The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/lib/fault-inject.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 #include <linux/kernel.h>
    2 #include <linux/init.h>
    3 #include <linux/random.h>
    4 #include <linux/sched.h>
    5 #include <linux/stat.h>
    6 #include <linux/types.h>
    7 #include <linux/fs.h>
    8 #include <linux/export.h>
    9 #include <linux/interrupt.h>
   10 #include <linux/stacktrace.h>
   11 #include <linux/fault-inject.h>
   12 
   13 /*
   14  * setup_fault_attr() is a helper function for various __setup handlers, so it
   15  * returns 0 on error, because that is what __setup handlers do.
   16  */
   17 int setup_fault_attr(struct fault_attr *attr, char *str)
   18 {
   19         unsigned long probability;
   20         unsigned long interval;
   21         int times;
   22         int space;
   23 
   24         /* "<interval>,<probability>,<space>,<times>" */
   25         if (sscanf(str, "%lu,%lu,%d,%d",
   26                         &interval, &probability, &space, &times) < 4) {
   27                 printk(KERN_WARNING
   28                         "FAULT_INJECTION: failed to parse arguments\n");
   29                 return 0;
   30         }
   31 
   32         attr->probability = probability;
   33         attr->interval = interval;
   34         atomic_set(&attr->times, times);
   35         atomic_set(&attr->space, space);
   36 
   37         return 1;
   38 }
   39 EXPORT_SYMBOL_GPL(setup_fault_attr);
   40 
   41 static void fail_dump(struct fault_attr *attr)
   42 {
   43         if (attr->verbose > 0)
   44                 printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
   45         if (attr->verbose > 1)
   46                 dump_stack();
   47 }
   48 
   49 #define atomic_dec_not_zero(v)          atomic_add_unless((v), -1, 0)
   50 
   51 static bool fail_task(struct fault_attr *attr, struct task_struct *task)
   52 {
   53         return !in_interrupt() && task->make_it_fail;
   54 }
   55 
   56 #define MAX_STACK_TRACE_DEPTH 32
   57 
   58 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
   59 
   60 static bool fail_stacktrace(struct fault_attr *attr)
   61 {
   62         struct stack_trace trace;
   63         int depth = attr->stacktrace_depth;
   64         unsigned long entries[MAX_STACK_TRACE_DEPTH];
   65         int n;
   66         bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
   67 
   68         if (depth == 0)
   69                 return found;
   70 
   71         trace.nr_entries = 0;
   72         trace.entries = entries;
   73         trace.max_entries = depth;
   74         trace.skip = 1;
   75 
   76         save_stack_trace(&trace);
   77         for (n = 0; n < trace.nr_entries; n++) {
   78                 if (attr->reject_start <= entries[n] &&
   79                                entries[n] < attr->reject_end)
   80                         return false;
   81                 if (attr->require_start <= entries[n] &&
   82                                entries[n] < attr->require_end)
   83                         found = true;
   84         }
   85         return found;
   86 }
   87 
   88 #else
   89 
   90 static inline bool fail_stacktrace(struct fault_attr *attr)
   91 {
   92         return true;
   93 }
   94 
   95 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
   96 
   97 /*
   98  * This code is stolen from failmalloc-1.0
   99  * http://www.nongnu.org/failmalloc/
  100  */
  101 
  102 bool should_fail(struct fault_attr *attr, ssize_t size)
  103 {
  104         /* No need to check any other properties if the probability is 0 */
  105         if (attr->probability == 0)
  106                 return false;
  107 
  108         if (attr->task_filter && !fail_task(attr, current))
  109                 return false;
  110 
  111         if (atomic_read(&attr->times) == 0)
  112                 return false;
  113 
  114         if (atomic_read(&attr->space) > size) {
  115                 atomic_sub(size, &attr->space);
  116                 return false;
  117         }
  118 
  119         if (attr->interval > 1) {
  120                 attr->count++;
  121                 if (attr->count % attr->interval)
  122                         return false;
  123         }
  124 
  125         if (attr->probability <= random32() % 100)
  126                 return false;
  127 
  128         if (!fail_stacktrace(attr))
  129                 return false;
  130 
  131         fail_dump(attr);
  132 
  133         if (atomic_read(&attr->times) != -1)
  134                 atomic_dec_not_zero(&attr->times);
  135 
  136         return true;
  137 }
  138 EXPORT_SYMBOL_GPL(should_fail);
  139 
  140 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
  141 
  142 static int debugfs_ul_set(void *data, u64 val)
  143 {
  144         *(unsigned long *)data = val;
  145         return 0;
  146 }
  147 
  148 static int debugfs_ul_get(void *data, u64 *val)
  149 {
  150         *val = *(unsigned long *)data;
  151         return 0;
  152 }
  153 
  154 DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
  155 
  156 static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
  157                                 struct dentry *parent, unsigned long *value)
  158 {
  159         return debugfs_create_file(name, mode, parent, value, &fops_ul);
  160 }
  161 
  162 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
  163 
  164 static int debugfs_stacktrace_depth_set(void *data, u64 val)
  165 {
  166         *(unsigned long *)data =
  167                 min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
  168 
  169         return 0;
  170 }
  171 
  172 DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
  173                         debugfs_stacktrace_depth_set, "%llu\n");
  174 
  175 static struct dentry *debugfs_create_stacktrace_depth(
  176         const char *name, umode_t mode,
  177         struct dentry *parent, unsigned long *value)
  178 {
  179         return debugfs_create_file(name, mode, parent, value,
  180                                    &fops_stacktrace_depth);
  181 }
  182 
  183 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
  184 
  185 static int debugfs_atomic_t_set(void *data, u64 val)
  186 {
  187         atomic_set((atomic_t *)data, val);
  188         return 0;
  189 }
  190 
  191 static int debugfs_atomic_t_get(void *data, u64 *val)
  192 {
  193         *val = atomic_read((atomic_t *)data);
  194         return 0;
  195 }
  196 
  197 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
  198                         debugfs_atomic_t_set, "%lld\n");
  199 
  200 static struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
  201                                 struct dentry *parent, atomic_t *value)
  202 {
  203         return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
  204 }
  205 
  206 struct dentry *fault_create_debugfs_attr(const char *name,
  207                         struct dentry *parent, struct fault_attr *attr)
  208 {
  209         umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
  210         struct dentry *dir;
  211 
  212         dir = debugfs_create_dir(name, parent);
  213         if (!dir)
  214                 return ERR_PTR(-ENOMEM);
  215 
  216         if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
  217                 goto fail;
  218         if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
  219                 goto fail;
  220         if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
  221                 goto fail;
  222         if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
  223                 goto fail;
  224         if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
  225                 goto fail;
  226         if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
  227                 goto fail;
  228 
  229 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
  230 
  231         if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
  232                                 &attr->stacktrace_depth))
  233                 goto fail;
  234         if (!debugfs_create_ul("require-start", mode, dir,
  235                                 &attr->require_start))
  236                 goto fail;
  237         if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
  238                 goto fail;
  239         if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
  240                 goto fail;
  241         if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
  242                 goto fail;
  243 
  244 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
  245 
  246         return dir;
  247 fail:
  248         debugfs_remove_recursive(dir);
  249 
  250         return ERR_PTR(-ENOMEM);
  251 }
  252 EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
  253 
  254 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

Cache object: 4e30d90cd6a9f41b71442ea218239fc5


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.