sched: latencytop support
[linux-2.6.git] / lib / fault-inject.c
index 0346860..23985a2 100644 (file)
@@ -6,6 +6,9 @@
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
+#include <linux/unwind.h>
+#include <linux/stacktrace.h>
+#include <linux/kallsyms.h>
 #include <linux/fault-inject.h>
 
 /*
@@ -45,47 +48,88 @@ static void fail_dump(struct fault_attr *attr)
 
 #define atomic_dec_not_zero(v)         atomic_add_unless((v), -1, 0)
 
-static int fail_task(struct fault_attr *attr, struct task_struct *task)
+static bool fail_task(struct fault_attr *attr, struct task_struct *task)
 {
        return !in_interrupt() && task->make_it_fail;
 }
 
+#define MAX_STACK_TRACE_DEPTH 32
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+static bool fail_stacktrace(struct fault_attr *attr)
+{
+       struct stack_trace trace;
+       int depth = attr->stacktrace_depth;
+       unsigned long entries[MAX_STACK_TRACE_DEPTH];
+       int n;
+       bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
+
+       if (depth == 0)
+               return found;
+
+       trace.nr_entries = 0;
+       trace.entries = entries;
+       trace.max_entries = depth;
+       trace.skip = 1;
+
+       save_stack_trace(&trace);
+       for (n = 0; n < trace.nr_entries; n++) {
+               if (attr->reject_start <= entries[n] &&
+                              entries[n] < attr->reject_end)
+                       return false;
+               if (attr->require_start <= entries[n] &&
+                              entries[n] < attr->require_end)
+                       found = true;
+       }
+       return found;
+}
+
+#else
+
+static inline bool fail_stacktrace(struct fault_attr *attr)
+{
+       return true;
+}
+
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
 /*
  * This code is stolen from failmalloc-1.0
  * http://www.nongnu.org/failmalloc/
  */
 
-int should_fail(struct fault_attr *attr, ssize_t size)
+bool should_fail(struct fault_attr *attr, ssize_t size)
 {
        if (attr->task_filter && !fail_task(attr, current))
-               return 0;
+               return false;
 
        if (atomic_read(&attr->times) == 0)
-               return 0;
+               return false;
 
        if (atomic_read(&attr->space) > size) {
                atomic_sub(size, &attr->space);
-               return 0;
+               return false;
        }
 
        if (attr->interval > 1) {
                attr->count++;
                if (attr->count % attr->interval)
-                       return 0;
+                       return false;
        }
 
-       if (attr->probability > random32() % 100)
-               goto fail;
+       if (attr->probability <= random32() % 100)
+               return false;
 
-       return 0;
+       if (!fail_stacktrace(attr))
+               return false;
 
-fail:
        fail_dump(attr);
 
        if (atomic_read(&attr->times) != -1)
                atomic_dec_not_zero(&attr->times);
 
-       return 1;
+       return true;
 }
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
@@ -95,6 +139,15 @@ static void debugfs_ul_set(void *data, u64 val)
        *(unsigned long *)data = val;
 }
 
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
+{
+       *(unsigned long *)data =
+               val < MAX_STACK_TRACE_DEPTH ?
+               val : MAX_STACK_TRACE_DEPTH;
+}
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
 static u64 debugfs_ul_get(void *data)
 {
        return *(unsigned long *)data;
@@ -108,6 +161,19 @@ static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
        return debugfs_create_file(name, mode, parent, value, &fops_ul);
 }
 
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
+                       debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
+
+static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
+       const char *name, mode_t mode,
+       struct dentry *parent, unsigned long *value)
+{
+       return debugfs_create_file(name, mode, parent, value,
+                                  &fops_ul_MAX_STACK_TRACE_DEPTH);
+}
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
 static void debugfs_atomic_t_set(void *data, u64 val)
 {
        atomic_set((atomic_t *)data, val);
@@ -147,6 +213,25 @@ void cleanup_fault_attr_dentries(struct fault_attr *attr)
        debugfs_remove(attr->dentries.task_filter_file);
        attr->dentries.task_filter_file = NULL;
 
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+       debugfs_remove(attr->dentries.stacktrace_depth_file);
+       attr->dentries.stacktrace_depth_file = NULL;
+
+       debugfs_remove(attr->dentries.require_start_file);
+       attr->dentries.require_start_file = NULL;
+
+       debugfs_remove(attr->dentries.require_end_file);
+       attr->dentries.require_end_file = NULL;
+
+       debugfs_remove(attr->dentries.reject_start_file);
+       attr->dentries.reject_start_file = NULL;
+
+       debugfs_remove(attr->dentries.reject_end_file);
+       attr->dentries.reject_end_file = NULL;
+
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
        if (attr->dentries.dir)
                WARN_ON(!simple_empty(attr->dentries.dir));
 
@@ -184,11 +269,38 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
        attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
                                                mode, dir, &attr->task_filter);
 
-       if (!attr->dentries.probability_file || !attr->dentries.interval_file
-           || !attr->dentries.times_file || !attr->dentries.space_file
-           || !attr->dentries.verbose_file || !attr->dentries.task_filter_file)
+       if (!attr->dentries.probability_file || !attr->dentries.interval_file ||
+           !attr->dentries.times_file || !attr->dentries.space_file ||
+           !attr->dentries.verbose_file || !attr->dentries.task_filter_file)
+               goto fail;
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+       attr->dentries.stacktrace_depth_file =
+               debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
+                       "stacktrace-depth", mode, dir, &attr->stacktrace_depth);
+
+       attr->dentries.require_start_file =
+               debugfs_create_ul("require-start", mode, dir, &attr->require_start);
+
+       attr->dentries.require_end_file =
+               debugfs_create_ul("require-end", mode, dir, &attr->require_end);
+
+       attr->dentries.reject_start_file =
+               debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
+
+       attr->dentries.reject_end_file =
+               debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
+
+       if (!attr->dentries.stacktrace_depth_file ||
+           !attr->dentries.require_start_file ||
+           !attr->dentries.require_end_file ||
+           !attr->dentries.reject_start_file ||
+           !attr->dentries.reject_end_file)
                goto fail;
 
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
        return 0;
 fail:
        cleanup_fault_attr_dentries(attr);