[PATCH] fault injection: stacktrace filtering

[safe/jmp/linux-2.6] / lib / fault-inject.c

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 0346860..361c6e9 100644 (file)
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -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>
 
 /*
@@ -50,6 +53,86 @@ static int fail_task(struct fault_attr *attr, struct task_struct *task)
        return !in_interrupt() && task->make_it_fail;
 }
 
+#ifdef CONFIG_STACK_UNWIND
+
+static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
+                                               void *arg)
+{
+       int depth;
+       struct fault_attr *attr = arg;
+       bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
+
+       for (depth = 0; depth < attr->stacktrace_depth
+                       && unwind(info) == 0 && UNW_PC(info); depth++) {
+               if (arch_unw_user_mode(info))
+                       break;
+               if (attr->reject_start <= UNW_PC(info) &&
+                              UNW_PC(info) < attr->reject_end)
+                       return 0;
+               if (attr->require_start <= UNW_PC(info) &&
+                              UNW_PC(info) < attr->require_end)
+                       found = 1;
+       }
+       return found;
+}
+
+static int fail_stacktrace(struct fault_attr *attr)
+{
+       struct unwind_frame_info info;
+
+       return unwind_init_running(&info, fail_stacktrace_callback, attr);
+}
+
+#elif defined(CONFIG_STACKTRACE)
+
+#define MAX_STACK_TRACE_DEPTH 32
+
+static int 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 < MAX_STACK_TRACE_DEPTH) ?
+                               depth : MAX_STACK_TRACE_DEPTH;
+       trace.skip = 1;
+       trace.all_contexts = 0;
+
+       save_stack_trace(&trace, NULL);
+       for (n = 0; n < trace.nr_entries; n++) {
+               if (attr->reject_start <= entries[n] &&
+                              entries[n] < attr->reject_end)
+                       return 0;
+               if (attr->require_start <= entries[n] &&
+                              entries[n] < attr->require_end)
+                       found = 1;
+       }
+       return found;
+}
+
+#else
+
+static inline int fail_stacktrace(struct fault_attr *attr)
+{
+       static int firsttime = 1;
+
+       if (firsttime) {
+               printk(KERN_WARNING
+               "This architecture does not implement save_stack_trace()\n");
+               firsttime = 0;
+       }
+       return 0;
+}
+
+#endif
+
 /*
  * This code is stolen from failmalloc-1.0
  * http://www.nongnu.org/failmalloc/
@@ -60,6 +143,9 @@ int should_fail(struct fault_attr *attr, ssize_t size)
        if (attr->task_filter && !fail_task(attr, current))
                return 0;
 
+       if (!fail_stacktrace(attr))
+               return 0;
+
        if (atomic_read(&attr->times) == 0)
                return 0;
 
@@ -147,6 +233,21 @@ void cleanup_fault_attr_dentries(struct fault_attr *attr)
        debugfs_remove(attr->dentries.task_filter_file);
        attr->dentries.task_filter_file = NULL;
 
+       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;
+
        if (attr->dentries.dir)
                WARN_ON(!simple_empty(attr->dentries.dir));
 
@@ -184,9 +285,32 @@ 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);
 
+       attr->dentries.stacktrace_depth_file =
+               debugfs_create_ul("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.probability_file || !attr->dentries.interval_file
            || !attr->dentries.times_file || !attr->dentries.space_file
-           || !attr->dentries.verbose_file || !attr->dentries.task_filter_file)
+           || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
+           || !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;
 
        return 0;