[PATCH] lockdep: stacktrace subsystem, core

Framework to generate and save stacktraces quickly, without printing anything
to the console.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 50 insertions, 1 deletions

diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
new file mode 100644
index 000000000000..9cc81e572224
--- /dev/null
+++ b/include/linux/stacktrace.h
@@ -0,0 +1,20 @@
+#ifndef __LINUX_STACKTRACE_H
+#define __LINUX_STACKTRACE_H
+
+#ifdef CONFIG_STACKTRACE
+struct stack_trace {
+        unsigned int nr_entries, max_entries;
+        unsigned long *entries;
+};
+
+extern void save_stack_trace(struct stack_trace *trace,
+                             struct task_struct *task, int all_contexts,
+                             unsigned int skip);
+
+extern void print_stack_trace(struct stack_trace *trace, int spaces);
+#else
+# define save_stack_trace(trace, task, all, skip)       do { } while (0)
+# define print_stack_trace(trace)                       do { } while (0)
+#endif
+
+#endif
diff --git a/kernel/Makefile b/kernel/Makefile
index 82fb182f6f61..e7fd20e70f1b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,6 +10,7 @@ obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
             kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
             hrtimer.o
 
+obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-y += time/
 obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
 obj-$(CONFIG_FUTEX) += futex.o
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
new file mode 100644
index 000000000000..b71816e47a30
--- /dev/null
+++ b/kernel/stacktrace.c
@@ -0,0 +1,24 @@
+/*
+ * kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/sched.h>
+#include <linux/kallsyms.h>
+#include <linux/stacktrace.h>
+
+void print_stack_trace(struct stack_trace *trace, int spaces)
+{
+        int i, j;
+
+        for (i = 0; i < trace->nr_entries; i++) {
+                unsigned long ip = trace->entries[i];
+
+                for (j = 0; j < spaces + 1; j++)
+                        printk(" ");
+                print_ip_sym(ip);
+        }
+}
+
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7b3863d4f5e8..04e374c6fd46 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -107,7 +107,7 @@ config DEBUG_SLAB_LEAK
 
 config DEBUG_PREEMPT
         bool "Debug preemptible kernel"
-        depends on DEBUG_KERNEL && PREEMPT
+        depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
         default y
         help
           If you say Y here then the kernel will use a debug variant of the
@@ -149,6 +149,10 @@ config DEBUG_SPINLOCK_SLEEP
           If you say Y here, various routines which may sleep will become very
           noisy if they are called with a spinlock held.
 
+config STACKTRACE
+        bool
+        depends on STACKTRACE_SUPPORT
+
 config DEBUG_KOBJECT
         bool "kobject debugging"
         depends on DEBUG_KERNEL