aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJosh Poimboeuf <jpoimboe@redhat.com>2015-02-09 12:31:13 -0500
committerJiri Kosina <jkosina@suse.cz>2015-02-18 15:06:38 -0500
commit0937e3b025f70e33f018aa55ee8d32b8731730a7 (patch)
treef8bed0ffeae83f15e02f6f60bd1d910d9791836b
parent4421f8f0fa02bc982b410cd773223cc280791c54 (diff)
livepatch: simplify disable error path
If registering the function with ftrace has previously succeeded, unregistering will almost never fail. Even if it does, it's not a fatal error. We can still carry on and disable the klp_func from being used by removing it from the klp_ops func stack. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Petr Mladek <pmladek@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
-rw-r--r--kernel/livepatch/core.c67
1 files changed, 17 insertions, 50 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index ff7f47d026ac..26df09d56f7c 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -322,32 +322,20 @@ static void notrace klp_ftrace_handler(unsigned long ip,
322 klp_arch_set_pc(regs, (unsigned long)func->new_func); 322 klp_arch_set_pc(regs, (unsigned long)func->new_func);
323} 323}
324 324
325static int klp_disable_func(struct klp_func *func) 325static void klp_disable_func(struct klp_func *func)
326{ 326{
327 struct klp_ops *ops; 327 struct klp_ops *ops;
328 int ret;
329
330 if (WARN_ON(func->state != KLP_ENABLED))
331 return -EINVAL;
332 328
333 if (WARN_ON(!func->old_addr)) 329 WARN_ON(func->state != KLP_ENABLED);
334 return -EINVAL; 330 WARN_ON(!func->old_addr);
335 331
336 ops = klp_find_ops(func->old_addr); 332 ops = klp_find_ops(func->old_addr);
337 if (WARN_ON(!ops)) 333 if (WARN_ON(!ops))
338 return -EINVAL; 334 return;
339 335
340 if (list_is_singular(&ops->func_stack)) { 336 if (list_is_singular(&ops->func_stack)) {
341 ret = unregister_ftrace_function(&ops->fops); 337 WARN_ON(unregister_ftrace_function(&ops->fops));
342 if (ret) { 338 WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
343 pr_err("failed to unregister ftrace handler for function '%s' (%d)\n",
344 func->old_name, ret);
345 return ret;
346 }
347
348 ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
349 if (ret)
350 pr_warn("function unregister succeeded but failed to clear the filter\n");
351 339
352 list_del_rcu(&func->stack_node); 340 list_del_rcu(&func->stack_node);
353 list_del(&ops->node); 341 list_del(&ops->node);
@@ -357,8 +345,6 @@ static int klp_disable_func(struct klp_func *func)
357 } 345 }
358 346
359 func->state = KLP_DISABLED; 347 func->state = KLP_DISABLED;
360
361 return 0;
362} 348}
363 349
364static int klp_enable_func(struct klp_func *func) 350static int klp_enable_func(struct klp_func *func)
@@ -419,23 +405,15 @@ err:
419 return ret; 405 return ret;
420} 406}
421 407
422static int klp_disable_object(struct klp_object *obj) 408static void klp_disable_object(struct klp_object *obj)
423{ 409{
424 struct klp_func *func; 410 struct klp_func *func;
425 int ret;
426 411
427 for (func = obj->funcs; func->old_name; func++) { 412 for (func = obj->funcs; func->old_name; func++)
428 if (func->state != KLP_ENABLED) 413 if (func->state == KLP_ENABLED)
429 continue; 414 klp_disable_func(func);
430
431 ret = klp_disable_func(func);
432 if (ret)
433 return ret;
434 }
435 415
436 obj->state = KLP_DISABLED; 416 obj->state = KLP_DISABLED;
437
438 return 0;
439} 417}
440 418
441static int klp_enable_object(struct klp_object *obj) 419static int klp_enable_object(struct klp_object *obj)
@@ -451,22 +429,19 @@ static int klp_enable_object(struct klp_object *obj)
451 429
452 for (func = obj->funcs; func->old_name; func++) { 430 for (func = obj->funcs; func->old_name; func++) {
453 ret = klp_enable_func(func); 431 ret = klp_enable_func(func);
454 if (ret) 432 if (ret) {
455 goto unregister; 433 klp_disable_object(obj);
434 return ret;
435 }
456 } 436 }
457 obj->state = KLP_ENABLED; 437 obj->state = KLP_ENABLED;
458 438
459 return 0; 439 return 0;
460
461unregister:
462 WARN_ON(klp_disable_object(obj));
463 return ret;
464} 440}
465 441
466static int __klp_disable_patch(struct klp_patch *patch) 442static int __klp_disable_patch(struct klp_patch *patch)
467{ 443{
468 struct klp_object *obj; 444 struct klp_object *obj;
469 int ret;
470 445
471 /* enforce stacking: only the last enabled patch can be disabled */ 446 /* enforce stacking: only the last enabled patch can be disabled */
472 if (!list_is_last(&patch->list, &klp_patches) && 447 if (!list_is_last(&patch->list, &klp_patches) &&
@@ -476,12 +451,8 @@ static int __klp_disable_patch(struct klp_patch *patch)
476 pr_notice("disabling patch '%s'\n", patch->mod->name); 451 pr_notice("disabling patch '%s'\n", patch->mod->name);
477 452
478 for (obj = patch->objs; obj->funcs; obj++) { 453 for (obj = patch->objs; obj->funcs; obj++) {
479 if (obj->state != KLP_ENABLED) 454 if (obj->state == KLP_ENABLED)
480 continue; 455 klp_disable_object(obj);
481
482 ret = klp_disable_object(obj);
483 if (ret)
484 return ret;
485 } 456 }
486 457
487 patch->state = KLP_DISABLED; 458 patch->state = KLP_DISABLED;
@@ -931,7 +902,6 @@ static void klp_module_notify_going(struct klp_patch *patch,
931{ 902{
932 struct module *pmod = patch->mod; 903 struct module *pmod = patch->mod;
933 struct module *mod = obj->mod; 904 struct module *mod = obj->mod;
934 int ret;
935 905
936 if (patch->state == KLP_DISABLED) 906 if (patch->state == KLP_DISABLED)
937 goto disabled; 907 goto disabled;
@@ -939,10 +909,7 @@ static void klp_module_notify_going(struct klp_patch *patch,
939 pr_notice("reverting patch '%s' on unloading module '%s'\n", 909 pr_notice("reverting patch '%s' on unloading module '%s'\n",
940 pmod->name, mod->name); 910 pmod->name, mod->name);
941 911
942 ret = klp_disable_object(obj); 912 klp_disable_object(obj);
943 if (ret)
944 pr_warn("failed to revert patch '%s' on module '%s' (%d)\n",
945 pmod->name, mod->name, ret);
946 913
947disabled: 914disabled:
948 klp_free_object_loaded(obj); 915 klp_free_object_loaded(obj);