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   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         kp.addr = 0; /* addr should be cleard for reusing kprobe. */
 119         ret = register_kprobes(kps, 2);
 120         if (ret < 0) {
 121                 printk(KERN_ERR "Kprobe smoke test failed: "
 122                                 "register_kprobes returned %d\n", ret);
 123                 return ret;
 124         }
 125
 126         preh_val = 0;
 127         posth_val = 0;
 128         ret = target(rand1);
 129
 130         if (preh_val == 0) {
 131                 printk(KERN_ERR "Kprobe smoke test failed: "
 132                                 "kprobe pre_handler not called\n");
 133                 handler_errors++;
 134         }
 135
 136         if (posth_val == 0) {
 137                 printk(KERN_ERR "Kprobe smoke test failed: "
 138                                 "kprobe post_handler not called\n");
 139                 handler_errors++;
 140         }
 141
 142         preh_val = 0;
 143         posth_val = 0;
 144         ret = target2(rand1);
 145
 146         if (preh_val == 0) {
 147                 printk(KERN_ERR "Kprobe smoke test failed: "
 148                                 "kprobe pre_handler2 not called\n");
 149                 handler_errors++;
 150         }
 151
 152         if (posth_val == 0) {
 153                 printk(KERN_ERR "Kprobe smoke test failed: "
 154                                 "kprobe post_handler2 not called\n");
 155                 handler_errors++;
 156         }
 157
 158         unregister_kprobes(kps, 2);
 159         return 0;
 160
 161 }
 162
 163 static u32 j_kprobe_target(u32 value)
 164 {
 165         if (value != rand1) {
 166                 handler_errors++;
 167                 printk(KERN_ERR "Kprobe smoke test failed: "
 168                                 "incorrect value in jprobe handler\n");
 169         }
 170
 171         jph_val = rand1;
 172         jprobe_return();
 173         return 0;
 174 }
 175
 176 static struct jprobe jp = {
 177         .entry          = j_kprobe_target,
 178         .kp.symbol_name = "kprobe_target"
 179 };
 180
 181 static int test_jprobe(void)
 182 {
 183         int ret;
 184
 185         ret = register_jprobe(&jp);
 186         if (ret < 0) {
 187                 printk(KERN_ERR "Kprobe smoke test failed: "
 188                                 "register_jprobe returned %d\n", ret);
 189                 return ret;
 190         }
 191
 192         ret = target(rand1);
 193         unregister_jprobe(&jp);
 194         if (jph_val == 0) {
 195                 printk(KERN_ERR "Kprobe smoke test failed: "
 196                                 "jprobe handler not called\n");
 197                 handler_errors++;
 198         }
 199
 200         return 0;
 201 }
 202
 203 static struct jprobe jp2 = {
 204         .entry          = j_kprobe_target,
 205         .kp.symbol_name = "kprobe_target2"
 206 };
 207
 208 static int test_jprobes(void)
 209 {
 210         int ret;
 211         struct jprobe *jps[2] = {&jp, &jp2};
 212
 213         jp.kp.addr = 0; /* addr should be cleard for reusing kprobe. */
 214         ret = register_jprobes(jps, 2);
 215         if (ret < 0) {
 216                 printk(KERN_ERR "Kprobe smoke test failed: "
 217                                 "register_jprobes returned %d\n", ret);
 218                 return ret;
 219         }
 220
 221         jph_val = 0;
 222         ret = target(rand1);
 223         if (jph_val == 0) {
 224                 printk(KERN_ERR "Kprobe smoke test failed: "
 225                                 "jprobe handler not called\n");
 226                 handler_errors++;
 227         }
 228
 229         jph_val = 0;
 230         ret = target2(rand1);
 231         if (jph_val == 0) {
 232                 printk(KERN_ERR "Kprobe smoke test failed: "
 233                                 "jprobe handler2 not called\n");
 234                 handler_errors++;
 235         }
 236         unregister_jprobes(jps, 2);
 237
 238         return 0;
 239 }
 240 #ifdef CONFIG_KRETPROBES
 241 static u32 krph_val;
 242
 243 static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 244 {
 245         krph_val = (rand1 / div_factor);
 246         return 0;
 247 }
 248
 249 static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 250 {
 251         unsigned long ret = regs_return_value(regs);
 252
 253         if (ret != (rand1 / div_factor)) {
 254                 handler_errors++;
 255                 printk(KERN_ERR "Kprobe smoke test failed: "
 256                                 "incorrect value in kretprobe handler\n");
 257         }
 258         if (krph_val == 0) {
 259                 handler_errors++;
 260                 printk(KERN_ERR "Kprobe smoke test failed: "
 261                                 "call to kretprobe entry handler failed\n");
 262         }
 263
 264         krph_val = rand1;
 265         return 0;
 266 }
 267
 268 static struct kretprobe rp = {
 269         .handler        = return_handler,
 270         .entry_handler  = entry_handler,
 271         .kp.symbol_name = "kprobe_target"
 272 };
 273
 274 static int test_kretprobe(void)
 275 {
 276         int ret;
 277
 278         ret = register_kretprobe(&rp);
 279         if (ret < 0) {
 280                 printk(KERN_ERR "Kprobe smoke test failed: "
 281                                 "register_kretprobe returned %d\n", ret);
 282                 return ret;
 283         }
 284
 285         ret = target(rand1);
 286         unregister_kretprobe(&rp);
 287         if (krph_val != rand1) {
 288                 printk(KERN_ERR "Kprobe smoke test failed: "
 289                                 "kretprobe handler not called\n");
 290                 handler_errors++;
 291         }
 292
 293         return 0;
 294 }
 295
 296 static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
 297 {
 298         unsigned long ret = regs_return_value(regs);
 299
 300         if (ret != (rand1 / div_factor) + 1) {
 301                 handler_errors++;
 302                 printk(KERN_ERR "Kprobe smoke test failed: "
 303                                 "incorrect value in kretprobe handler2\n");
 304         }
 305         if (krph_val == 0) {
 306                 handler_errors++;
 307                 printk(KERN_ERR "Kprobe smoke test failed: "
 308                                 "call to kretprobe entry handler failed\n");
 309         }
 310
 311         krph_val = rand1;
 312         return 0;
 313 }
 314
 315 static struct kretprobe rp2 = {
 316         .handler        = return_handler2,
 317         .entry_handler  = entry_handler,
 318         .kp.symbol_name = "kprobe_target2"
 319 };
 320
 321 static int test_kretprobes(void)
 322 {
 323         int ret;
 324         struct kretprobe *rps[2] = {&rp, &rp2};
 325
 326         rp.kp.addr = 0; /* addr should be cleard for reusing kprobe. */
 327         ret = register_kretprobes(rps, 2);
 328         if (ret < 0) {
 329                 printk(KERN_ERR "Kprobe smoke test failed: "
 330                                 "register_kretprobe returned %d\n", ret);
 331                 return ret;
 332         }
 333
 334         krph_val = 0;
 335         ret = target(rand1);
 336         if (krph_val != rand1) {
 337                 printk(KERN_ERR "Kprobe smoke test failed: "
 338                                 "kretprobe handler not called\n");
 339                 handler_errors++;
 340         }
 341
 342         krph_val = 0;
 343         ret = target2(rand1);
 344         if (krph_val != rand1) {
 345                 printk(KERN_ERR "Kprobe smoke test failed: "
 346                                 "kretprobe handler2 not called\n");
 347                 handler_errors++;
 348         }
 349         unregister_kretprobes(rps, 2);
 350         return 0;
 351 }
 352 #endif /* CONFIG_KRETPROBES */
 353
 354 int init_test_probes(void)
 355 {
 356         int ret;
 357
 358         target = kprobe_target;
 359         target2 = kprobe_target2;
 360
 361         do {
 362                 rand1 = random32();
 363         } while (rand1 <= div_factor);
 364
 365         printk(KERN_INFO "Kprobe smoke test started\n");
 366         num_tests++;
 367         ret = test_kprobe();
 368         if (ret < 0)
 369                 errors++;
 370
 371         num_tests++;
 372         ret = test_kprobes();
 373         if (ret < 0)
 374                 errors++;
 375
 376         num_tests++;
 377         ret = test_jprobe();
 378         if (ret < 0)
 379                 errors++;
 380
 381         num_tests++;
 382         ret = test_jprobes();
 383         if (ret < 0)
 384                 errors++;
 385
 386 #ifdef CONFIG_KRETPROBES
 387         num_tests++;
 388         ret = test_kretprobe();
 389         if (ret < 0)
 390                 errors++;
 391
 392         num_tests++;
 393         ret = test_kretprobes();
 394         if (ret < 0)
 395                 errors++;
 396 #endif /* CONFIG_KRETPROBES */
 397
 398         if (errors)
 399                 printk(KERN_ERR "BUG: Kprobe smoke test: %d out of "
 400                                 "%d tests failed\n", errors, num_tests);
 401         else if (handler_errors)
 402                 printk(KERN_ERR "BUG: Kprobe smoke test: %d error(s) "
 403                                 "running handlers\n", handler_errors);
 404         else
 405                 printk(KERN_INFO "Kprobe smoke test passed successfully\n");
 406
 407         return 0;
 408 }