Merge branch 'core/stacktrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core/stacktrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  generic-ipi: powerpc/generic-ipi tree build failure
  stacktrace: fix build failure on sparc64
  stacktrace: export save_stack_trace[_tsk]
  stacktrace: fix modular build, export print_stack_trace and save_stack_trace
  backtrace: replace timer with tasklet + completions
  stacktrace: add saved stack traces to backtrace self-test
  stacktrace: print_stack_trace() cleanup
  debugging: make stacktrace independent from DEBUG_KERNEL
  stacktrace: don't crash on invalid stack trace structs

2 files changed, 62 insertions, 17 deletions

diff --git a/kernel/backtracetest.c b/kernel/backtracetest.c
index d1a7605c5b8f..a5e026bc45c4 100644
--- a/kernel/backtracetest.c
+++ b/kernel/backtracetest.c
@@ -10,30 +10,73 @@
  * of the License.
  */
 
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/sched.h>
-#include <linux/delay.h>
+#include <linux/stacktrace.h>
+
+static void backtrace_test_normal(void)
+{
+        printk("Testing a backtrace from process context.\n");
+        printk("The following trace is a kernel self test and not a bug!\n");
 
-static struct timer_list backtrace_timer;
+        dump_stack();
+}
 
-static void backtrace_test_timer(unsigned long data)
+static DECLARE_COMPLETION(backtrace_work);
+
+static void backtrace_test_irq_callback(unsigned long data)
+{
+        dump_stack();
+        complete(&backtrace_work);
+}
+
+static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0);
+
+static void backtrace_test_irq(void)
 {
         printk("Testing a backtrace from irq context.\n");
         printk("The following trace is a kernel self test and not a bug!\n");
-        dump_stack();
+
+        init_completion(&backtrace_work);
+        tasklet_schedule(&backtrace_tasklet);
+        wait_for_completion(&backtrace_work);
+}
+
+#ifdef CONFIG_STACKTRACE
+static void backtrace_test_saved(void)
+{
+        struct stack_trace trace;
+        unsigned long entries[8];
+
+        printk("Testing a saved backtrace.\n");
+        printk("The following trace is a kernel self test and not a bug!\n");
+
+        trace.nr_entries = 0;
+        trace.max_entries = ARRAY_SIZE(entries);
+        trace.entries = entries;
+        trace.skip = 0;
+
+        save_stack_trace(&trace);
+        print_stack_trace(&trace, 0);
+}
+#else
+static void backtrace_test_saved(void)
+{
+        printk("Saved backtrace test skipped.\n");
 }
+#endif
+
 static int backtrace_regression_test(void)
 {
         printk("====[ backtrace testing ]===========\n");
-        printk("Testing a backtrace from process context.\n");
-        printk("The following trace is a kernel self test and not a bug!\n");
-        dump_stack();
 
-        init_timer(&backtrace_timer);
-        backtrace_timer.function = backtrace_test_timer;
-        mod_timer(&backtrace_timer, jiffies + 10);
+        backtrace_test_normal();
+        backtrace_test_irq();
+        backtrace_test_saved();
 
-        msleep(10);
         printk("====[ end of backtrace testing ]====\n");
         return 0;
 }
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index b71816e47a30..94b527ef1d1e 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -6,19 +6,21 @@
  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
  */
 #include <linux/sched.h>
+#include <linux/module.h>
 #include <linux/kallsyms.h>
 #include <linux/stacktrace.h>
 
 void print_stack_trace(struct stack_trace *trace, int spaces)
 {
-        int i, j;
+        int i;
 
-        for (i = 0; i < trace->nr_entries; i++) {
-                unsigned long ip = trace->entries[i];
+        if (WARN_ON(!trace->entries))
+                return;
 
-                for (j = 0; j < spaces + 1; j++)
-                        printk(" ");
-                print_ip_sym(ip);
+        for (i = 0; i < trace->nr_entries; i++) {
+                printk("%*c", 1 + spaces, ' ');
+                print_ip_sym(trace->entries[i]);
         }
 }
+EXPORT_SYMBOL_GPL(print_stack_trace);