mutex subsystem, debugging code

PATCH In review Ingo Molnar 1 participant 1 message Dec 21, 2005

Subsystems (5)

Library code MM core Scheduler exec and binfmt +1 more subsystems

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Ingo Molnar

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2005-12-21 15:56 UTC #0 lore raw

PATCH 7/8 mutex subsystem, debugging code

mutex implementation - add debugging code.

Signed-off-by Ingo Molnar <[email protected]>

----

 include/linux/mutex-debug.h |   19 +
 include/linux/sched.h       |    5 
 kernel/fork.c               |    4 
 kernel/mutex-debug.c        |  509 ++++++++++++++++++++++++++++++++++++++++++++
 lib/Kconfig.debug           |    8 
 5 files changed, 545 insertions(+)

include/linux/mutex-debug.h new file +19 -0

Index: linux/include/linux/mutex-debug.h
===================================================================
@@ -0,0 +1,19 @@
+#ifndef __LINUX_MUTEX_DEBUG_H
+#define __LINUX_MUTEX_DEBUG_H
+
+/*
+ * Mutexes - debugging helpers:
+ */
+
+#define __DEBUG_MUTEX_INITIALIZER(lockname) \
+	, .held_list = LIST_HEAD_INIT(lockname.held_list), \
+	  .name = #lockname , .magic = &lockname
+
+#define mutex_init(sem)		__mutex_init(sem, __FUNCTION__)
+
+extern void mutex_debug_show_all_locks(void);
+extern void mutex_debug_show_held_locks(struct task_struct *filter);
+extern void mutex_debug_check_no_locks_held(struct task_struct *task);
+extern void mutex_debug_check_no_locks_freed(const void *from, const void *to);
+
+#endif

include/linux/sched.h +5 -0

Index: linux/include/linux/sched.h
===================================================================
@@ -820,6 +820,11 @@ struct task_struct {
 /* Protection of proc_dentry: nesting proc_lock, dcache_lock, write_lock_irq(&tasklist_lock); */
 	spinlock_t proc_lock;
 
+#ifdef CONFIG_DEBUG_MUTEXES
+	/* mutex deadlock detection */
+	struct mutex_waiter *blocked_on;
+#endif
+
 /* journalling filesystem info */
 	void *journal_info;

kernel/fork.c +4 -0

Index: linux/kernel/fork.c
===================================================================
@@ -973,6 +973,10 @@ static task_t *copy_process(unsigned lon
  	}
 #endif
 
+#ifdef CONFIG_DEBUG_MUTEXES
+	p->blocked_on = NULL; /* not blocked yet */
+#endif
+
 	p->tgid = p->pid;
 	if (clone_flags & CLONE_THREAD)
 		p->tgid = current->tgid;

kernel/mutex-debug.c new file +509 -0

509 lines not on this page · raw message

lib/Kconfig.debug +8 -0

Index: linux/lib/Kconfig.debug
===================================================================
@@ -95,6 +95,14 @@ config DEBUG_PREEMPT
 	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
 	  will detect preemption count underflows.
 
+config DEBUG_MUTEXES
+	bool "Mutex debugging, deadlock detection"
+	default y
+	depends on DEBUG_KERNEL
+	help
+	 This allows mutex semantics violations and mutex related deadlocks
+	 (lockups) to be detected and reported automatically.
+
 config DEBUG_SPINLOCK
 	bool "Spinlock debugging"
 	depends on DEBUG_KERNEL