diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 150 | ||||
| -rw-r--r-- | lib/debugobjects.c | 141 |
2 files changed, 174 insertions, 117 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 64155e310a9f..4f7b3a11eb4d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1034,69 +1034,20 @@ config DEBUG_PREEMPT menu "Lock Debugging (spinlocks, mutexes, etc...)" -config DEBUG_RT_MUTEXES - bool "RT Mutex debugging, deadlock detection" - depends on DEBUG_KERNEL && RT_MUTEXES - help - This allows rt mutex semantics violations and rt mutex related - deadlocks (lockups) to be detected and reported automatically. - -config DEBUG_SPINLOCK - bool "Spinlock and rw-lock debugging: basic checks" - depends on DEBUG_KERNEL - select UNINLINE_SPIN_UNLOCK - help - Say Y here and build SMP to catch missing spinlock initialization - and certain other kinds of spinlock errors commonly made. This is - best used in conjunction with the NMI watchdog so that spinlock - deadlocks are also debuggable. - -config DEBUG_MUTEXES - bool "Mutex debugging: basic checks" - depends on DEBUG_KERNEL - help - This feature allows mutex semantics violations to be detected and - reported. - -config DEBUG_WW_MUTEX_SLOWPATH - bool "Wait/wound mutex debugging: Slowpath testing" - depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT - select DEBUG_LOCK_ALLOC - select DEBUG_SPINLOCK - select DEBUG_MUTEXES - help - This feature enables slowpath testing for w/w mutex users by - injecting additional -EDEADLK wound/backoff cases. Together with - the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this - will test all possible w/w mutex interface abuse with the - exception of simply not acquiring all the required locks. - Note that this feature can introduce significant overhead, so - it really should not be enabled in a production or distro kernel, - even a debug kernel. If you are a driver writer, enable it. If - you are a distro, do not. - -config DEBUG_LOCK_ALLOC - bool "Lock debugging: detect incorrect freeing of live locks" - depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT - select DEBUG_SPINLOCK - select DEBUG_MUTEXES - select DEBUG_RT_MUTEXES if RT_MUTEXES - select LOCKDEP - help - This feature will check whether any held lock (spinlock, rwlock, - mutex or rwsem) is incorrectly freed by the kernel, via any of the - memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), - vfree(), etc.), whether a live lock is incorrectly reinitialized via - spin_lock_init()/mutex_init()/etc., or whether there is any lock - held during task exit. +config LOCK_DEBUGGING_SUPPORT + bool + depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + default y config PROVE_LOCKING bool "Lock debugging: prove locking correctness" - depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select LOCKDEP select DEBUG_SPINLOCK select DEBUG_MUTEXES select DEBUG_RT_MUTEXES if RT_MUTEXES + select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER + select DEBUG_WW_MUTEX_SLOWPATH select DEBUG_LOCK_ALLOC select TRACE_IRQFLAGS default n @@ -1134,20 +1085,9 @@ config PROVE_LOCKING For more details, see Documentation/locking/lockdep-design.txt. -config LOCKDEP - bool - depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT - select STACKTRACE - select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE && !X86 - select KALLSYMS - select KALLSYMS_ALL - -config LOCKDEP_SMALL - bool - config LOCK_STAT bool "Lock usage statistics" - depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select LOCKDEP select DEBUG_SPINLOCK select DEBUG_MUTEXES @@ -1167,6 +1107,80 @@ config LOCK_STAT CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. (CONFIG_LOCKDEP defines "acquire" and "release" events.) +config DEBUG_RT_MUTEXES + bool "RT Mutex debugging, deadlock detection" + depends on DEBUG_KERNEL && RT_MUTEXES + help + This allows rt mutex semantics violations and rt mutex related + deadlocks (lockups) to be detected and reported automatically. + +config DEBUG_SPINLOCK + bool "Spinlock and rw-lock debugging: basic checks" + depends on DEBUG_KERNEL + select UNINLINE_SPIN_UNLOCK + help + Say Y here and build SMP to catch missing spinlock initialization + and certain other kinds of spinlock errors commonly made. This is + best used in conjunction with the NMI watchdog so that spinlock + deadlocks are also debuggable. + +config DEBUG_MUTEXES + bool "Mutex debugging: basic checks" + depends on DEBUG_KERNEL + help + This feature allows mutex semantics violations to be detected and + reported. + +config DEBUG_WW_MUTEX_SLOWPATH + bool "Wait/wound mutex debugging: Slowpath testing" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select DEBUG_LOCK_ALLOC + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + help + This feature enables slowpath testing for w/w mutex users by + injecting additional -EDEADLK wound/backoff cases. Together with + the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this + will test all possible w/w mutex interface abuse with the + exception of simply not acquiring all the required locks. + Note that this feature can introduce significant overhead, so + it really should not be enabled in a production or distro kernel, + even a debug kernel. If you are a driver writer, enable it. If + you are a distro, do not. + +config DEBUG_RWSEMS + bool "RW Semaphore debugging: basic checks" + depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER + help + This debugging feature allows mismatched rw semaphore locks and unlocks + to be detected and reported. + +config DEBUG_LOCK_ALLOC + bool "Lock debugging: detect incorrect freeing of live locks" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + select DEBUG_RT_MUTEXES if RT_MUTEXES + select LOCKDEP + help + This feature will check whether any held lock (spinlock, rwlock, + mutex or rwsem) is incorrectly freed by the kernel, via any of the + memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), + vfree(), etc.), whether a live lock is incorrectly reinitialized via + spin_lock_init()/mutex_init()/etc., or whether there is any lock + held during task exit. + +config LOCKDEP + bool + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select STACKTRACE + select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE && !X86 + select KALLSYMS + select KALLSYMS_ALL + +config LOCKDEP_SMALL + bool + config DEBUG_LOCKDEP bool "Lock dependency engine debugging" depends on DEBUG_KERNEL && LOCKDEP diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 2f5349c6e81a..994be4805cec 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -42,14 +42,18 @@ static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata; static DEFINE_RAW_SPINLOCK(pool_lock); static HLIST_HEAD(obj_pool); +static HLIST_HEAD(obj_to_free); static int obj_pool_min_free = ODEBUG_POOL_SIZE; static int obj_pool_free = ODEBUG_POOL_SIZE; static int obj_pool_used; static int obj_pool_max_used; +/* The number of objs on the global free list */ +static int obj_nr_tofree; static struct kmem_cache *obj_cache; static int debug_objects_maxchain __read_mostly; +static int __maybe_unused debug_objects_maxchecked __read_mostly; static int debug_objects_fixups __read_mostly; static int debug_objects_warnings __read_mostly; static int debug_objects_enabled __read_mostly @@ -96,12 +100,32 @@ static const char *obj_states[ODEBUG_STATE_MAX] = { static void fill_pool(void) { gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN; - struct debug_obj *new; + struct debug_obj *new, *obj; unsigned long flags; if (likely(obj_pool_free >= debug_objects_pool_min_level)) return; + /* + * Reuse objs from the global free list; they will be reinitialized + * when allocating. + */ + while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) { + raw_spin_lock_irqsave(&pool_lock, flags); + /* + * Recheck with the lock held as the worker thread might have + * won the race and freed the global free list already. + */ + if (obj_nr_tofree) { + obj = hlist_entry(obj_to_free.first, typeof(*obj), node); + hlist_del(&obj->node); + obj_nr_tofree--; + hlist_add_head(&obj->node, &obj_pool); + obj_pool_free++; + } + raw_spin_unlock_irqrestore(&pool_lock, flags); + } + if (unlikely(!obj_cache)) return; @@ -177,62 +201,76 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr) * workqueue function to free objects. * * To reduce contention on the global pool_lock, the actual freeing of - * debug objects will be delayed if the pool_lock is busy. We also free - * the objects in a batch of 4 for each lock/unlock cycle. + * debug objects will be delayed if the pool_lock is busy. */ -#define ODEBUG_FREE_BATCH 4 - static void free_obj_work(struct work_struct *work) { - struct debug_obj *objs[ODEBUG_FREE_BATCH]; + struct hlist_node *tmp; + struct debug_obj *obj; unsigned long flags; - int i; + HLIST_HEAD(tofree); if (!raw_spin_trylock_irqsave(&pool_lock, flags)) return; - while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) { - for (i = 0; i < ODEBUG_FREE_BATCH; i++) { - objs[i] = hlist_entry(obj_pool.first, - typeof(*objs[0]), node); - hlist_del(&objs[i]->node); - } - obj_pool_free -= ODEBUG_FREE_BATCH; - debug_objects_freed += ODEBUG_FREE_BATCH; - /* - * We release pool_lock across kmem_cache_free() to - * avoid contention on pool_lock. - */ - raw_spin_unlock_irqrestore(&pool_lock, flags); - for (i = 0; i < ODEBUG_FREE_BATCH; i++) - kmem_cache_free(obj_cache, objs[i]); - if (!raw_spin_trylock_irqsave(&pool_lock, flags)) - return; + /* + * The objs on the pool list might be allocated before the work is + * run, so recheck if pool list it full or not, if not fill pool + * list from the global free list + */ + while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) { + obj = hlist_entry(obj_to_free.first, typeof(*obj), node); + hlist_del(&obj->node); + hlist_add_head(&obj->node, &obj_pool); + obj_pool_free++; + obj_nr_tofree--; + } + + /* + * Pool list is already full and there are still objs on the free + * list. Move remaining free objs to a temporary list to free the + * memory outside the pool_lock held region. + */ + if (obj_nr_tofree) { + hlist_move_list(&obj_to_free, &tofree); + debug_objects_freed += obj_nr_tofree; + obj_nr_tofree = 0; } raw_spin_unlock_irqrestore(&pool_lock, flags); + + hlist_for_each_entry_safe(obj, tmp, &tofree, node) { + hlist_del(&obj->node); + kmem_cache_free(obj_cache, obj); + } } -/* - * Put the object back into the pool and schedule work to free objects - * if necessary. - */ -static void free_object(struct debug_obj *obj) +static bool __free_object(struct debug_obj *obj) { unsigned long flags; - int sched = 0; + bool work; raw_spin_lock_irqsave(&pool_lock, flags); - /* - * schedule work when the pool is filled and the cache is - * initialized: - */ - if (obj_pool_free > debug_objects_pool_size && obj_cache) - sched = 1; - hlist_add_head(&obj->node, &obj_pool); - obj_pool_free++; + work = (obj_pool_free > debug_objects_pool_size) && obj_cache; obj_pool_used--; + + if (work) { + obj_nr_tofree++; + hlist_add_head(&obj->node, &obj_to_free); + } else { + obj_pool_free++; + hlist_add_head(&obj->node, &obj_pool); + } raw_spin_unlock_irqrestore(&pool_lock, flags); - if (sched) + return work; +} + +/* + * Put the object back into the pool and schedule work to free objects + * if necessary. + */ +static void free_object(struct debug_obj *obj) +{ + if (__free_object(obj)) schedule_work(&debug_obj_work); } @@ -714,13 +752,13 @@ EXPORT_SYMBOL_GPL(debug_object_active_state); static void __debug_check_no_obj_freed(const void *address, unsigned long size) { unsigned long flags, oaddr, saddr, eaddr, paddr, chunks; - struct hlist_node *tmp; - HLIST_HEAD(freelist); struct debug_obj_descr *descr; enum debug_obj_state state; struct debug_bucket *db; + struct hlist_node *tmp; struct debug_obj *obj; - int cnt; + int cnt, objs_checked = 0; + bool work = false; saddr = (unsigned long) address; eaddr = saddr + size; @@ -751,21 +789,24 @@ repeat: goto repeat; default: hlist_del(&obj->node); - hlist_add_head(&obj->node, &freelist); + work |= __free_object(obj); break; } } raw_spin_unlock_irqrestore(&db->lock, flags); - /* Now free them */ - hlist_for_each_entry_safe(obj, tmp, &freelist, node) { - hlist_del(&obj->node); - free_object(obj); - } - if (cnt > debug_objects_maxchain) debug_objects_maxchain = cnt; + + objs_checked += cnt; } + + if (objs_checked > debug_objects_maxchecked) + debug_objects_maxchecked = objs_checked; + + /* Schedule work to actually kmem_cache_free() objects */ + if (work) + schedule_work(&debug_obj_work); } void debug_check_no_obj_freed(const void *address, unsigned long size) @@ -780,12 +821,14 @@ void debug_check_no_obj_freed(const void *address, unsigned long size) static int debug_stats_show(struct seq_file *m, void *v) { seq_printf(m, "max_chain :%d\n", debug_objects_maxchain); + seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked); seq_printf(m, "warnings :%d\n", debug_objects_warnings); seq_printf(m, "fixups :%d\n", debug_objects_fixups); seq_printf(m, "pool_free :%d\n", obj_pool_free); seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free); seq_printf(m, "pool_used :%d\n", obj_pool_used); seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used); + seq_printf(m, "on_free_list :%d\n", obj_nr_tofree); seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated); seq_printf(m, "objs_freed :%d\n", debug_objects_freed); return 0; |