diff options
| -rw-r--r-- | Documentation/DocBook/debugobjects.tmpl | 50 | ||||
| -rw-r--r-- | include/linux/debugobjects.h | 6 | ||||
| -rw-r--r-- | kernel/timer.c | 62 | ||||
| -rw-r--r-- | lib/debugobjects.c | 54 |
4 files changed, 162 insertions, 10 deletions
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/kernel/timer.c b/kernel/timer.c index 9c3c62b0c4b..a297ffcf888 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; @@ -480,12 +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) @@ -508,6 +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); @@ -531,6 +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) @@ -552,6 +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) @@ -902,6 +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); @@ -932,6 +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) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index a78b7c6e042..77cb245f8e7 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"); } /** @@ -563,6 +571,44 @@ out_unlock: } /** + * 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 * @descr: pointer to an object specific debug description structure |