1 // SPDX-License-Identifier: GPL-2.0
3 * Kprobes-based tracing events
5 * Created by Masami Hiramatsu <mhiramat@redhat.com>
8 #define pr_fmt(fmt) "trace_kprobe: " fmt
10 #include <linux/bpf-cgroup.h>
11 #include <linux/security.h>
12 #include <linux/module.h>
13 #include <linux/uaccess.h>
14 #include <linux/rculist.h>
15 #include <linux/error-injection.h>
17 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
19 #include "trace_dynevent.h"
20 #include "trace_kprobe_selftest.h"
21 #include "trace_probe.h"
22 #include "trace_probe_tmpl.h"
23 #include "trace_probe_kernel.h"
25 #define KPROBE_EVENT_SYSTEM "kprobes"
26 #define KRETPROBE_MAXACTIVE_MAX 4096
28 /* Kprobe early definition from command line */
29 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
31 static int __init set_kprobe_boot_events(char *str)
33 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
34 disable_tracing_selftest("running kprobe events");
38 __setup("kprobe_event=", set_kprobe_boot_events);
40 static int trace_kprobe_create(const char *raw_command);
41 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
42 static int trace_kprobe_release(struct dyn_event *ev);
43 static bool trace_kprobe_is_busy(struct dyn_event *ev);
44 static bool trace_kprobe_match(const char *system, const char *event,
45 int argc, const char **argv, struct dyn_event *ev);
47 static struct dyn_event_operations trace_kprobe_ops = {
48 .create = trace_kprobe_create,
49 .show = trace_kprobe_show,
50 .is_busy = trace_kprobe_is_busy,
51 .free = trace_kprobe_release,
52 .match = trace_kprobe_match,
56 * Kprobe event core functions
59 struct dyn_event devent;
60 struct kretprobe rp; /* Use rp.kp for kprobe use */
61 unsigned long __percpu *nhit;
62 const char *symbol; /* symbol name */
63 struct trace_probe tp;
66 static bool is_trace_kprobe(struct dyn_event *ev)
68 return ev->ops == &trace_kprobe_ops;
71 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
73 return container_of(ev, struct trace_kprobe, devent);
77 * for_each_trace_kprobe - iterate over the trace_kprobe list
78 * @pos: the struct trace_kprobe * for each entry
79 * @dpos: the struct dyn_event * to use as a loop cursor
81 #define for_each_trace_kprobe(pos, dpos) \
82 for_each_dyn_event(dpos) \
83 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
85 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
87 return tk->rp.handler != NULL;
90 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
92 return tk->symbol ? tk->symbol : "unknown";
95 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
97 return tk->rp.kp.offset;
100 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
102 return kprobe_gone(&tk->rp.kp);
105 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
108 int len = strlen(module_name(mod));
109 const char *name = trace_kprobe_symbol(tk);
111 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
121 p = strchr(tk->symbol, ':');
125 rcu_read_lock_sched();
126 ret = !!find_module(tk->symbol);
127 rcu_read_unlock_sched();
133 static bool trace_kprobe_is_busy(struct dyn_event *ev)
135 struct trace_kprobe *tk = to_trace_kprobe(ev);
137 return trace_probe_is_enabled(&tk->tp);
140 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
141 int argc, const char **argv)
143 char buf[MAX_ARGSTR_LEN + 1];
149 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
150 else if (tk->rp.kp.offset)
151 snprintf(buf, sizeof(buf), "%s+%u",
152 trace_kprobe_symbol(tk), tk->rp.kp.offset);
154 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
155 if (strcmp(buf, argv[0]))
159 return trace_probe_match_command_args(&tk->tp, argc, argv);
162 static bool trace_kprobe_match(const char *system, const char *event,
163 int argc, const char **argv, struct dyn_event *ev)
165 struct trace_kprobe *tk = to_trace_kprobe(ev);
167 return (event[0] == '\0' ||
168 strcmp(trace_probe_name(&tk->tp), event) == 0) &&
169 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
170 trace_kprobe_match_command_head(tk, argc, argv);
173 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
175 unsigned long nhit = 0;
178 for_each_possible_cpu(cpu)
179 nhit += *per_cpu_ptr(tk->nhit, cpu);
184 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
186 return !(list_empty(&tk->rp.kp.list) &&
187 hlist_unhashed(&tk->rp.kp.hlist));
190 /* Return 0 if it fails to find the symbol address */
191 static nokprobe_inline
192 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
197 addr = (unsigned long)
198 kallsyms_lookup_name(trace_kprobe_symbol(tk));
200 addr += tk->rp.kp.offset;
202 addr = (unsigned long)tk->rp.kp.addr;
207 static nokprobe_inline struct trace_kprobe *
208 trace_kprobe_primary_from_call(struct trace_event_call *call)
210 struct trace_probe *tp;
212 tp = trace_probe_primary_from_call(call);
213 if (WARN_ON_ONCE(!tp))
216 return container_of(tp, struct trace_kprobe, tp);
219 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
221 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
223 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
224 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
225 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
228 bool trace_kprobe_error_injectable(struct trace_event_call *call)
230 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
232 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
236 static int register_kprobe_event(struct trace_kprobe *tk);
237 static int unregister_kprobe_event(struct trace_kprobe *tk);
239 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
240 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
241 struct pt_regs *regs);
243 static void free_trace_kprobe(struct trace_kprobe *tk)
246 trace_probe_cleanup(&tk->tp);
248 free_percpu(tk->nhit);
254 * Allocate new trace_probe and initialize it (including kprobes).
256 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
262 int nargs, bool is_return)
264 struct trace_kprobe *tk;
267 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
271 tk->nhit = alloc_percpu(unsigned long);
276 tk->symbol = kstrdup(symbol, GFP_KERNEL);
279 tk->rp.kp.symbol_name = tk->symbol;
280 tk->rp.kp.offset = offs;
282 tk->rp.kp.addr = addr;
285 tk->rp.handler = kretprobe_dispatcher;
287 tk->rp.kp.pre_handler = kprobe_dispatcher;
289 tk->rp.maxactive = maxactive;
290 INIT_HLIST_NODE(&tk->rp.kp.hlist);
291 INIT_LIST_HEAD(&tk->rp.kp.list);
293 ret = trace_probe_init(&tk->tp, event, group, false);
297 dyn_event_init(&tk->devent, &trace_kprobe_ops);
300 free_trace_kprobe(tk);
304 static struct trace_kprobe *find_trace_kprobe(const char *event,
307 struct dyn_event *pos;
308 struct trace_kprobe *tk;
310 for_each_trace_kprobe(tk, pos)
311 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
312 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
317 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
321 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
322 if (trace_kprobe_is_return(tk))
323 ret = enable_kretprobe(&tk->rp);
325 ret = enable_kprobe(&tk->rp.kp);
331 static void __disable_trace_kprobe(struct trace_probe *tp)
333 struct trace_kprobe *tk;
335 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
336 if (!trace_kprobe_is_registered(tk))
338 if (trace_kprobe_is_return(tk))
339 disable_kretprobe(&tk->rp);
341 disable_kprobe(&tk->rp.kp);
347 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
349 static int enable_trace_kprobe(struct trace_event_call *call,
350 struct trace_event_file *file)
352 struct trace_probe *tp;
353 struct trace_kprobe *tk;
357 tp = trace_probe_primary_from_call(call);
358 if (WARN_ON_ONCE(!tp))
360 enabled = trace_probe_is_enabled(tp);
362 /* This also changes "enabled" state */
364 ret = trace_probe_add_file(tp, file);
368 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
373 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
374 if (trace_kprobe_has_gone(tk))
376 ret = __enable_trace_kprobe(tk);
383 /* Failed to enable one of them. Roll back all */
385 __disable_trace_kprobe(tp);
387 trace_probe_remove_file(tp, file);
389 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
396 * Disable trace_probe
397 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
399 static int disable_trace_kprobe(struct trace_event_call *call,
400 struct trace_event_file *file)
402 struct trace_probe *tp;
404 tp = trace_probe_primary_from_call(call);
405 if (WARN_ON_ONCE(!tp))
409 if (!trace_probe_get_file_link(tp, file))
411 if (!trace_probe_has_single_file(tp))
413 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
415 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
417 if (!trace_probe_is_enabled(tp))
418 __disable_trace_kprobe(tp);
423 * Synchronization is done in below function. For perf event,
424 * file == NULL and perf_trace_event_unreg() calls
425 * tracepoint_synchronize_unregister() to ensure synchronize
426 * event. We don't need to care about it.
428 trace_probe_remove_file(tp, file);
433 #if defined(CONFIG_DYNAMIC_FTRACE) && \
434 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
435 static bool __within_notrace_func(unsigned long addr)
437 unsigned long offset, size;
439 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
442 /* Get the entry address of the target function */
446 * Since ftrace_location_range() does inclusive range check, we need
447 * to subtract 1 byte from the end address.
449 return !ftrace_location_range(addr, addr + size - 1);
452 static bool within_notrace_func(struct trace_kprobe *tk)
454 unsigned long addr = trace_kprobe_address(tk);
455 char symname[KSYM_NAME_LEN], *p;
457 if (!__within_notrace_func(addr))
460 /* Check if the address is on a suffixed-symbol */
461 if (!lookup_symbol_name(addr, symname)) {
462 p = strchr(symname, '.');
466 addr = (unsigned long)kprobe_lookup_name(symname, 0);
468 return __within_notrace_func(addr);
474 #define within_notrace_func(tk) (false)
477 /* Internal register function - just handle k*probes and flags */
478 static int __register_trace_kprobe(struct trace_kprobe *tk)
482 ret = security_locked_down(LOCKDOWN_KPROBES);
486 if (trace_kprobe_is_registered(tk))
489 if (within_notrace_func(tk)) {
490 pr_warn("Could not probe notrace function %s\n",
491 trace_kprobe_symbol(tk));
495 for (i = 0; i < tk->tp.nr_args; i++) {
496 ret = traceprobe_update_arg(&tk->tp.args[i]);
501 /* Set/clear disabled flag according to tp->flag */
502 if (trace_probe_is_enabled(&tk->tp))
503 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
505 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
507 if (trace_kprobe_is_return(tk))
508 ret = register_kretprobe(&tk->rp);
510 ret = register_kprobe(&tk->rp.kp);
515 /* Internal unregister function - just handle k*probes and flags */
516 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
518 if (trace_kprobe_is_registered(tk)) {
519 if (trace_kprobe_is_return(tk))
520 unregister_kretprobe(&tk->rp);
522 unregister_kprobe(&tk->rp.kp);
523 /* Cleanup kprobe for reuse and mark it unregistered */
524 INIT_HLIST_NODE(&tk->rp.kp.hlist);
525 INIT_LIST_HEAD(&tk->rp.kp.list);
526 if (tk->rp.kp.symbol_name)
527 tk->rp.kp.addr = NULL;
531 /* Unregister a trace_probe and probe_event */
532 static int unregister_trace_kprobe(struct trace_kprobe *tk)
534 /* If other probes are on the event, just unregister kprobe */
535 if (trace_probe_has_sibling(&tk->tp))
538 /* Enabled event can not be unregistered */
539 if (trace_probe_is_enabled(&tk->tp))
542 /* If there's a reference to the dynamic event */
543 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
546 /* Will fail if probe is being used by ftrace or perf */
547 if (unregister_kprobe_event(tk))
551 __unregister_trace_kprobe(tk);
552 dyn_event_remove(&tk->devent);
553 trace_probe_unlink(&tk->tp);
558 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
559 struct trace_kprobe *comp)
561 struct trace_probe_event *tpe = orig->tp.event;
564 list_for_each_entry(orig, &tpe->probes, tp.list) {
565 if (strcmp(trace_kprobe_symbol(orig),
566 trace_kprobe_symbol(comp)) ||
567 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
571 * trace_probe_compare_arg_type() ensured that nr_args and
572 * each argument name and type are same. Let's compare comm.
574 for (i = 0; i < orig->tp.nr_args; i++) {
575 if (strcmp(orig->tp.args[i].comm,
576 comp->tp.args[i].comm))
580 if (i == orig->tp.nr_args)
587 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
591 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
593 /* Note that argument starts index = 2 */
594 trace_probe_log_set_index(ret + 1);
595 trace_probe_log_err(0, DIFF_ARG_TYPE);
598 if (trace_kprobe_has_same_kprobe(to, tk)) {
599 trace_probe_log_set_index(0);
600 trace_probe_log_err(0, SAME_PROBE);
604 /* Append to existing event */
605 ret = trace_probe_append(&tk->tp, &to->tp);
609 /* Register k*probe */
610 ret = __register_trace_kprobe(tk);
611 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
612 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
617 trace_probe_unlink(&tk->tp);
619 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
624 /* Register a trace_probe and probe_event */
625 static int register_trace_kprobe(struct trace_kprobe *tk)
627 struct trace_kprobe *old_tk;
630 mutex_lock(&event_mutex);
632 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
633 trace_probe_group_name(&tk->tp));
635 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
636 trace_probe_log_set_index(0);
637 trace_probe_log_err(0, DIFF_PROBE_TYPE);
640 ret = append_trace_kprobe(tk, old_tk);
645 /* Register new event */
646 ret = register_kprobe_event(tk);
648 if (ret == -EEXIST) {
649 trace_probe_log_set_index(0);
650 trace_probe_log_err(0, EVENT_EXIST);
652 pr_warn("Failed to register probe event(%d)\n", ret);
656 /* Register k*probe */
657 ret = __register_trace_kprobe(tk);
658 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
659 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
664 unregister_kprobe_event(tk);
666 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
669 mutex_unlock(&event_mutex);
673 /* Module notifier call back, checking event on the module */
674 static int trace_kprobe_module_callback(struct notifier_block *nb,
675 unsigned long val, void *data)
677 struct module *mod = data;
678 struct dyn_event *pos;
679 struct trace_kprobe *tk;
682 if (val != MODULE_STATE_COMING)
685 /* Update probes on coming module */
686 mutex_lock(&event_mutex);
687 for_each_trace_kprobe(tk, pos) {
688 if (trace_kprobe_within_module(tk, mod)) {
689 /* Don't need to check busy - this should have gone. */
690 __unregister_trace_kprobe(tk);
691 ret = __register_trace_kprobe(tk);
693 pr_warn("Failed to re-register probe %s on %s: %d\n",
694 trace_probe_name(&tk->tp),
695 module_name(mod), ret);
698 mutex_unlock(&event_mutex);
703 static struct notifier_block trace_kprobe_module_nb = {
704 .notifier_call = trace_kprobe_module_callback,
705 .priority = 1 /* Invoked after kprobe module callback */
708 static int __trace_kprobe_create(int argc, const char *argv[])
713 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
715 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
717 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
720 * $retval : fetch return value
721 * $stack : fetch stack address
722 * $stackN : fetch Nth of stack (N:0-)
723 * $comm : fetch current task comm
724 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
725 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
726 * %REG : fetch register REG
727 * Dereferencing memory fetch:
728 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
729 * Alias name of args:
730 * NAME=FETCHARG : set NAME as alias of FETCHARG.
732 * FETCHARG:TYPE : use TYPE instead of unsigned long.
734 struct trace_kprobe *tk = NULL;
735 int i, len, new_argc = 0, ret = 0;
736 bool is_return = false;
737 char *symbol = NULL, *tmp = NULL;
738 const char **new_argv = NULL;
739 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
740 enum probe_print_type ptype;
744 char buf[MAX_EVENT_NAME_LEN];
745 char gbuf[MAX_EVENT_NAME_LEN];
746 char abuf[MAX_BTF_ARGS_LEN];
747 struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
749 switch (argv[0][0]) {
761 trace_probe_log_init("trace_kprobe", argc, argv);
763 event = strchr(&argv[0][1], ':');
767 if (isdigit(argv[0][1])) {
769 trace_probe_log_err(1, BAD_MAXACT_TYPE);
773 len = event - &argv[0][1] - 1;
775 len = strlen(&argv[0][1]);
776 if (len > MAX_EVENT_NAME_LEN - 1) {
777 trace_probe_log_err(1, BAD_MAXACT);
780 memcpy(buf, &argv[0][1], len);
782 ret = kstrtouint(buf, 0, &maxactive);
783 if (ret || !maxactive) {
784 trace_probe_log_err(1, BAD_MAXACT);
787 /* kretprobes instances are iterated over via a list. The
788 * maximum should stay reasonable.
790 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
791 trace_probe_log_err(1, MAXACT_TOO_BIG);
796 /* try to parse an address. if that fails, try to read the
797 * input as a symbol. */
798 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
799 trace_probe_log_set_index(1);
800 /* Check whether uprobe event specified */
801 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
805 /* a symbol specified */
806 symbol = kstrdup(argv[1], GFP_KERNEL);
810 tmp = strchr(symbol, '%');
812 if (!strcmp(tmp, "%return")) {
816 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
821 /* TODO: support .init module functions */
822 ret = traceprobe_split_symbol_offset(symbol, &offset);
823 if (ret || offset < 0 || offset > UINT_MAX) {
824 trace_probe_log_err(0, BAD_PROBE_ADDR);
828 ctx.flags |= TPARG_FL_RETURN;
829 ret = kprobe_on_func_entry(NULL, symbol, offset);
830 if (ret == 0 && !is_return)
831 ctx.flags |= TPARG_FL_FENTRY;
832 /* Defer the ENOENT case until register kprobe */
833 if (ret == -EINVAL && is_return) {
834 trace_probe_log_err(0, BAD_RETPROBE);
839 trace_probe_log_set_index(0);
841 ret = traceprobe_parse_event_name(&event, &group, gbuf,
848 /* Make a new event name */
850 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
851 is_return ? 'r' : 'p', symbol, offset);
853 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
854 is_return ? 'r' : 'p', addr);
855 sanitize_event_name(buf);
859 argc -= 2; argv += 2;
860 ctx.funcname = symbol;
861 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
862 abuf, MAX_BTF_ARGS_LEN, &ctx);
863 if (IS_ERR(new_argv)) {
864 ret = PTR_ERR(new_argv);
874 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
878 /* This must return -ENOMEM, else there is a bug */
879 WARN_ON_ONCE(ret != -ENOMEM);
880 goto out; /* We know tk is not allocated */
883 /* parse arguments */
884 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
885 trace_probe_log_set_index(i + 2);
887 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
889 goto error; /* This can be -ENOMEM */
892 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
893 ret = traceprobe_set_print_fmt(&tk->tp, ptype);
897 ret = register_trace_kprobe(tk);
899 trace_probe_log_set_index(1);
901 trace_probe_log_err(0, BAD_INSN_BNDRY);
902 else if (ret == -ENOENT)
903 trace_probe_log_err(0, BAD_PROBE_ADDR);
904 else if (ret != -ENOMEM && ret != -EEXIST)
905 trace_probe_log_err(0, FAIL_REG_PROBE);
910 traceprobe_finish_parse(&ctx);
911 trace_probe_log_clear();
919 free_trace_kprobe(tk);
923 static int trace_kprobe_create(const char *raw_command)
925 return trace_probe_create(raw_command, __trace_kprobe_create);
928 static int create_or_delete_trace_kprobe(const char *raw_command)
932 if (raw_command[0] == '-')
933 return dyn_event_release(raw_command, &trace_kprobe_ops);
935 ret = trace_kprobe_create(raw_command);
936 return ret == -ECANCELED ? -EINVAL : ret;
939 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
941 return create_or_delete_trace_kprobe(cmd->seq.buffer);
945 * kprobe_event_cmd_init - Initialize a kprobe event command object
946 * @cmd: A pointer to the dynevent_cmd struct representing the new event
947 * @buf: A pointer to the buffer used to build the command
948 * @maxlen: The length of the buffer passed in @buf
950 * Initialize a synthetic event command object. Use this before
951 * calling any of the other kprobe_event functions.
953 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
955 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
956 trace_kprobe_run_command);
958 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
961 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
962 * @cmd: A pointer to the dynevent_cmd struct representing the new event
963 * @name: The name of the kprobe event
964 * @loc: The location of the kprobe event
965 * @kretprobe: Is this a return probe?
966 * @args: Variable number of arg (pairs), one pair for each field
968 * NOTE: Users normally won't want to call this function directly, but
969 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
970 * adds a NULL to the end of the arg list. If this function is used
971 * directly, make sure the last arg in the variable arg list is NULL.
973 * Generate a kprobe event command to be executed by
974 * kprobe_event_gen_cmd_end(). This function can be used to generate the
975 * complete command or only the first part of it; in the latter case,
976 * kprobe_event_add_fields() can be used to add more fields following this.
978 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
979 * returns -EINVAL if @loc == NULL.
981 * Return: 0 if successful, error otherwise.
983 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
984 const char *name, const char *loc, ...)
986 char buf[MAX_EVENT_NAME_LEN];
987 struct dynevent_arg arg;
991 if (cmd->type != DYNEVENT_TYPE_KPROBE)
998 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1000 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1002 ret = dynevent_str_add(cmd, buf);
1006 dynevent_arg_init(&arg, 0);
1008 ret = dynevent_arg_add(cmd, &arg, NULL);
1012 va_start(args, loc);
1016 field = va_arg(args, const char *);
1020 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1026 ret = dynevent_arg_add(cmd, &arg, NULL);
1034 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1037 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1038 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1039 * @args: Variable number of arg (pairs), one pair for each field
1041 * NOTE: Users normally won't want to call this function directly, but
1042 * rather use the kprobe_event_add_fields() wrapper, which
1043 * automatically adds a NULL to the end of the arg list. If this
1044 * function is used directly, make sure the last arg in the variable
1047 * Add probe fields to an existing kprobe command using a variable
1048 * list of args. Fields are added in the same order they're listed.
1050 * Return: 0 if successful, error otherwise.
1052 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1054 struct dynevent_arg arg;
1058 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1061 dynevent_arg_init(&arg, 0);
1063 va_start(args, cmd);
1067 field = va_arg(args, const char *);
1071 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1077 ret = dynevent_arg_add(cmd, &arg, NULL);
1085 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1088 * kprobe_event_delete - Delete a kprobe event
1089 * @name: The name of the kprobe event to delete
1091 * Delete a kprobe event with the give @name from kernel code rather
1092 * than directly from the command line.
1094 * Return: 0 if successful, error otherwise.
1096 int kprobe_event_delete(const char *name)
1098 char buf[MAX_EVENT_NAME_LEN];
1100 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1102 return create_or_delete_trace_kprobe(buf);
1104 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1106 static int trace_kprobe_release(struct dyn_event *ev)
1108 struct trace_kprobe *tk = to_trace_kprobe(ev);
1109 int ret = unregister_trace_kprobe(tk);
1112 free_trace_kprobe(tk);
1116 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1118 struct trace_kprobe *tk = to_trace_kprobe(ev);
1121 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1122 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1123 seq_printf(m, "%d", tk->rp.maxactive);
1124 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1125 trace_probe_name(&tk->tp));
1128 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1129 else if (tk->rp.kp.offset)
1130 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1133 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1135 for (i = 0; i < tk->tp.nr_args; i++)
1136 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1142 static int probes_seq_show(struct seq_file *m, void *v)
1144 struct dyn_event *ev = v;
1146 if (!is_trace_kprobe(ev))
1149 return trace_kprobe_show(m, ev);
1152 static const struct seq_operations probes_seq_op = {
1153 .start = dyn_event_seq_start,
1154 .next = dyn_event_seq_next,
1155 .stop = dyn_event_seq_stop,
1156 .show = probes_seq_show
1159 static int probes_open(struct inode *inode, struct file *file)
1163 ret = security_locked_down(LOCKDOWN_TRACEFS);
1167 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1168 ret = dyn_events_release_all(&trace_kprobe_ops);
1173 return seq_open(file, &probes_seq_op);
1176 static ssize_t probes_write(struct file *file, const char __user *buffer,
1177 size_t count, loff_t *ppos)
1179 return trace_parse_run_command(file, buffer, count, ppos,
1180 create_or_delete_trace_kprobe);
1183 static const struct file_operations kprobe_events_ops = {
1184 .owner = THIS_MODULE,
1185 .open = probes_open,
1187 .llseek = seq_lseek,
1188 .release = seq_release,
1189 .write = probes_write,
1192 /* Probes profiling interfaces */
1193 static int probes_profile_seq_show(struct seq_file *m, void *v)
1195 struct dyn_event *ev = v;
1196 struct trace_kprobe *tk;
1197 unsigned long nmissed;
1199 if (!is_trace_kprobe(ev))
1202 tk = to_trace_kprobe(ev);
1203 nmissed = trace_kprobe_is_return(tk) ?
1204 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1205 seq_printf(m, " %-44s %15lu %15lu\n",
1206 trace_probe_name(&tk->tp),
1207 trace_kprobe_nhit(tk),
1213 static const struct seq_operations profile_seq_op = {
1214 .start = dyn_event_seq_start,
1215 .next = dyn_event_seq_next,
1216 .stop = dyn_event_seq_stop,
1217 .show = probes_profile_seq_show
1220 static int profile_open(struct inode *inode, struct file *file)
1224 ret = security_locked_down(LOCKDOWN_TRACEFS);
1228 return seq_open(file, &profile_seq_op);
1231 static const struct file_operations kprobe_profile_ops = {
1232 .owner = THIS_MODULE,
1233 .open = profile_open,
1235 .llseek = seq_lseek,
1236 .release = seq_release,
1239 /* Note that we don't verify it, since the code does not come from user space */
1241 process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
1244 struct pt_regs *regs = rec;
1249 /* 1st stage: get value from context */
1252 val = regs_get_register(regs, code->param);
1254 case FETCH_OP_STACK:
1255 val = regs_get_kernel_stack_nth(regs, code->param);
1257 case FETCH_OP_STACKP:
1258 val = kernel_stack_pointer(regs);
1260 case FETCH_OP_RETVAL:
1261 val = regs_return_value(regs);
1263 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1265 val = regs_get_kernel_argument(regs, code->param);
1268 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1272 ret = process_common_fetch_insn(code, &val);
1278 return process_fetch_insn_bottom(code, val, dest, base);
1280 NOKPROBE_SYMBOL(process_fetch_insn)
1282 /* Kprobe handler */
1283 static nokprobe_inline void
1284 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1285 struct trace_event_file *trace_file)
1287 struct kprobe_trace_entry_head *entry;
1288 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1289 struct trace_event_buffer fbuffer;
1292 WARN_ON(call != trace_file->event_call);
1294 if (trace_trigger_soft_disabled(trace_file))
1297 dsize = __get_data_size(&tk->tp, regs);
1299 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1300 sizeof(*entry) + tk->tp.size + dsize);
1304 fbuffer.regs = regs;
1305 entry->ip = (unsigned long)tk->rp.kp.addr;
1306 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1308 trace_event_buffer_commit(&fbuffer);
1312 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1314 struct event_file_link *link;
1316 trace_probe_for_each_link_rcu(link, &tk->tp)
1317 __kprobe_trace_func(tk, regs, link->file);
1319 NOKPROBE_SYMBOL(kprobe_trace_func);
1321 /* Kretprobe handler */
1322 static nokprobe_inline void
1323 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1324 struct pt_regs *regs,
1325 struct trace_event_file *trace_file)
1327 struct kretprobe_trace_entry_head *entry;
1328 struct trace_event_buffer fbuffer;
1329 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1332 WARN_ON(call != trace_file->event_call);
1334 if (trace_trigger_soft_disabled(trace_file))
1337 dsize = __get_data_size(&tk->tp, regs);
1339 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1340 sizeof(*entry) + tk->tp.size + dsize);
1344 fbuffer.regs = regs;
1345 entry->func = (unsigned long)tk->rp.kp.addr;
1346 entry->ret_ip = get_kretprobe_retaddr(ri);
1347 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1349 trace_event_buffer_commit(&fbuffer);
1353 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1354 struct pt_regs *regs)
1356 struct event_file_link *link;
1358 trace_probe_for_each_link_rcu(link, &tk->tp)
1359 __kretprobe_trace_func(tk, ri, regs, link->file);
1361 NOKPROBE_SYMBOL(kretprobe_trace_func);
1363 /* Event entry printers */
1364 static enum print_line_t
1365 print_kprobe_event(struct trace_iterator *iter, int flags,
1366 struct trace_event *event)
1368 struct kprobe_trace_entry_head *field;
1369 struct trace_seq *s = &iter->seq;
1370 struct trace_probe *tp;
1372 field = (struct kprobe_trace_entry_head *)iter->ent;
1373 tp = trace_probe_primary_from_call(
1374 container_of(event, struct trace_event_call, event));
1375 if (WARN_ON_ONCE(!tp))
1378 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1380 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1383 trace_seq_putc(s, ')');
1385 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1386 (u8 *)&field[1], field) < 0)
1389 trace_seq_putc(s, '\n');
1391 return trace_handle_return(s);
1394 static enum print_line_t
1395 print_kretprobe_event(struct trace_iterator *iter, int flags,
1396 struct trace_event *event)
1398 struct kretprobe_trace_entry_head *field;
1399 struct trace_seq *s = &iter->seq;
1400 struct trace_probe *tp;
1402 field = (struct kretprobe_trace_entry_head *)iter->ent;
1403 tp = trace_probe_primary_from_call(
1404 container_of(event, struct trace_event_call, event));
1405 if (WARN_ON_ONCE(!tp))
1408 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1410 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1413 trace_seq_puts(s, " <- ");
1415 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1418 trace_seq_putc(s, ')');
1420 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1421 (u8 *)&field[1], field) < 0)
1424 trace_seq_putc(s, '\n');
1427 return trace_handle_return(s);
1431 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1434 struct kprobe_trace_entry_head field;
1435 struct trace_probe *tp;
1437 tp = trace_probe_primary_from_call(event_call);
1438 if (WARN_ON_ONCE(!tp))
1441 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1443 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1446 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1449 struct kretprobe_trace_entry_head field;
1450 struct trace_probe *tp;
1452 tp = trace_probe_primary_from_call(event_call);
1453 if (WARN_ON_ONCE(!tp))
1456 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1457 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1459 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1462 #ifdef CONFIG_PERF_EVENTS
1464 /* Kprobe profile handler */
1466 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1468 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1469 struct kprobe_trace_entry_head *entry;
1470 struct hlist_head *head;
1471 int size, __size, dsize;
1474 if (bpf_prog_array_valid(call)) {
1475 unsigned long orig_ip = instruction_pointer(regs);
1478 ret = trace_call_bpf(call, regs);
1481 * We need to check and see if we modified the pc of the
1482 * pt_regs, and if so return 1 so that we don't do the
1485 if (orig_ip != instruction_pointer(regs))
1491 head = this_cpu_ptr(call->perf_events);
1492 if (hlist_empty(head))
1495 dsize = __get_data_size(&tk->tp, regs);
1496 __size = sizeof(*entry) + tk->tp.size + dsize;
1497 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1498 size -= sizeof(u32);
1500 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1504 entry->ip = (unsigned long)tk->rp.kp.addr;
1505 memset(&entry[1], 0, dsize);
1506 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1507 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1511 NOKPROBE_SYMBOL(kprobe_perf_func);
1513 /* Kretprobe profile handler */
1515 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1516 struct pt_regs *regs)
1518 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1519 struct kretprobe_trace_entry_head *entry;
1520 struct hlist_head *head;
1521 int size, __size, dsize;
1524 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1527 head = this_cpu_ptr(call->perf_events);
1528 if (hlist_empty(head))
1531 dsize = __get_data_size(&tk->tp, regs);
1532 __size = sizeof(*entry) + tk->tp.size + dsize;
1533 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1534 size -= sizeof(u32);
1536 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1540 entry->func = (unsigned long)tk->rp.kp.addr;
1541 entry->ret_ip = get_kretprobe_retaddr(ri);
1542 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1543 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1546 NOKPROBE_SYMBOL(kretprobe_perf_func);
1548 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1549 const char **symbol, u64 *probe_offset,
1550 u64 *probe_addr, bool perf_type_tracepoint)
1552 const char *pevent = trace_event_name(event->tp_event);
1553 const char *group = event->tp_event->class->system;
1554 struct trace_kprobe *tk;
1556 if (perf_type_tracepoint)
1557 tk = find_trace_kprobe(pevent, group);
1559 tk = trace_kprobe_primary_from_call(event->tp_event);
1563 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1564 : BPF_FD_TYPE_KPROBE;
1565 *probe_offset = tk->rp.kp.offset;
1566 *probe_addr = kallsyms_show_value(current_cred()) ?
1567 (unsigned long)tk->rp.kp.addr : 0;
1568 *symbol = tk->symbol;
1571 #endif /* CONFIG_PERF_EVENTS */
1574 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1576 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1577 * lockless, but we can't race with this __init function.
1579 static int kprobe_register(struct trace_event_call *event,
1580 enum trace_reg type, void *data)
1582 struct trace_event_file *file = data;
1585 case TRACE_REG_REGISTER:
1586 return enable_trace_kprobe(event, file);
1587 case TRACE_REG_UNREGISTER:
1588 return disable_trace_kprobe(event, file);
1590 #ifdef CONFIG_PERF_EVENTS
1591 case TRACE_REG_PERF_REGISTER:
1592 return enable_trace_kprobe(event, NULL);
1593 case TRACE_REG_PERF_UNREGISTER:
1594 return disable_trace_kprobe(event, NULL);
1595 case TRACE_REG_PERF_OPEN:
1596 case TRACE_REG_PERF_CLOSE:
1597 case TRACE_REG_PERF_ADD:
1598 case TRACE_REG_PERF_DEL:
1605 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1607 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1610 raw_cpu_inc(*tk->nhit);
1612 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1613 kprobe_trace_func(tk, regs);
1614 #ifdef CONFIG_PERF_EVENTS
1615 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1616 ret = kprobe_perf_func(tk, regs);
1620 NOKPROBE_SYMBOL(kprobe_dispatcher);
1623 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1625 struct kretprobe *rp = get_kretprobe(ri);
1626 struct trace_kprobe *tk;
1629 * There is a small chance that get_kretprobe(ri) returns NULL when
1630 * the kretprobe is unregister on another CPU between kretprobe's
1631 * trampoline_handler and this function.
1636 tk = container_of(rp, struct trace_kprobe, rp);
1637 raw_cpu_inc(*tk->nhit);
1639 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1640 kretprobe_trace_func(tk, ri, regs);
1641 #ifdef CONFIG_PERF_EVENTS
1642 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1643 kretprobe_perf_func(tk, ri, regs);
1645 return 0; /* We don't tweak kernel, so just return 0 */
1647 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1649 static struct trace_event_functions kretprobe_funcs = {
1650 .trace = print_kretprobe_event
1653 static struct trace_event_functions kprobe_funcs = {
1654 .trace = print_kprobe_event
1657 static struct trace_event_fields kretprobe_fields_array[] = {
1658 { .type = TRACE_FUNCTION_TYPE,
1659 .define_fields = kretprobe_event_define_fields },
1663 static struct trace_event_fields kprobe_fields_array[] = {
1664 { .type = TRACE_FUNCTION_TYPE,
1665 .define_fields = kprobe_event_define_fields },
1669 static inline void init_trace_event_call(struct trace_kprobe *tk)
1671 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1673 if (trace_kprobe_is_return(tk)) {
1674 call->event.funcs = &kretprobe_funcs;
1675 call->class->fields_array = kretprobe_fields_array;
1677 call->event.funcs = &kprobe_funcs;
1678 call->class->fields_array = kprobe_fields_array;
1681 call->flags = TRACE_EVENT_FL_KPROBE;
1682 call->class->reg = kprobe_register;
1685 static int register_kprobe_event(struct trace_kprobe *tk)
1687 init_trace_event_call(tk);
1689 return trace_probe_register_event_call(&tk->tp);
1692 static int unregister_kprobe_event(struct trace_kprobe *tk)
1694 return trace_probe_unregister_event_call(&tk->tp);
1697 #ifdef CONFIG_PERF_EVENTS
1698 /* create a trace_kprobe, but don't add it to global lists */
1699 struct trace_event_call *
1700 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1703 enum probe_print_type ptype;
1704 struct trace_kprobe *tk;
1709 * local trace_kprobes are not added to dyn_event, so they are never
1710 * searched in find_trace_kprobe(). Therefore, there is no concern of
1711 * duplicated name here.
1713 event = func ? func : "DUMMY_EVENT";
1715 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1716 offs, 0 /* maxactive */, 0 /* nargs */,
1720 pr_info("Failed to allocate trace_probe.(%d)\n",
1722 return ERR_CAST(tk);
1725 init_trace_event_call(tk);
1727 ptype = trace_kprobe_is_return(tk) ?
1728 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1729 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1734 ret = __register_trace_kprobe(tk);
1738 return trace_probe_event_call(&tk->tp);
1740 free_trace_kprobe(tk);
1741 return ERR_PTR(ret);
1744 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1746 struct trace_kprobe *tk;
1748 tk = trace_kprobe_primary_from_call(event_call);
1752 if (trace_probe_is_enabled(&tk->tp)) {
1757 __unregister_trace_kprobe(tk);
1759 free_trace_kprobe(tk);
1761 #endif /* CONFIG_PERF_EVENTS */
1763 static __init void enable_boot_kprobe_events(void)
1765 struct trace_array *tr = top_trace_array();
1766 struct trace_event_file *file;
1767 struct trace_kprobe *tk;
1768 struct dyn_event *pos;
1770 mutex_lock(&event_mutex);
1771 for_each_trace_kprobe(tk, pos) {
1772 list_for_each_entry(file, &tr->events, list)
1773 if (file->event_call == trace_probe_event_call(&tk->tp))
1774 trace_event_enable_disable(file, 1, 0);
1776 mutex_unlock(&event_mutex);
1779 static __init void setup_boot_kprobe_events(void)
1781 char *p, *cmd = kprobe_boot_events_buf;
1784 strreplace(kprobe_boot_events_buf, ',', ' ');
1786 while (cmd && *cmd != '\0') {
1787 p = strchr(cmd, ';');
1791 ret = create_or_delete_trace_kprobe(cmd);
1793 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1798 enable_boot_kprobe_events();
1802 * Register dynevent at core_initcall. This allows kernel to setup kprobe
1803 * events in postcore_initcall without tracefs.
1805 static __init int init_kprobe_trace_early(void)
1809 ret = dyn_event_register(&trace_kprobe_ops);
1813 if (register_module_notifier(&trace_kprobe_module_nb))
1818 core_initcall(init_kprobe_trace_early);
1820 /* Make a tracefs interface for controlling probe points */
1821 static __init int init_kprobe_trace(void)
1825 ret = tracing_init_dentry();
1829 /* Event list interface */
1830 trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1831 NULL, NULL, &kprobe_events_ops);
1833 /* Profile interface */
1834 trace_create_file("kprobe_profile", TRACE_MODE_READ,
1835 NULL, NULL, &kprobe_profile_ops);
1837 setup_boot_kprobe_events();
1841 fs_initcall(init_kprobe_trace);
1844 #ifdef CONFIG_FTRACE_STARTUP_TEST
1845 static __init struct trace_event_file *
1846 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1848 struct trace_event_file *file;
1850 list_for_each_entry(file, &tr->events, list)
1851 if (file->event_call == trace_probe_event_call(&tk->tp))
1858 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1859 * stage, we can do this lockless.
1861 static __init int kprobe_trace_self_tests_init(void)
1864 int (*target)(int, int, int, int, int, int);
1865 struct trace_kprobe *tk;
1866 struct trace_event_file *file;
1868 if (tracing_is_disabled())
1871 if (tracing_selftest_disabled)
1874 target = kprobe_trace_selftest_target;
1876 pr_info("Testing kprobe tracing: ");
1878 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1879 if (WARN_ON_ONCE(ret)) {
1880 pr_warn("error on probing function entry.\n");
1883 /* Enable trace point */
1884 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1885 if (WARN_ON_ONCE(tk == NULL)) {
1886 pr_warn("error on getting new probe.\n");
1889 file = find_trace_probe_file(tk, top_trace_array());
1890 if (WARN_ON_ONCE(file == NULL)) {
1891 pr_warn("error on getting probe file.\n");
1894 enable_trace_kprobe(
1895 trace_probe_event_call(&tk->tp), file);
1899 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
1900 if (WARN_ON_ONCE(ret)) {
1901 pr_warn("error on probing function return.\n");
1904 /* Enable trace point */
1905 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1906 if (WARN_ON_ONCE(tk == NULL)) {
1907 pr_warn("error on getting 2nd new probe.\n");
1910 file = find_trace_probe_file(tk, top_trace_array());
1911 if (WARN_ON_ONCE(file == NULL)) {
1912 pr_warn("error on getting probe file.\n");
1915 enable_trace_kprobe(
1916 trace_probe_event_call(&tk->tp), file);
1923 ret = target(1, 2, 3, 4, 5, 6);
1926 * Not expecting an error here, the check is only to prevent the
1927 * optimizer from removing the call to target() as otherwise there
1928 * are no side-effects and the call is never performed.
1933 /* Disable trace points before removing it */
1934 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1935 if (WARN_ON_ONCE(tk == NULL)) {
1936 pr_warn("error on getting test probe.\n");
1939 if (trace_kprobe_nhit(tk) != 1) {
1940 pr_warn("incorrect number of testprobe hits\n");
1944 file = find_trace_probe_file(tk, top_trace_array());
1945 if (WARN_ON_ONCE(file == NULL)) {
1946 pr_warn("error on getting probe file.\n");
1949 disable_trace_kprobe(
1950 trace_probe_event_call(&tk->tp), file);
1953 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1954 if (WARN_ON_ONCE(tk == NULL)) {
1955 pr_warn("error on getting 2nd test probe.\n");
1958 if (trace_kprobe_nhit(tk) != 1) {
1959 pr_warn("incorrect number of testprobe2 hits\n");
1963 file = find_trace_probe_file(tk, top_trace_array());
1964 if (WARN_ON_ONCE(file == NULL)) {
1965 pr_warn("error on getting probe file.\n");
1968 disable_trace_kprobe(
1969 trace_probe_event_call(&tk->tp), file);
1972 ret = create_or_delete_trace_kprobe("-:testprobe");
1973 if (WARN_ON_ONCE(ret)) {
1974 pr_warn("error on deleting a probe.\n");
1978 ret = create_or_delete_trace_kprobe("-:testprobe2");
1979 if (WARN_ON_ONCE(ret)) {
1980 pr_warn("error on deleting a probe.\n");
1985 ret = dyn_events_release_all(&trace_kprobe_ops);
1986 if (WARN_ON_ONCE(ret)) {
1987 pr_warn("error on cleaning up probes.\n");
1991 * Wait for the optimizer work to finish. Otherwise it might fiddle
1992 * with probes in already freed __init text.
1994 wait_for_kprobe_optimizer();
1996 pr_cont("NG: Some tests are failed. Please check them.\n");
2002 late_initcall(kprobe_trace_self_tests_init);