kernel/test_kprobes.c

   1 /*
   2  * test_kprobes.c - simple sanity test for *probes
   3  *
   4  * Copyright IBM Corp. 2008
   5  *
   6  * This program is free software;  you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it would be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  14  * the GNU General Public License for more details.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/kprobes.h>
  19 #include <linux/random.h>
  20
  21 #define div_factor 3
  22
  23 static u32 rand1, preh_val, posth_val, jph_val;
  24 static int errors, handler_errors, num_tests;
  25 static u32 (*target)(u32 value);
  26 static u32 (*target2)(u32 value);
  27
  28 static noinline u32 kprobe_target(u32 value)
  29 {
  30         return (value / div_factor);
  31 }
  32
  33 static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
  34 {
  35         preh_val = (rand1 / div_factor);
  36         return 0;
  37 }
  38
  39 static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
  40                 unsigned long flags)
  41 {
  42         if (preh_val != (rand1 / div_factor)) {
  43                 handler_errors++;
  44                 printk(KERN_ERR "Kprobe smoke test failed: "
  45                                 "incorrect value in post_handler\n");
  46         }
  47         posth_val = preh_val + div_factor;
  48 }
  49
  50 static struct kprobe kp = {
  51         .symbol_name = "kprobe_target",
  52         .pre_handler = kp_pre_handler,
  53         .post_handler = kp_post_handler
  54 };
  55
  56 static int test_kprobe(void)
  57 {
  58         int ret;
  59
  60         ret = register_kprobe(&kp);
  61         if (ret < 0) {
  62                 printk(KERN_ERR "Kprobe smoke test failed: "
  63                                 "register_kprobe returned %d\n", ret);
  64                 return ret;
  65         }
  66
  67         ret = target(rand1);
  68         unregister_kprobe(&kp);
  69
  70         if (preh_val == 0) {
  71                 printk(KERN_ERR "Kprobe smoke test failed: "
  72                                 "kprobe pre_handler not called\n");
  73                 handler_errors++;
  74         }
  75
  76         if (posth_val == 0) {
  77                 printk(KERN_ERR "Kprobe smoke test failed: "
  78                                 "kprobe post_handler not called\n");
  79                 handler_errors++;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static noinline u32 kprobe_target2(u32 value)
  86 {
  87         return (value / div_factor) + 1;
  88 }
  89
  90 static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
  91 {
  92         preh_val = (rand1 / div_factor) + 1;
  93         return 0;
  94 }
  95
  96 static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs,
  97                 unsigned long flags)
  98 {
  99         if (preh_val != (rand1 / div_factor) + 1) {
 100                 handler_errors++;
 101                 printk(KERN_ERR "Kprobe smoke test failed: "
 102                                 "incorrect value in post_handler2\n");
 103         }
 104         posth_val = preh_val + div_factor;
 105 }
 106
 107 static struct kprobe kp2 = {
 108         .symbol_name = "kprobe_target2",
 109         .pre_handler = kp_pre_handler2,
 110         .post_handler = kp_post_handler2
 111 };
 112
 113 static int test_kprobes(void)
 114 {
 115         int ret;
 116         struct kprobe *kps[2] = {&kp, &kp2};
 117
 118         /* addr and flags should be cleard for reusing kprobe. */
 119         kp.addr = NULL;
 120         kp.flags = 0;
 121         ret = register_kprobes(kps, 2);
 122         if (ret < 0) {
 123                 printk(KERN_ERR "Kprobe smoke test failed: "
 124                                 "register_kprobes returned %d\n", ret);
 125                 return ret;
 126         }
 127
 128         preh_val = 0;
 129         posth_val = 0;
 130         ret = target(rand1);
 131
 132         if (preh_val == 0) {
 133                 printk(KERN_ERR "Kprobe smoke test failed: "
 134                                 "kprobe pre_handler not called\n");
 135                 handler_errors++;
 136         }
 137
 138         if (posth_val == 0) {
 139                 printk(KERN_ERR "Kprobe smoke test failed: "
 140                                 "kprobe post_handler not called\n");
 141                 handler_errors++;
 142         }
 143
 144         preh_val = 0;
 145         posth_val = 0;
 146         ret = target2(rand1);
 147
 148         if (preh_val == 0) {
 149                 printk(KERN_ERR "Kprobe smoke test failed: "
 150                                 "kprobe pre_handler2 not called\n");
 151                 handler_errors++;
 152         }
 153
 154         if (posth_val == 0) {
 155                 printk(KERN_ERR "Kprobe smoke test failed: "
 156                                 "kprobe post_handler2 not called\n");
 157                 handler_errors++;
 158         }
 159
 160         unregister_kprobes(kps, 2);
 161         return 0;
 162
 163 }
 164
 165 static u32 j_kprobe_target(u32 value)
 166 {
 167         if (value != rand1) {
 168                 handler_errors++;
 169                 printk(KERN_ERR "Kprobe smoke test failed: "
 170                                 "incorrect value in jprobe handler\n");
 171         }
 172
 173         jph_val = rand1;
 174         jprobe_return();
 175         return 0;
 176 }
 177
 178 static struct jprobe jp = {
 179         .entry          = j_kprobe_target,
 180         .kp.symbol_name = "kprobe_target"
 181 };
 182
 183 static int test_jprobe(void)
 184 {
 185         int ret;
 186
 187         ret = register_jprobe(&jp);
 188         if (ret < 0) {
 189                 printk(KERN_ERR "Kprobe smoke test failed: "
 190                                 "register_jprobe returned %d\n", ret);
 191                 return ret;
 192         }
 193
 194         ret = target(rand1);
 195         unregister_jprobe(&jp);
 196         if (jph_val == 0) {
 197                 printk(KERN_ERR "Kprobe smoke test failed: "
 198                                 "jprobe handler not called\n");
 199                 handler_errors++;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static struct jprobe jp2 = {
 206         .entry          = j_kprobe_target,
 207         .kp.symbol_name = "kprobe_target2"
 208 };
 209
 210 static int test_jprobes(void)
 211 {
 212         int ret;
 213         struct jprobe *jps[2] = {&jp, &jp2};
 214
 215         /* addr and flags should be cleard for reusing kprobe. */
 216         jp.kp.addr = NULL;
 217         jp.kp.flags = 0;
 218         ret = register_jprobes(jps, 2);
 219         if (ret < 0) {
 220                 printk(KERN_ERR "Kprobe smoke test failed: "
 221                                 "register_jprobes returned %d\n", ret);
 222                 return ret;
 223         }
 224
 225         jph_val = 0;
 226         ret = target(rand1);
 227         if (jph_val == 0) {
 228                 printk(KERN_ERR "Kprobe smoke test failed: "
 229                                 "jprobe handler not called\n");
 230                 handler_errors++;
 231         }
 232
 233         jph_val = 0;
 234         ret = target2(rand1);
 235         if (jph_val == 0) {
 236                 printk(KERN_ERR "Kprobe smoke test failed: "
 237                                 "jprobe handler2 not called\n");
 238                 handler_errors++;
 239         }
 240         unregister_jprobes(jps, 2);
 241
 242         return 0;
 243 }
 244 #ifdef CONFIG_KRETPROBES
 245 static u32 krph_val;
 246
 247 static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 248 {
 249         krph_val = (rand1 / div_factor);
 250         return 0;
 251 }
 252
 253 static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 254 {
 255         unsigned long ret = regs_return_value(regs);
 256
 257         if (ret != (rand1 / div_factor)) {
 258                 handler_errors++;
 259                 printk(KERN_ERR "Kprobe smoke test failed: "
 260                                 "incorrect value in kretprobe handler\n");
 261         }
 262         if (krph_val == 0) {
 263                 handler_errors++;
 264                 printk(KERN_ERR "Kprobe smoke test failed: "
 265                                 "call to kretprobe entry handler failed\n");
 266         }
 267
 268         krph_val = rand1;
 269         return 0;
 270 }
 271
 272 static struct kretprobe rp = {
 273         .handler        = return_handler,
 274         .entry_handler  = entry_handler,
 275         .kp.symbol_name = "kprobe_target"
 276 };
 277
 278 static int test_kretprobe(void)
 279 {
 280         int ret;
 281
 282         ret = register_kretprobe(&rp);
 283         if (ret < 0) {
 284                 printk(KERN_ERR "Kprobe smoke test failed: "
 285                                 "register_kretprobe returned %d\n", ret);
 286                 return ret;
 287         }
 288
 289         ret = target(rand1);
 290         unregister_kretprobe(&rp);
 291         if (krph_val != rand1) {
 292                 printk(KERN_ERR "Kprobe smoke test failed: "
 293                                 "kretprobe handler not called\n");
 294                 handler_errors++;
 295         }
 296
 297         return 0;
 298 }
 299
 300 static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
 301 {
 302         unsigned long ret = regs_return_value(regs);
 303
 304         if (ret != (rand1 / div_factor) + 1) {
 305                 handler_errors++;
 306                 printk(KERN_ERR "Kprobe smoke test failed: "
 307                                 "incorrect value in kretprobe handler2\n");
 308         }
 309         if (krph_val == 0) {
 310                 handler_errors++;
 311                 printk(KERN_ERR "Kprobe smoke test failed: "
 312                                 "call to kretprobe entry handler failed\n");
 313         }
 314
 315         krph_val = rand1;
 316         return 0;
 317 }
 318
 319 static struct kretprobe rp2 = {
 320         .handler        = return_handler2,
 321         .entry_handler  = entry_handler,
 322         .kp.symbol_name = "kprobe_target2"
 323 };
 324
 325 static int test_kretprobes(void)
 326 {
 327         int ret;
 328         struct kretprobe *rps[2] = {&rp, &rp2};
 329
 330         /* addr and flags should be cleard for reusing kprobe. */
 331         rp.kp.addr = NULL;
 332         rp.kp.flags = 0;
 333         ret = register_kretprobes(rps, 2);
 334         if (ret < 0) {
 335                 printk(KERN_ERR "Kprobe smoke test failed: "
 336                                 "register_kretprobe returned %d\n", ret);
 337                 return ret;
 338         }
 339
 340         krph_val = 0;
 341         ret = target(rand1);
 342         if (krph_val != rand1) {
 343                 printk(KERN_ERR "Kprobe smoke test failed: "
 344                                 "kretprobe handler not called\n");
 345                 handler_errors++;
 346         }
 347
 348         krph_val = 0;
 349         ret = target2(rand1);
 350         if (krph_val != rand1) {
 351                 printk(KERN_ERR "Kprobe smoke test failed: "
 352                                 "kretprobe handler2 not called\n");
 353                 handler_errors++;
 354         }
 355         unregister_kretprobes(rps, 2);
 356         return 0;
 357 }
 358 #endif /* CONFIG_KRETPROBES */
 359
 360 int init_test_probes(void)
 361 {
 362         int ret;
 363
 364         target = kprobe_target;
 365         target2 = kprobe_target2;
 366
 367         do {
 368                 rand1 = prandom_u32();
 369         } while (rand1 <= div_factor);
 370
 371         printk(KERN_INFO "Kprobe smoke test started\n");
 372         num_tests++;
 373         ret = test_kprobe();
 374         if (ret < 0)
 375                 errors++;
 376
 377         num_tests++;
 378         ret = test_kprobes();
 379         if (ret < 0)
 380                 errors++;
 381
 382         num_tests++;
 383         ret = test_jprobe();
 384         if (ret < 0)
 385                 errors++;
 386
 387         num_tests++;
 388         ret = test_jprobes();
 389         if (ret < 0)
 390                 errors++;
 391
 392 #ifdef CONFIG_KRETPROBES
 393         num_tests++;
 394         ret = test_kretprobe();
 395         if (ret < 0)
 396                 errors++;
 397
 398         num_tests++;
 399         ret = test_kretprobes();
 400         if (ret < 0)
 401                 errors++;
 402 #endif /* CONFIG_KRETPROBES */
 403
 404         if (errors)
 405                 printk(KERN_ERR "BUG: Kprobe smoke test: %d out of "
 406                                 "%d tests failed\n", errors, num_tests);
 407         else if (handler_errors)
 408                 printk(KERN_ERR "BUG: Kprobe smoke test: %d error(s) "
 409                                 "running handlers\n", handler_errors);
 410         else
 411                 printk(KERN_INFO "Kprobe smoke test passed successfully\n");
 412
 413         return 0;
 414 }