stacktrace: add saved stack traces to backtrace self-test

This patch adds saved stack-traces to the backtrace suite of self-tests.

Note that we don't depend on or unconditionally enable CONFIG_STACKTRACE
because not all architectures may have it (and we still want to enable the
other tests for those architectures).

Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/backtracetest.c b/kernel/backtracetest.c
index d1a7605c5b8fe01368e7290f2d215512d646cc32..50f7abd0813df0abd436391244bb3f1ca98bff99 100644 (file)
--- a/kernel/backtracetest.c
+++ b/kernel/backtracetest.c
@@ -10,9 +10,10 @@
  * of the License.
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/sched.h>
-#include <linux/delay.h>
+#include <linux/stacktrace.h>
 
 static struct timer_list backtrace_timer;
 
@@ -22,6 +23,31 @@ static void backtrace_test_timer(unsigned long data)
        printk("The following trace is a kernel self test and not a bug!\n");
        dump_stack();
 }
+
+#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");
@@ -29,6 +55,8 @@ static int backtrace_regression_test(void)
        printk("The following trace is a kernel self test and not a bug!\n");
        dump_stack();
 
+       backtrace_test_saved();
+
        init_timer(&backtrace_timer);
        backtrace_timer.function = backtrace_test_timer;
        mod_timer(&backtrace_timer, jiffies + 10);

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9c17fb9d1d5e4c88c71673cbdb977f8adb97a942..6263e2d851f1f0d9b4201d15a678f0871c889dd1 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -562,6 +562,9 @@ config BACKTRACE_SELF_TEST
          for distributions or general kernels, but only for kernel
          developers working on architecture code.
 
+         Note that if you want to also test saved backtraces, you will
+         have to enable STACKTRACE as well.
+
          Say N if you are unsure.
 
 config LKDTM