, flags);
+}
+
/**
* debug_object_active_state - debug checks object usage state machine
* @addr: address of the object
--
cgit v1.2.3-70-g09d2
From 9f78ff005a6b6313728247113948450b2adddde8 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Mon, 5 Mar 2012 14:59:17 -0800
Subject: debugobjects: Fix selftest for static warnings
debugobjects is now printing a warning when a fixup for a NOTAVAILABLE
object is run. This causes the selftest to fail like:
ODEBUG: selftest warnings failed 4 != 5
We could just increase the number of warnings that the selftest is
expecting to see because that is actually what has changed. But, it turns
out that fixup_activate() was written with inverted logic and thus a fixup
for a static object returned 1 indicating the object had been fixed, and 0
otherwise. Fix the logic to be correct and update the counts to reflect
that nothing needed fixing for a static object.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/debugobjects.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
(limited to 'lib/debugobjects.c')
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 77cb245f8e7..0ab9ae8057f 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))
--
cgit v1.2.3-70-g09d2