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timer: Use debugobjects to catch deletion of uninitialized timers 

del_timer_sync() calls debug_object_assert_init() to assert that
a timer has been initialized before calling lock_timer_base().
lock_timer_base() would spin forever on a NULL(uninit-ed) base.
The check is added to del_timer() to prevent silent failure, even
though it would not get stuck in an infinite loop.

[ sboyd@codeaurora.org: Remove WARN, intialize timer function]

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/1320724108-20788-4-git-send-email-sboyd@codeaurora.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Christine Chan 2011-11-07 19:48:28 -08:00 committed by Thomas Gleixner
parent fb16b8cf0b
commit dc4218bd0f
1 changed files with 48 additions and 5 deletions
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53
kernel/timer.c
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@ -487,12 +487,40 @@ static int timer_fixup_free(void *addr, enum debug_obj_state state)
}
}
/*
* fixup_assert_init is called when:
* - an untracked/uninit-ed object is found
*/
static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
{
struct timer_list *timer = addr;
switch (state) {
case ODEBUG_STATE_NOTAVAILABLE:
if (timer->entry.prev == TIMER_ENTRY_STATIC) {
/*
* This is not really a fixup. The timer was
* statically initialized. We just make sure that it
* is tracked in the object tracker.
*/
debug_object_init(timer, &timer_debug_descr);
return 0;
} else {
setup_timer(timer, stub_timer, 0);
return 1;
}
default:
return 0;
}
}
static struct debug_obj_descr timer_debug_descr = {
.name = "timer_list",
.debug_hint = timer_debug_hint,
.fixup_init = timer_fixup_init,
.fixup_activate = timer_fixup_activate,
.fixup_free = timer_fixup_free,
.name = "timer_list",
.debug_hint = timer_debug_hint,
.fixup_init = timer_fixup_init,
.fixup_activate = timer_fixup_activate,
.fixup_free = timer_fixup_free,
.fixup_assert_init = timer_fixup_assert_init,
};
static inline void debug_timer_init(struct timer_list *timer)
@ -515,6 +543,11 @@ static inline void debug_timer_free(struct timer_list *timer)
debug_object_free(timer, &timer_debug_descr);
}
static inline void debug_timer_assert_init(struct timer_list *timer)
{
debug_object_assert_init(timer, &timer_debug_descr);
}
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
@ -538,6 +571,7 @@ EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
static inline void debug_timer_init(struct timer_list *timer) { }
static inline void debug_timer_activate(struct timer_list *timer) { }
static inline void debug_timer_deactivate(struct timer_list *timer) { }
static inline void debug_timer_assert_init(struct timer_list *timer) { }
#endif
static inline void debug_init(struct timer_list *timer)
@ -559,6 +593,11 @@ static inline void debug_deactivate(struct timer_list *timer)
trace_timer_cancel(timer);
}
static inline void debug_assert_init(struct timer_list *timer)
{
debug_timer_assert_init(timer);
}
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
@ -909,6 +948,8 @@ int del_timer(struct timer_list *timer)
unsigned long flags;
int ret = 0;
debug_assert_init(timer);
timer_stats_timer_clear_start_info(timer);
if (timer_pending(timer)) {
base = lock_timer_base(timer, &flags);
@ -939,6 +980,8 @@ int try_to_del_timer_sync(struct timer_list *timer)
unsigned long flags;
int ret = -1;
debug_assert_init(timer);
base = lock_timer_base(timer, &flags);
if (base->running_timer == timer)