* [patch 2/5] infrastructure to debug (dynamic) objects
2008-03-21 20:26 [patch 0/5] debugobject infrastructure V3 Thomas Gleixner
2008-03-21 20:26 ` [patch 1/5] slab: add a flag to prevent debug_free checks on a kmem_cache Thomas Gleixner
@ 2008-03-21 20:26 ` Thomas Gleixner
2008-03-21 20:55 ` Randy Dunlap
2008-03-24 20:04 ` Andrew Morton
2008-03-21 20:26 ` [patch 3/5] debugobjects: add documentation Thomas Gleixner
` (2 subsequent siblings)
4 siblings, 2 replies; 12+ messages in thread
From: Thomas Gleixner @ 2008-03-21 20:26 UTC (permalink / raw)
To: LKML; +Cc: Andrew Morton, Ingo Molnar, Greg KH, Randy Dunlap
[-- Attachment #1: debug-dynamic-objects.patch --]
[-- Type: text/plain, Size: 35796 bytes --]
We can see an ever repeating problem pattern with objects of any kind in
the kernel:
1) freeing of active objects
2) reinitialization of active objects
Both problems can be hard to debug because the crash happens at a
point where we have no chance to decode the root cause anymore. One
problem spot are kernel timers, where the detection of the problem
often happens in interrupt context and usually causes the machine to
panic.
While working on a timer related bug report I had to hack specialized
code into the timer subsystem to get a reasonable hint for the root
cause. This debug hack was fine for temporary use, but far from a
mergeable solution due to the intrusiveness into the timer code.
The code further lacked the ability to detect and report the root cause
instantly and keep the system operational.
Keeping the system operational is important to get hold of the debug
information without special debugging aids like serial consoles and
special knowledge of the bug reporter.
The problems described above are not restricted to timers, but timers
tend to expose it usually in a full system crash. Other objects are
less explosive, but the symptoms caused by such mistakes can be even
harder to debug.
Instead of creating specialized debugging code for the timer subsystem
a generic infrastructure is created which allows developers to verify
their code and provides an easy to enable debug facility for users in
case of trouble.
The debugobjects core code keeps track of operations on static and
dynamic objects by inserting them into a hashed list and sanity
checking them on object operations and provides additional checks
whenever kernel memory is freed.
The tracked object operations are:
- initializing an object
- adding an object to a subsystem list
- deleting an object from a subsystem list
Each operation is sanity checked before the operation is executed and
the subsystem specific code can provide a fixup function which allows
to prevent the damage of the operation. When the sanity check triggers
a warning message and a stack trace is printed.
The list of operations can be extended if the need arises. For now it's
limited to the requirements of the first user (timers).
The core code enqueues the objects into hash buckets. The hash index
is generated from the address of the object to simplify the lookup for
the check on kfree/vfree. Each bucket has it's own spinlock to avoid
contention on a global lock.
The debug code can be compiled in without being active. The runtime
overhead is minimal and could be optimized by asm alternatives. A
kernel command line option enables the debugging code.
Thanks to Ingo Molnar for review, suggestions and cleanup patches.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
Documentation/kernel-parameters.txt | 2
include/linux/debugobjects.h | 90 +++
init/main.c | 3
lib/Kconfig.debug | 23
lib/Makefile | 1
lib/debugobjects.c | 890 ++++++++++++++++++++++++++++++++++++
mm/page_alloc.c | 10
mm/slab.c | 10
mm/slub.c | 3
mm/vmalloc.c | 2
10 files changed, 1030 insertions(+), 4 deletions(-)
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -551,6 +551,8 @@ and is between 256 and 4096 characters.
1 will print _a lot_ more information - normally
only useful to kernel developers.
+ debug_objects [KNL] Enable object debugging
+
decnet.addr= [HW,NET]
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
Index: linux-2.6/include/linux/debugobjects.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/debugobjects.h
@@ -0,0 +1,90 @@
+#ifndef _LINUX_DEBUGOBJECTS_H
+#define _LINUX_DEBUGOBJECTS_H
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+
+enum debug_obj_state {
+ ODEBUG_STATE_NONE,
+ ODEBUG_STATE_INIT,
+ ODEBUG_STATE_INACTIVE,
+ ODEBUG_STATE_ACTIVE,
+ ODEBUG_STATE_DESTROYED,
+ ODEBUG_STATE_NOTAVAILABLE,
+ ODEBUG_STATE_MAX,
+};
+
+struct debug_obj_descr;
+
+/**
+ * struct debug_obj - representaion of an tracked object
+ * @node: hlist node to link the object into the tracker list
+ * @state: tracked object state
+ * @object: pointer to the real object
+ * @descr: pointer to an object type specific debug description structure
+ */
+struct debug_obj {
+ struct hlist_node node;
+ enum debug_obj_state state;
+ void *object;
+ struct debug_obj_descr *descr;
+};
+
+/**
+ * struct debug_obj_descr - object type specific debug description structure
+ * @name: name of the object typee
+ * @fixup_init: fixup function, which is called when the init check
+ * fails
+ * @fixup_activate: fixup function, which is called when the activate check
+ * fails
+ * @fixup_destroy: fixup function, which is called when the destroy check
+ * fails
+ * @fixup_free: fixup function, which is called when the free check
+ * fails
+ */
+struct debug_obj_descr {
+ const char *name;
+
+ int (*fixup_init) (void *addr, enum debug_obj_state state);
+ 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);
+};
+
+#ifdef CONFIG_DEBUG_OBJECTS
+extern void debug_object_init (void *addr, struct debug_obj_descr *descr);
+extern void
+debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr);
+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_objects_early_init(void);
+extern void debug_objects_mem_init(void);
+#else
+static inline void
+debug_object_init (void *addr, struct debug_obj_descr *descr) { }
+static inline void
+debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr) { }
+static inline void
+debug_object_activate (void *addr, struct debug_obj_descr *descr) { }
+static inline void
+debug_object_deactivate(void *addr, struct debug_obj_descr *descr) { }
+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_objects_early_init(void) { }
+static inline void debug_objects_mem_init(void) { }
+#endif
+
+#ifdef CONFIG_DEBUG_OBJECTS_FREE
+extern void debug_check_no_obj_freed(const void *address, unsigned long size);
+#else
+static inline void
+debug_check_no_obj_freed(const void *address, unsigned long size) { }
+#endif
+
+#endif
Index: linux-2.6/init/main.c
===================================================================
--- linux-2.6.orig/init/main.c
+++ linux-2.6/init/main.c
@@ -52,6 +52,7 @@
#include <linux/unwind.h>
#include <linux/buffer_head.h>
#include <linux/debug_locks.h>
+#include <linux/debugobjects.h>
#include <linux/lockdep.h>
#include <linux/pid_namespace.h>
#include <linux/device.h>
@@ -517,6 +518,7 @@ asmlinkage void __init start_kernel(void
*/
unwind_init();
lockdep_init();
+ debug_objects_early_init();
cgroup_init_early();
local_irq_disable();
@@ -610,6 +612,7 @@ asmlinkage void __init start_kernel(void
enable_debug_pagealloc();
cpu_hotplug_init();
kmem_cache_init();
+ debug_objects_mem_init();
setup_per_cpu_pageset();
numa_policy_init();
if (late_time_init)
Index: linux-2.6/lib/Kconfig.debug
===================================================================
--- linux-2.6.orig/lib/Kconfig.debug
+++ linux-2.6/lib/Kconfig.debug
@@ -183,6 +183,29 @@ config TIMER_STATS
(it defaults to deactivated on bootup and will only be activated
if some application like powertop activates it explicitly).
+config DEBUG_OBJECTS
+ bool "Debug object operations"
+ depends on DEBUG_KERNEL
+ help
+ If you say Y here, additional code will be inserted into the
+ kernel to track the life time of various objects and validate
+ the operations on those objects.
+
+config DEBUG_OBJECTS_SELFTEST
+ bool "Debug objects selftest"
+ depends on DEBUG_OBJECTS
+ help
+ This enables the selftest of the object debug code.
+
+config DEBUG_OBJECTS_FREE
+ bool "Debug objects in freed memory"
+ depends on DEBUG_OBJECTS
+ help
+ This enables checks whether a k/v free operation frees an area
+ which contains an object which has not been deactivated
+ properly. This can make kmalloc/kfree-intensive workloads
+ much slower.
+
config DEBUG_SLAB
bool "Debug slab memory allocations"
depends on DEBUG_KERNEL && SLAB
Index: linux-2.6/lib/Makefile
===================================================================
--- linux-2.6.orig/lib/Makefile
+++ linux-2.6/lib/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_LOCK_KERNEL) += kernel_lock
obj-$(CONFIG_PLIST) += plist.o
obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
obj-$(CONFIG_DEBUG_LIST) += list_debug.o
+obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
lib-y += dec_and_lock.o
Index: linux-2.6/lib/debugobjects.c
===================================================================
--- /dev/null
+++ linux-2.6/lib/debugobjects.c
@@ -0,0 +1,890 @@
+/*
+ * Generic infrastructure for lifetime debugging of objects.
+ *
+ * Started by Thomas Gleixner
+ *
+ * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
+ *
+ * For licencing details see kernel-base/COPYING
+ */
+#include <linux/debugobjects.h>
+#include <linux/interrupt.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/hash.h>
+
+#define ODEBUG_HASH_BITS 14
+#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
+
+#define ODEBUG_POOL_SIZE 512
+#define ODEBUG_POOL_MIN_LEVEL 256
+
+#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
+#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
+#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
+
+struct debug_bucket {
+ struct hlist_head list;
+ spinlock_t lock;
+};
+
+static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
+
+static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE];
+
+static DEFINE_SPINLOCK(pool_lock);
+
+static HLIST_HEAD(obj_pool);
+
+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;
+static struct kmem_cache *obj_cache;
+
+static int debug_objects_maxchain __read_mostly;
+static int debug_objects_fixups __read_mostly;
+static int debug_objects_warnings __read_mostly;
+static int debug_objects_enabled __read_mostly;
+static struct debug_obj_descr *descr_test __read_mostly;
+
+static int __init enable_object_debug(char *str)
+{
+ debug_objects_enabled = 1;
+ return 0;
+}
+early_param("debug_objects", enable_object_debug);
+
+static const char *obj_states[ODEBUG_STATE_MAX] = {
+ [ODEBUG_STATE_NONE] = "none",
+ [ODEBUG_STATE_INIT] = "initialized",
+ [ODEBUG_STATE_INACTIVE] = "inactive",
+ [ODEBUG_STATE_ACTIVE] = "active",
+ [ODEBUG_STATE_DESTROYED] = "destroyed",
+ [ODEBUG_STATE_NOTAVAILABLE] = "not available",
+};
+
+static int fill_pool(void)
+{
+ gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
+ struct debug_obj *new;
+
+ if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
+ return obj_pool_free;
+
+ if (unlikely(!obj_cache))
+ return obj_pool_free;
+
+ while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
+
+ new = kmem_cache_zalloc(obj_cache, gfp);
+ if (!new)
+ return obj_pool_free;
+
+ spin_lock(&pool_lock);
+ hlist_add_head(&new->node, &obj_pool);
+ obj_pool_free++;
+ spin_unlock(&pool_lock);
+ }
+ return obj_pool_free;
+}
+
+/*
+ * Lookup an object in the hash bucket.
+ */
+static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
+{
+ struct hlist_node *node;
+ struct debug_obj *obj;
+ int cnt = 0;
+
+ hlist_for_each_entry(obj, node, &b->list, node) {
+ cnt++;
+ if (obj->object == addr)
+ return obj;
+ }
+ if (cnt > debug_objects_maxchain)
+ debug_objects_maxchain = cnt;
+
+ return NULL;
+}
+
+/*
+ * Allocate a new object. If the pool is empty and no refill possible,
+ * switch off the debugger.
+ */
+static struct debug_obj *
+alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
+{
+ struct debug_obj *obj = NULL;
+ int retry = 0;
+
+repeat:
+ spin_lock(&pool_lock);
+ if (obj_pool.first) {
+ obj = hlist_entry(obj_pool.first, typeof(*obj), node);
+
+ obj->object = addr;
+ obj->descr = descr;
+ obj->state = ODEBUG_STATE_NONE;
+ hlist_del(&obj->node);
+
+ hlist_add_head(&obj->node, &b->list);
+
+ obj_pool_used++;
+ if (obj_pool_used > obj_pool_max_used)
+ obj_pool_max_used = obj_pool_used;
+
+ obj_pool_free--;
+ if (obj_pool_free < obj_pool_min_free)
+ obj_pool_min_free = obj_pool_free;
+ }
+ spin_unlock(&pool_lock);
+
+ if (fill_pool() && !obj && !retry++)
+ goto repeat;
+
+ return obj;
+}
+
+/*
+ * Put the object back into the pool or give it back to kmem_cache:
+ */
+static void free_object(struct debug_obj *obj)
+{
+ unsigned long idx = (unsigned long)(obj - obj_static_pool);
+
+ if (obj_pool_free < ODEBUG_POOL_SIZE || idx < ODEBUG_POOL_SIZE) {
+ spin_lock(&pool_lock);
+ hlist_add_head(&obj->node, &obj_pool);
+ obj_pool_free++;
+ obj_pool_used--;
+ spin_unlock(&pool_lock);
+ } else {
+ spin_lock(&pool_lock);
+ obj_pool_used--;
+ spin_unlock(&pool_lock);
+ kmem_cache_free(obj_cache, obj);
+ }
+}
+
+/*
+ * We run out of memory. That means we probably have tons of objects
+ * allocated.
+ */
+static void debug_objects_oom(void)
+{
+ struct debug_bucket *db = obj_hash;
+ struct hlist_node *node, *tmp;
+ struct debug_obj *obj;
+ unsigned long flags;
+ int i;
+
+ printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
+
+ for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
+ spin_lock_irqsave(&db->lock, flags);
+ hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
+ hlist_del(&obj->node);
+ free_object(obj);
+ }
+ spin_unlock_irqrestore(&db->lock, flags);
+ }
+}
+
+/*
+ * We use the pfn of the address for the hash. That way we can check
+ * for freed objects simply by checking the affected bucket.
+ */
+static struct debug_bucket *get_bucket(unsigned long addr)
+{
+ unsigned long hash;
+
+ hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
+ return &obj_hash[hash];
+}
+
+static void debug_print_object(struct debug_obj *obj, char *msg)
+{
+ static int limit;
+
+ if (limit < 5 && obj->descr != descr_test) {
+ limit++;
+ printk(KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
+ obj_states[obj->state], obj->descr->name);
+ WARN_ON(1);
+ }
+ debug_objects_warnings++;
+}
+
+/*
+ * Try to repair the damage, so we have a better chance to get useful
+ * debug output.
+ */
+static void
+debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
+ void * addr, enum debug_obj_state state)
+{
+ if (fixup)
+ debug_objects_fixups += fixup(addr, state);
+}
+
+static void debug_object_is_on_stack(void *addr, int onstack)
+{
+ void *stack = current->stack;
+ int is_on_stack;
+ static int limit;
+
+ if (limit > 4)
+ return;
+
+ is_on_stack = (addr >= stack && addr < (stack + THREAD_SIZE));
+
+ if (is_on_stack == onstack)
+ return;
+
+ limit++;
+ if (is_on_stack)
+ printk(KERN_WARNING
+ "ODEBUG: object is on stack, but not annotated\n");
+ else
+ printk(KERN_WARNING
+ "ODEBUG: object is not on stack, but annotated\n");
+ WARN_ON(1);
+}
+
+static void
+__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
+{
+ enum debug_obj_state state;
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+
+ db = get_bucket((unsigned long) addr);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (!obj) {
+ obj = alloc_object(addr, db, descr);
+ if (!obj) {
+ debug_objects_enabled = 0;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_objects_oom();
+ return;
+ }
+ debug_object_is_on_stack(addr, onstack);
+ }
+
+ switch (obj->state) {
+ case ODEBUG_STATE_NONE:
+ case ODEBUG_STATE_INIT:
+ case ODEBUG_STATE_INACTIVE:
+ obj->state = ODEBUG_STATE_INIT;
+ break;
+
+ case ODEBUG_STATE_ACTIVE:
+ debug_print_object(obj, "init");
+ state = obj->state;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_object_fixup(descr->fixup_init, addr, state);
+ return;
+
+ case ODEBUG_STATE_DESTROYED:
+ debug_print_object(obj, "init");
+ break;
+ default:
+ break;
+ }
+
+ spin_unlock_irqrestore(&db->lock, flags);
+}
+
+/**
+ * debug_object_init - debug checks when an object is initialized
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_init(void *addr, struct debug_obj_descr *descr)
+{
+ if (!debug_objects_enabled)
+ return;
+
+ __debug_object_init(addr, descr, 0);
+}
+
+/**
+ * debug_object_init_on_stack - debug checks when an object on stack is
+ * initialized
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
+{
+ if (!debug_objects_enabled)
+ return;
+
+ __debug_object_init(addr, descr, 1);
+}
+
+/**
+ * debug_object_activate - debug checks when an object is activated
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_activate(void *addr, struct debug_obj_descr *descr)
+{
+ enum debug_obj_state state;
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+
+ if (!debug_objects_enabled)
+ return;
+
+ db = get_bucket((unsigned long) addr);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (obj) {
+ switch (obj->state) {
+ case ODEBUG_STATE_INIT:
+ case ODEBUG_STATE_INACTIVE:
+ obj->state = ODEBUG_STATE_ACTIVE;
+ break;
+
+ case ODEBUG_STATE_ACTIVE:
+ debug_print_object(obj, "activate");
+ state = obj->state;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_object_fixup(descr->fixup_activate, addr, state);
+ return;
+
+ case ODEBUG_STATE_DESTROYED:
+ debug_print_object(obj, "activate");
+ break;
+ default:
+ break;
+ }
+ spin_unlock_irqrestore(&db->lock, flags);
+ return;
+ }
+
+ spin_unlock_irqrestore(&db->lock, flags);
+ /*
+ * This happens when a static object is activated. We
+ * let the type specific code decide whether this is
+ * true or not.
+ */
+ debug_object_fixup(descr->fixup_activate, addr,
+ ODEBUG_STATE_NOTAVAILABLE);
+}
+
+/**
+ * debug_object_deactivate - debug checks when an object is deactivated
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_deactivate(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);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (obj) {
+ switch (obj->state) {
+ case ODEBUG_STATE_INIT:
+ case ODEBUG_STATE_INACTIVE:
+ case ODEBUG_STATE_ACTIVE:
+ obj->state = ODEBUG_STATE_INACTIVE;
+ break;
+
+ case ODEBUG_STATE_DESTROYED:
+ debug_print_object(obj, "deactivate");
+ break;
+ default:
+ break;
+ }
+ } else {
+ struct debug_obj o = { .object = addr,
+ .state = ODEBUG_STATE_NOTAVAILABLE,
+ .descr = descr };
+
+ debug_print_object(&o, "deactivate");
+ }
+
+ spin_unlock_irqrestore(&db->lock, flags);
+}
+
+/**
+ * debug_object_destroy - debug checks when an object is destroyed
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
+{
+ enum debug_obj_state state;
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+
+ if (!debug_objects_enabled)
+ return;
+
+ db = get_bucket((unsigned long) addr);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (!obj)
+ goto out_unlock;
+
+ switch (obj->state) {
+ case ODEBUG_STATE_NONE:
+ case ODEBUG_STATE_INIT:
+ case ODEBUG_STATE_INACTIVE:
+ obj->state = ODEBUG_STATE_DESTROYED;
+ break;
+ case ODEBUG_STATE_ACTIVE:
+ debug_print_object(obj, "destroy");
+ state = obj->state;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_object_fixup(descr->fixup_destroy, addr, state);
+ return;
+
+ case ODEBUG_STATE_DESTROYED:
+ debug_print_object(obj, "destroy");
+ break;
+ default:
+ break;
+ }
+out_unlock:
+ spin_unlock_irqrestore(&db->lock, flags);
+}
+
+/**
+ * debug_object_free - debug checks when an object is freed
+ * @addr: address of the object
+ * @descr: pointer to an object specific debug description structure
+ */
+void debug_object_free(void *addr, struct debug_obj_descr *descr)
+{
+ enum debug_obj_state state;
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+
+ if (!debug_objects_enabled)
+ return;
+
+ db = get_bucket((unsigned long) addr);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (!obj)
+ goto out_unlock;
+
+ switch (obj->state) {
+ case ODEBUG_STATE_ACTIVE:
+ debug_print_object(obj, "free");
+ state = obj->state;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_object_fixup(descr->fixup_free, addr, state);
+ return;
+ default:
+ hlist_del(&obj->node);
+ free_object(obj);
+ break;
+ }
+out_unlock:
+ spin_unlock_irqrestore(&db->lock, flags);
+}
+
+#ifdef CONFIG_DEBUG_OBJECTS_FREE
+static void __debug_check_no_obj_freed(const void *address, unsigned long size)
+{
+ unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
+ struct hlist_node *node, *tmp;
+ struct debug_obj_descr *descr;
+ enum debug_obj_state state;
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ int cnt;
+
+ saddr = (unsigned long) address;
+ eaddr = saddr + size;
+ paddr = saddr & ODEBUG_CHUNK_MASK;
+ chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
+ chunks >>= ODEBUG_CHUNK_SHIFT;
+
+ for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
+ db = get_bucket(paddr);
+
+repeat:
+ cnt = 0;
+ spin_lock_irqsave(&db->lock, flags);
+ hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
+ cnt++;
+ oaddr = (unsigned long) obj->object;
+ if (oaddr < saddr || oaddr >= eaddr)
+ continue;
+
+ switch (obj->state) {
+ case ODEBUG_STATE_ACTIVE:
+ debug_print_object(obj, "free");
+ descr = obj->descr;
+ state = obj->state;
+ spin_unlock_irqrestore(&db->lock, flags);
+ debug_object_fixup(descr->fixup_free,
+ (void *) oaddr, state);
+ goto repeat;
+ default:
+ hlist_del(&obj->node);
+ free_object(obj);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&db->lock, flags);
+ if (cnt > debug_objects_maxchain)
+ debug_objects_maxchain = cnt;
+ }
+}
+
+void debug_check_no_obj_freed(const void *address, unsigned long size)
+{
+ if (debug_objects_enabled)
+ __debug_check_no_obj_freed(address, size);
+}
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+
+static int debug_stats_show(struct seq_file *m, void *v)
+{
+ seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
+ 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);
+ return 0;
+}
+
+static int debug_stats_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, debug_stats_show, NULL);
+}
+
+static const struct file_operations debug_stats_fops = {
+ .open = debug_stats_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int __init debug_objects_init_debugfs(void)
+{
+ struct dentry *dbgdir, *dbgstats;
+
+ if (!debug_objects_enabled)
+ return 0;
+
+ dbgdir = debugfs_create_dir("debug_objects", NULL);
+ if (!dbgdir)
+ return -ENOMEM;
+
+ dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
+ &debug_stats_fops);
+ if (!dbgstats)
+ goto err;
+
+ return 0;
+
+err:
+ debugfs_remove(dbgdir);
+
+ return -ENOMEM;
+}
+__initcall(debug_objects_init_debugfs);
+
+#else
+static inline void debug_objects_init_debugfs(void) { }
+#endif
+
+#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
+
+/* Random data structure for the self test */
+struct self_test {
+ unsigned long dummy1[6];
+ int static_init;
+ unsigned long dummy2[3];
+};
+
+static __initdata struct debug_obj_descr descr_type_test;
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static int __init fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct self_test *obj = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ debug_object_deactivate(obj, &descr_type_test);
+ debug_object_init(obj, &descr_type_test);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown object is activated (might be a statically initialized object)
+ */
+static int __init fixup_activate(void *addr, enum debug_obj_state state)
+{
+ struct self_test *obj = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_NOTAVAILABLE:
+ if (obj->static_init == 1) {
+ debug_object_init(obj, &descr_type_test);
+ debug_object_activate(obj, &descr_type_test);
+ /*
+ * Real code should return 0 here ! This is
+ * not a fixup of some bad behaviour. We
+ * merily call the debug_init function to keep
+ * track of the object.
+ */
+ return 1;
+ } else {
+ /* Real code needs to emit a warning here */
+ }
+ return 0;
+
+ case ODEBUG_STATE_ACTIVE:
+ debug_object_deactivate(obj, &descr_type_test);
+ debug_object_activate(obj, &descr_type_test);
+ return 1;
+
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_destroy is called when:
+ * - an active object is destroyed
+ */
+static int __init fixup_destroy(void *addr, enum debug_obj_state state)
+{
+ struct self_test *obj = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ debug_object_deactivate(obj, &descr_type_test);
+ debug_object_destroy(obj, &descr_type_test);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static int __init fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct self_test *obj = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ debug_object_deactivate(obj, &descr_type_test);
+ debug_object_free(obj, &descr_type_test);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static int
+check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
+{
+ struct debug_bucket *db;
+ struct debug_obj *obj;
+ unsigned long flags;
+ int res = -EINVAL;
+
+ db = get_bucket((unsigned long) addr);
+
+ spin_lock_irqsave(&db->lock, flags);
+
+ obj = lookup_object(addr, db);
+ if (!obj && state != ODEBUG_STATE_NONE) {
+ printk(KERN_ERR "ODEBUG: selftest object not found\n");
+ WARN_ON(1);
+ goto out;
+ }
+ if (obj && obj->state != state) {
+ printk(KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
+ obj->state, state);
+ WARN_ON(1);
+ goto out;
+ }
+ if (fixups != debug_objects_fixups) {
+ printk(KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
+ fixups, debug_objects_fixups);
+ WARN_ON(1);
+ goto out;
+ }
+ if (warnings != debug_objects_warnings) {
+ printk(KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
+ warnings, debug_objects_warnings);
+ WARN_ON(1);
+ goto out;
+ }
+ res = 0;
+out:
+ spin_unlock_irqrestore(&db->lock, flags);
+ if (res)
+ debug_objects_enabled = 0;
+ return res;
+}
+
+static __initdata struct debug_obj_descr descr_type_test = {
+ .name = "selftest",
+ .fixup_init = fixup_init,
+ .fixup_activate = fixup_activate,
+ .fixup_destroy = fixup_destroy,
+ .fixup_free = fixup_free,
+};
+
+static __initdata struct self_test obj = { .static_init = 0 };
+
+static void __init debug_objects_selftest(void)
+{
+ int fixups, oldfixups, warnings, oldwarnings;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ fixups = oldfixups = debug_objects_fixups;
+ warnings = oldwarnings = debug_objects_warnings;
+ descr_test = &descr_type_test;
+
+ debug_object_init(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
+ goto out;
+ debug_object_activate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
+ goto out;
+ debug_object_activate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
+ goto out;
+ debug_object_deactivate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
+ goto out;
+ debug_object_destroy(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
+ goto out;
+ debug_object_init(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
+ goto out;
+ debug_object_activate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
+ goto out;
+ debug_object_deactivate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
+ goto out;
+ debug_object_free(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
+ goto out;
+
+ obj.static_init = 1;
+ debug_object_activate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, warnings))
+ goto out;
+ debug_object_init(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
+ goto out;
+ debug_object_free(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
+ goto out;
+
+#ifdef CONFIG_DEBUG_OBJECTS_FREE
+ debug_object_init(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
+ goto out;
+ debug_object_activate(&obj, &descr_type_test);
+ if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
+ goto out;
+ __debug_check_no_obj_freed(&obj, sizeof(obj));
+ if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
+ goto out;
+#endif
+ printk(KERN_INFO "ODEBUG: selftest passed\n");
+
+out:
+ debug_objects_fixups = oldfixups;
+ debug_objects_warnings = oldwarnings;
+ descr_test = NULL;
+
+ local_irq_restore(flags);
+}
+#else
+static inline void debug_objects_selftest(void) { }
+#endif
+
+/*
+ * Called during early boot to initialize the hash buckets and link
+ * the static object pool objects into the poll list. After this call
+ * the object tracker is fully operational.
+ */
+void __init debug_objects_early_init(void)
+{
+ int i;
+
+ for (i = 0; i < ODEBUG_HASH_SIZE; i++)
+ spin_lock_init(&obj_hash[i].lock);
+
+ for (i = 0; i < ODEBUG_POOL_SIZE; i++)
+ hlist_add_head(&obj_static_pool[i].node, &obj_pool);
+}
+
+/*
+ * Called after the kmem_caches are functional to setup a dedicated
+ * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
+ * prevents that the debug code is called on kmem_cache_free() for the
+ * debug tracker objects to avoid recursive calls.
+ */
+void __init debug_objects_mem_init(void)
+{
+ if (!debug_objects_enabled)
+ return;
+
+ obj_cache = kmem_cache_create("debug_objects_cache",
+ sizeof (struct debug_obj), 0,
+ SLAB_DEBUG_OBJECTS, NULL);
+
+ if (!obj_cache)
+ debug_objects_enabled = 0;
+ else
+ debug_objects_selftest();
+}
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -45,6 +45,7 @@
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
#include <linux/memcontrol.h>
+#include <linux/debugobjects.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -532,8 +533,11 @@ static void __free_pages_ok(struct page
if (reserved)
return;
- if (!PageHighMem(page))
+ if (!PageHighMem(page)) {
debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
+ debug_check_no_obj_freed(page_address(page),
+ PAGE_SIZE << order);
+ }
arch_free_page(page, order);
kernel_map_pages(page, 1 << order, 0);
@@ -995,8 +999,10 @@ static void free_hot_cold_page(struct pa
if (free_pages_check(page))
return;
- if (!PageHighMem(page))
+ if (!PageHighMem(page)) {
debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
+ debug_check_no_obj_freed(page_address(page), PAGE_SIZE);
+ }
arch_free_page(page, 0);
kernel_map_pages(page, 1, 0);
Index: linux-2.6/mm/slab.c
===================================================================
--- linux-2.6.orig/mm/slab.c
+++ linux-2.6/mm/slab.c
@@ -110,6 +110,7 @@
#include <linux/fault-inject.h>
#include <linux/rtmutex.h>
#include <linux/reciprocal_div.h>
+#include <linux/debugobjects.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
@@ -178,12 +179,14 @@
SLAB_CACHE_DMA | \
SLAB_STORE_USER | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
- SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
+ SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
+ SLAB_DEBUG_OBJECTS)
#else
# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
SLAB_CACHE_DMA | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
- SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
+ SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
+ SLAB_DEBUG_OBJECTS)
#endif
/*
@@ -3764,6 +3767,8 @@ void kmem_cache_free(struct kmem_cache *
local_irq_save(flags);
debug_check_no_locks_freed(objp, obj_size(cachep));
+ if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
+ debug_check_no_obj_freed(objp, obj_size(cachep));
__cache_free(cachep, objp);
local_irq_restore(flags);
}
@@ -3789,6 +3794,7 @@ void kfree(const void *objp)
kfree_debugcheck(objp);
c = virt_to_cache(objp);
debug_check_no_locks_freed(objp, obj_size(c));
+ debug_check_no_obj_freed(objp, obj_size(c));
__cache_free(c, (void *)objp);
local_irq_restore(flags);
}
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c
+++ linux-2.6/mm/slub.c
@@ -21,6 +21,7 @@
#include <linux/ctype.h>
#include <linux/kallsyms.h>
#include <linux/memory.h>
+#include <linux/debugobjects.h>
/*
* Lock order:
@@ -1694,6 +1695,8 @@ static __always_inline void slab_free(st
local_irq_save(flags);
c = get_cpu_slab(s, smp_processor_id());
debug_check_no_locks_freed(object, c->objsize);
+ if (!(s->flags & SLAB_DEBUG_OBJECTS))
+ debug_check_no_obj_freed(object, s->objsize);
if (likely(page == c->page && c->node >= 0)) {
object[c->offset] = c->freelist;
c->freelist = object;
Index: linux-2.6/mm/vmalloc.c
===================================================================
--- linux-2.6.orig/mm/vmalloc.c
+++ linux-2.6/mm/vmalloc.c
@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
+#include <linux/debugobjects.h>
#include <linux/vmalloc.h>
@@ -383,6 +384,7 @@ static void __vunmap(const void *addr, i
}
debug_check_no_locks_freed(addr, area->size);
+ debug_check_no_obj_freed(addr, area->size);
if (deallocate_pages) {
int i;
--
^ permalink raw reply [flat|nested] 12+ messages in thread* [patch 4/5] debugobjects: add timer specific object debugging code
2008-03-21 20:26 [patch 0/5] debugobject infrastructure V3 Thomas Gleixner
` (2 preceding siblings ...)
2008-03-21 20:26 ` [patch 3/5] debugobjects: add documentation Thomas Gleixner
@ 2008-03-21 20:26 ` Thomas Gleixner
2008-04-26 16:28 ` Andrew Morton
2008-03-21 20:26 ` [patch 5/5] add hrtimer specific debugobjects code Thomas Gleixner
4 siblings, 1 reply; 12+ messages in thread
From: Thomas Gleixner @ 2008-03-21 20:26 UTC (permalink / raw)
To: LKML; +Cc: Andrew Morton, Ingo Molnar, Greg KH, Randy Dunlap
[-- Attachment #1: timer-debugging.patch --]
[-- Type: text/plain, Size: 10132 bytes --]
Add calls to the generic object debugging infrastructure and provide
fixup functions which allow to keep the system alive when recoverable
problems have been detected by the object debugging core code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
---
drivers/parport/ieee1284.c | 4 -
fs/aio.c | 5 -
include/linux/poison.h | 7 ++
include/linux/timer.h | 23 ++++++
kernel/timer.c | 153 ++++++++++++++++++++++++++++++++++++++++++---
lib/Kconfig.debug | 8 ++
6 files changed, 187 insertions(+), 13 deletions(-)
Index: linux-2.6/drivers/parport/ieee1284.c
===================================================================
--- linux-2.6.orig/drivers/parport/ieee1284.c
+++ linux-2.6/drivers/parport/ieee1284.c
@@ -76,7 +76,7 @@ int parport_wait_event (struct parport *
semaphore. */
return 1;
- init_timer (&timer);
+ init_timer_on_stack(&timer);
timer.expires = jiffies + timeout;
timer.function = timeout_waiting_on_port;
port_from_cookie[port->number % PARPORT_MAX] = port;
@@ -88,6 +88,8 @@ int parport_wait_event (struct parport *
/* Timed out. */
ret = 1;
+ destroy_timer_on_stack(&timer);
+
return ret;
}
Index: linux-2.6/fs/aio.c
===================================================================
--- linux-2.6.orig/fs/aio.c
+++ linux-2.6/fs/aio.c
@@ -1069,9 +1069,7 @@ static void timeout_func(unsigned long d
static inline void init_timeout(struct aio_timeout *to)
{
- init_timer(&to->timer);
- to->timer.data = (unsigned long)to;
- to->timer.function = timeout_func;
+ setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
to->timed_out = 0;
to->p = current;
}
@@ -1201,6 +1199,7 @@ retry:
if (timeout)
clear_timeout(&to);
out:
+ destroy_timer_on_stack(&to.timer);
return i ? i : ret;
}
Index: linux-2.6/include/linux/poison.h
===================================================================
--- linux-2.6.orig/include/linux/poison.h
+++ linux-2.6/include/linux/poison.h
@@ -10,6 +10,13 @@
#define LIST_POISON1 ((void *) 0x00100100)
#define LIST_POISON2 ((void *) 0x00200200)
+/********** include/linux/timer.h **********/
+/*
+ * Magic number "tsta" to indicate a static timer initializer
+ * for the object debugging code.
+ */
+#define TIMER_ENTRY_STATIC ((void *) 0x74737461)
+
/********** mm/slab.c **********/
/*
* Magic nums for obj red zoning.
Index: linux-2.6/include/linux/timer.h
===================================================================
--- linux-2.6.orig/include/linux/timer.h
+++ linux-2.6/include/linux/timer.h
@@ -4,6 +4,7 @@
#include <linux/list.h>
#include <linux/ktime.h>
#include <linux/stddef.h>
+#include <linux/debugobjects.h>
struct tvec_base;
@@ -25,6 +26,7 @@ struct timer_list {
extern struct tvec_base boot_tvec_bases;
#define TIMER_INITIALIZER(_function, _expires, _data) { \
+ .entry = { .prev = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
@@ -38,6 +40,17 @@ extern struct tvec_base boot_tvec_bases;
void init_timer(struct timer_list *timer);
void init_timer_deferrable(struct timer_list *timer);
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+extern void init_timer_on_stack(struct timer_list *timer);
+extern void destroy_timer_on_stack(struct timer_list *timer);
+#else
+static inline void destroy_timer_on_stack(struct timer_list *timer) { }
+static inline void init_timer_on_stack(struct timer_list *timer)
+{
+ init_timer(timer);
+}
+#endif
+
static inline void setup_timer(struct timer_list * timer,
void (*function)(unsigned long),
unsigned long data)
@@ -47,6 +60,15 @@ static inline void setup_timer(struct ti
init_timer(timer);
}
+static inline void setup_timer_on_stack(struct timer_list *timer,
+ void (*function)(unsigned long),
+ unsigned long data)
+{
+ timer->function = function;
+ timer->data = data;
+ init_timer_on_stack(timer);
+}
+
/**
* timer_pending - is a timer pending?
* @timer: the timer in question
@@ -164,5 +186,4 @@ unsigned long __round_jiffies_relative(u
unsigned long round_jiffies(unsigned long j);
unsigned long round_jiffies_relative(unsigned long j);
-
#endif
Index: linux-2.6/kernel/timer.c
===================================================================
--- linux-2.6.orig/kernel/timer.c
+++ linux-2.6/kernel/timer.c
@@ -320,14 +320,130 @@ static void timer_stats_account_timer(st
static void timer_stats_account_timer(struct timer_list *timer) {}
#endif
-/**
- * init_timer - initialize a timer.
- * @timer: the timer to be initialized
- *
- * init_timer() must be done to a timer prior calling *any* of the
- * other timer functions.
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static struct debug_obj_descr timer_debug_descr;
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
*/
-void init_timer(struct timer_list *timer)
+static int timer_fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_init(timer, &timer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown object is activated (might be a statically initialized object)
+ */
+static int timer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+
+ case ODEBUG_STATE_NOTAVAILABLE:
+ /*
+ * This is not really a fixup. The timer was
+ * statically initialized. We just make sure that it
+ * is tracked in the object tracker.
+ */
+ if (timer->entry.next == NULL &&
+ timer->entry.prev == TIMER_ENTRY_STATIC) {
+ debug_object_init(timer, &timer_debug_descr);
+ debug_object_activate(timer, &timer_debug_descr);
+ return 0;
+ } else {
+ WARN_ON_ONCE(1);
+ }
+ return 0;
+
+ case ODEBUG_STATE_ACTIVE:
+ WARN_ON(1);
+
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static int timer_fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_free(timer, &timer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static struct debug_obj_descr timer_debug_descr = {
+ .name = "timer_list",
+ .fixup_init = timer_fixup_init,
+ .fixup_activate = timer_fixup_activate,
+ .fixup_free = timer_fixup_free,
+};
+
+static inline void debug_timer_init(struct timer_list *timer)
+{
+ debug_object_init(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_activate(struct timer_list *timer)
+{
+ debug_object_activate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_deactivate(struct timer_list *timer)
+{
+ debug_object_deactivate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_free(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+
+static void __init_timer(struct timer_list *timer);
+
+void init_timer_on_stack(struct timer_list *timer)
+{
+ debug_object_init_on_stack(timer, &timer_debug_descr);
+ __init_timer(timer);
+}
+EXPORT_SYMBOL_GPL(init_timer_on_stack);
+
+void destroy_timer_on_stack(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
+
+#else
+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) { }
+#endif
+
+static void __init_timer(struct timer_list *timer)
{
timer->entry.next = NULL;
timer->base = __raw_get_cpu_var(tvec_bases);
@@ -337,6 +453,19 @@ void init_timer(struct timer_list *timer
memset(timer->start_comm, 0, TASK_COMM_LEN);
#endif
}
+
+/**
+ * init_timer - initialize a timer.
+ * @timer: the timer to be initialized
+ *
+ * init_timer() must be done to a timer prior calling *any* of the
+ * other timer functions.
+ */
+void init_timer(struct timer_list *timer)
+{
+ debug_timer_init(timer);
+ __init_timer(timer);
+}
EXPORT_SYMBOL(init_timer);
void init_timer_deferrable(struct timer_list *timer)
@@ -351,6 +480,8 @@ static inline void detach_timer(struct t
{
struct list_head *entry = &timer->entry;
+ debug_timer_deactivate(timer);
+
__list_del(entry->prev, entry->next);
if (clear_pending)
entry->next = NULL;
@@ -405,6 +536,8 @@ int __mod_timer(struct timer_list *timer
ret = 1;
}
+ debug_timer_activate(timer);
+
new_base = __get_cpu_var(tvec_bases);
if (base != new_base) {
@@ -450,6 +583,7 @@ void add_timer_on(struct timer_list *tim
BUG_ON(timer_pending(timer) || !timer->function);
spin_lock_irqsave(&base->lock, flags);
timer_set_base(timer, base);
+ debug_timer_activate(timer);
internal_add_timer(base, timer);
spin_unlock_irqrestore(&base->lock, flags);
}
@@ -1078,11 +1212,14 @@ signed long __sched schedule_timeout(sig
expire = timeout + jiffies;
- setup_timer(&timer, process_timeout, (unsigned long)current);
+ setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
__mod_timer(&timer, expire);
schedule();
del_singleshot_timer_sync(&timer);
+ /* Remove the timer from the object tracker */
+ destroy_timer_on_stack(&timer);
+
timeout = expire - jiffies;
out:
Index: linux-2.6/lib/Kconfig.debug
===================================================================
--- linux-2.6.orig/lib/Kconfig.debug
+++ linux-2.6/lib/Kconfig.debug
@@ -206,6 +206,14 @@ config DEBUG_OBJECTS_FREE
properly. This can make kmalloc/kfree-intensive workloads
much slower.
+config DEBUG_OBJECTS_TIMERS
+ bool "Debug timer objects"
+ depends on DEBUG_OBJECTS
+ help
+ If you say Y here, additional code will be inserted into the
+ timer routines to track the life time of timer objects and
+ validate the timer operations.
+
config DEBUG_SLAB
bool "Debug slab memory allocations"
depends on DEBUG_KERNEL && SLAB
--
^ permalink raw reply [flat|nested] 12+ messages in thread* [patch 5/5] add hrtimer specific debugobjects code
2008-03-21 20:26 [patch 0/5] debugobject infrastructure V3 Thomas Gleixner
` (3 preceding siblings ...)
2008-03-21 20:26 ` [patch 4/5] debugobjects: add timer specific object debugging code Thomas Gleixner
@ 2008-03-21 20:26 ` Thomas Gleixner
4 siblings, 0 replies; 12+ messages in thread
From: Thomas Gleixner @ 2008-03-21 20:26 UTC (permalink / raw)
To: LKML; +Cc: Andrew Morton, Ingo Molnar, Greg KH, Randy Dunlap
[-- Attachment #1: hrtimer-debugging.patch --]
[-- Type: text/plain, Size: 11331 bytes --]
hrtimers have now dynamic users in the network code. Put them under
debugobjects surveillance as well.
Add calls to the generic object debugging infrastructure and provide
fixup functions which allow to keep the system alive when recoverable
problems have been detected by the object debugging core code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/hrtimer.h | 15 ++++
kernel/futex.c | 13 +++
kernel/hrtimer.c | 176 ++++++++++++++++++++++++++++++++++++++++++------
3 files changed, 182 insertions(+), 22 deletions(-)
Index: linux-2.6/include/linux/hrtimer.h
===================================================================
--- linux-2.6.orig/include/linux/hrtimer.h
+++ linux-2.6/include/linux/hrtimer.h
@@ -268,6 +268,21 @@ extern ktime_t ktime_get_real(void);
extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
enum hrtimer_mode mode);
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
+ enum hrtimer_mode mode);
+
+extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
+#else
+static inline void hrtimer_init_on_stack(struct hrtimer *timer,
+ clockid_t which_clock,
+ enum hrtimer_mode mode)
+{
+ hrtimer_init(timer, which_clock, mode);
+}
+static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
+#endif
+
/* Basic timer operations: */
extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
const enum hrtimer_mode mode);
Index: linux-2.6/kernel/futex.c
===================================================================
--- linux-2.6.orig/kernel/futex.c
+++ linux-2.6/kernel/futex.c
@@ -1266,7 +1266,7 @@ static int futex_wait(u32 __user *uaddr,
if (!abs_time)
schedule();
else {
- hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
t.timer.expires = *abs_time;
@@ -1286,6 +1286,8 @@ static int futex_wait(u32 __user *uaddr,
/* Flag if a timeout occured */
rem = (t.task == NULL);
+
+ destroy_hrtimer_on_stack(&t.timer);
}
}
__set_current_state(TASK_RUNNING);
@@ -1367,7 +1369,8 @@ static int futex_lock_pi(u32 __user *uad
if (time) {
to = &timeout;
- hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+ hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME,
+ HRTIMER_MODE_ABS);
hrtimer_init_sleeper(to, current);
to->timer.expires = *time;
}
@@ -1581,6 +1584,8 @@ static int futex_lock_pi(u32 __user *uad
unqueue_me_pi(&q);
futex_unlock_mm(fshared);
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret != -EINTR ? ret : -ERESTARTNOINTR;
out_unlock_release_sem:
@@ -1588,6 +1593,8 @@ static int futex_lock_pi(u32 __user *uad
out_release_sem:
futex_unlock_mm(fshared);
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret;
uaddr_faulted:
@@ -1615,6 +1622,8 @@ static int futex_lock_pi(u32 __user *uad
if (!ret && (uval != -EFAULT))
goto retry;
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret;
}
Index: linux-2.6/kernel/hrtimer.c
===================================================================
--- linux-2.6.orig/kernel/hrtimer.c
+++ linux-2.6/kernel/hrtimer.c
@@ -43,6 +43,7 @@
#include <linux/tick.h>
#include <linux/seq_file.h>
#include <linux/err.h>
+#include <linux/debugobjects.h>
#include <asm/uaccess.h>
@@ -342,6 +343,115 @@ ktime_t ktime_add_safe(const ktime_t lhs
return res;
}
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static struct debug_obj_descr hrtimer_debug_descr;
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct hrtimer *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ hrtimer_cancel(timer);
+ debug_object_init(timer, &hrtimer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown object is activated (might be a statically initialized object)
+ */
+static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+ switch (state) {
+
+ case ODEBUG_STATE_NOTAVAILABLE:
+ WARN_ON_ONCE(1);
+ return 0;
+
+ case ODEBUG_STATE_ACTIVE:
+ WARN_ON(1);
+
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct hrtimer *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ hrtimer_cancel(timer);
+ debug_object_free(timer, &hrtimer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static struct debug_obj_descr hrtimer_debug_descr = {
+ .name = "hrtimer",
+ .fixup_init = hrtimer_fixup_init,
+ .fixup_activate = hrtimer_fixup_activate,
+ .fixup_free = hrtimer_fixup_free,
+};
+
+static inline void debug_hrtimer_init(struct hrtimer *timer)
+{
+ debug_object_init(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_activate(struct hrtimer *timer)
+{
+ debug_object_activate(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
+{
+ debug_object_deactivate(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_free(struct hrtimer *timer)
+{
+ debug_object_free(timer, &hrtimer_debug_descr);
+}
+
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode);
+
+void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
+{
+ debug_object_init_on_stack(timer, &hrtimer_debug_descr);
+ __hrtimer_init(timer, clock_id, mode);
+}
+
+void destroy_hrtimer_on_stack(struct hrtimer *timer)
+{
+ debug_object_free(timer, &hrtimer_debug_descr);
+}
+
+#else
+static inline void debug_hrtimer_init(struct hrtimer *timer) { }
+static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
+#endif
+
/*
* Check, whether the timer is on the callback pending list
*/
@@ -567,6 +677,7 @@ static inline int hrtimer_enqueue_reprog
/* Timer is expired, act upon the callback mode */
switch(timer->cb_mode) {
case HRTIMER_CB_IRQSAFE_NO_RESTART:
+ debug_hrtimer_deactivate(timer);
/*
* We can call the callback from here. No restart
* happens, so no danger of recursion
@@ -581,6 +692,7 @@ static inline int hrtimer_enqueue_reprog
* the tick timer in the softirq ! The calling site
* takes care of this.
*/
+ debug_hrtimer_deactivate(timer);
return 1;
case HRTIMER_CB_IRQSAFE:
case HRTIMER_CB_SOFTIRQ:
@@ -730,6 +842,8 @@ static void enqueue_hrtimer(struct hrtim
struct hrtimer *entry;
int leftmost = 1;
+ debug_hrtimer_activate(timer);
+
/*
* Find the right place in the rbtree:
*/
@@ -826,6 +940,7 @@ remove_hrtimer(struct hrtimer *timer, st
* reprogramming happens in the interrupt handler. This is a
* rare case and less expensive than a smp call.
*/
+ debug_hrtimer_deactivate(timer);
timer_stats_hrtimer_clear_start_info(timer);
reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
@@ -873,6 +988,7 @@ hrtimer_start(struct hrtimer *timer, kti
tim = ktime_add_safe(tim, base->resolution);
#endif
}
+
timer->expires = tim;
timer_stats_hrtimer_set_start_info(timer);
@@ -996,14 +1112,8 @@ ktime_t hrtimer_get_next_event(void)
}
#endif
-/**
- * hrtimer_init - initialize a timer to the given clock
- * @timer: the timer to be initialized
- * @clock_id: the clock to be used
- * @mode: timer mode abs/rel
- */
-void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
- enum hrtimer_mode mode)
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
{
struct hrtimer_cpu_base *cpu_base;
@@ -1024,6 +1134,19 @@ void hrtimer_init(struct hrtimer *timer,
memset(timer->start_comm, 0, TASK_COMM_LEN);
#endif
}
+
+/**
+ * hrtimer_init - initialize a timer to the given clock
+ * @timer: the timer to be initialized
+ * @clock_id: the clock to be used
+ * @mode: timer mode abs/rel
+ */
+void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
+{
+ debug_hrtimer_init(timer);
+ __hrtimer_init(timer, clock_id, mode);
+}
EXPORT_SYMBOL_GPL(hrtimer_init);
/**
@@ -1057,6 +1180,7 @@ static void run_hrtimer_pending(struct h
timer = list_entry(cpu_base->cb_pending.next,
struct hrtimer, cb_entry);
+ debug_hrtimer_deactivate(timer);
timer_stats_account_hrtimer(timer);
fn = timer->function;
@@ -1094,6 +1218,7 @@ static void __run_hrtimer(struct hrtimer
enum hrtimer_restart (*fn)(struct hrtimer *);
int restart;
+ debug_hrtimer_deactivate(timer);
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
timer_stats_account_hrtimer(timer);
@@ -1353,22 +1478,26 @@ long __sched hrtimer_nanosleep_restart(s
{
struct hrtimer_sleeper t;
struct timespec __user *rmtp;
+ int ret = 0;
- hrtimer_init(&t.timer, restart->arg0, HRTIMER_MODE_ABS);
+ hrtimer_init_on_stack(&t.timer, restart->arg0, HRTIMER_MODE_ABS);
t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
- return 0;
+ goto out;
rmtp = (struct timespec __user *)restart->arg1;
if (rmtp) {
- int ret = update_rmtp(&t.timer, rmtp);
+ ret = update_rmtp(&t.timer, rmtp);
if (ret <= 0)
- return ret;
+ goto out;
}
/* The other values in restart are already filled in */
- return -ERESTART_RESTARTBLOCK;
+ ret = -ERESTART_RESTARTBLOCK;
+out:
+ destroy_hrtimer_on_stack(&t.timer);
+ return ret;
}
long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
@@ -1376,20 +1505,23 @@ long hrtimer_nanosleep(struct timespec *
{
struct restart_block *restart;
struct hrtimer_sleeper t;
+ int ret = 0;
- hrtimer_init(&t.timer, clockid, mode);
+ hrtimer_init_on_stack(&t.timer, clockid, mode);
t.timer.expires = timespec_to_ktime(*rqtp);
if (do_nanosleep(&t, mode))
- return 0;
+ goto out;
/* Absolute timers do not update the rmtp value and restart: */
- if (mode == HRTIMER_MODE_ABS)
- return -ERESTARTNOHAND;
+ if (mode == HRTIMER_MODE_ABS) {
+ ret = -ERESTARTNOHAND;
+ goto out;
+ }
if (rmtp) {
- int ret = update_rmtp(&t.timer, rmtp);
+ ret = update_rmtp(&t.timer, rmtp);
if (ret <= 0)
- return ret;
+ goto out;
}
restart = ¤t_thread_info()->restart_block;
@@ -1399,7 +1531,10 @@ long hrtimer_nanosleep(struct timespec *
restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF;
restart->arg3 = t.timer.expires.tv64 >> 32;
- return -ERESTART_RESTARTBLOCK;
+ ret = -ERESTART_RESTARTBLOCK;
+out:
+ destroy_hrtimer_on_stack(&t.timer);
+ return ret;
}
asmlinkage long
@@ -1445,6 +1580,7 @@ static void migrate_hrtimer_list(struct
while ((node = rb_first(&old_base->active))) {
timer = rb_entry(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
+ debug_hrtimer_deactivate(timer);
__remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
timer->base = new_base;
/*
--
^ permalink raw reply [flat|nested] 12+ messages in thread