From dc4218bd0fe499fce2896f88101ea42dac1f60fc Mon Sep 17 00:00:00 2001 From: Christine Chan Date: Mon, 7 Nov 2011 19:48:28 -0800 Subject: 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 Signed-off-by: Stephen Boyd Cc: John Stultz Link: http://lkml.kernel.org/r/1320724108-20788-4-git-send-email-sboyd@codeaurora.org Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/timer.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 48 insertions(+), 5 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index 317087d5d5f..5fc5a766ba1 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -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) -- cgit v1.2.3