[PATCHv2 1/3] debugobjects: Be smarter about static objects

Stephen Boyd
2011-11-08T03:48:58Z

Remove the WARN_ON() in timer_fixup_activate() and actually use
the return code from fixup to tell the debugobjects code to print
a warning. This provides better diagnostic information via a nice
debugobjects warning instead of a simple WARN_ON(1) in the timer
code with no information as to what is wrong. We also assign a
dummy timer callback so that if the timer is actually set to
fire we don't oops.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Christine Chan <cschan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
kernel/timer.c | 9 ++++++++-
lib/debugobjects.c | 15 +++++++++++----
2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/kernel/timer.c b/kernel/timer.c
index dbaa624..317087d 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -427,6 +427,12 @@ static int timer_fixup_init(void *addr, enum debug_obj_state state)
}
}

+/* Stub timer callback for improperly used timers. */
+static void stub_timer(unsigned long data)
+{
+ WARN_ON(1);
+}
+
/*
* fixup_activate is called when:
* - an active object is activated
@@ -450,7 +456,8 @@ static int timer_fixup_activate(void *addr, enum debug_obj_state state)
debug_object_activate(timer, &timer_debug_descr);
return 0;
} else {
- WARN_ON_ONCE(1);
+ setup_timer(timer, stub_timer, 0);
+ return 1;
}
return 0;

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index a78b7c6..0b07cc5 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -268,12 +268,15 @@ 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 +389,9 @@ 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 +431,9 @@ 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");
}

/**