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/security.h>
11 #include <linux/module.h>
12 #include <linux/uaccess.h>
13 #include <linux/rculist.h>
14 #include <linux/error-injection.h>
16 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
18 #include "trace_dynevent.h"
19 #include "trace_kprobe_selftest.h"
20 #include "trace_probe.h"
21 #include "trace_probe_tmpl.h"
23 #define KPROBE_EVENT_SYSTEM "kprobes"
24 #define KRETPROBE_MAXACTIVE_MAX 4096
26 /* Kprobe early definition from command line */
27 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
28 static bool kprobe_boot_events_enabled __initdata;
30 static int __init set_kprobe_boot_events(char *str)
32 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
35 __setup("kprobe_event=", set_kprobe_boot_events);
37 static int trace_kprobe_create(int argc, const char **argv);
38 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
39 static int trace_kprobe_release(struct dyn_event *ev);
40 static bool trace_kprobe_is_busy(struct dyn_event *ev);
41 static bool trace_kprobe_match(const char *system, const char *event,
42 int argc, const char **argv, struct dyn_event *ev);
44 static struct dyn_event_operations trace_kprobe_ops = {
45 .create = trace_kprobe_create,
46 .show = trace_kprobe_show,
47 .is_busy = trace_kprobe_is_busy,
48 .free = trace_kprobe_release,
49 .match = trace_kprobe_match,
53 * Kprobe event core functions
56 struct dyn_event devent;
57 struct kretprobe rp; /* Use rp.kp for kprobe use */
58 unsigned long __percpu *nhit;
59 const char *symbol; /* symbol name */
60 struct trace_probe tp;
63 static bool is_trace_kprobe(struct dyn_event *ev)
65 return ev->ops == &trace_kprobe_ops;
68 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
70 return container_of(ev, struct trace_kprobe, devent);
74 * for_each_trace_kprobe - iterate over the trace_kprobe list
75 * @pos: the struct trace_kprobe * for each entry
76 * @dpos: the struct dyn_event * to use as a loop cursor
78 #define for_each_trace_kprobe(pos, dpos) \
79 for_each_dyn_event(dpos) \
80 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
82 #define SIZEOF_TRACE_KPROBE(n) \
83 (offsetof(struct trace_kprobe, tp.args) + \
84 (sizeof(struct probe_arg) * (n)))
86 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
88 return tk->rp.handler != NULL;
91 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
93 return tk->symbol ? tk->symbol : "unknown";
96 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
98 return tk->rp.kp.offset;
101 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
103 return !!(kprobe_gone(&tk->rp.kp));
106 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
109 int len = strlen(mod->name);
110 const char *name = trace_kprobe_symbol(tk);
111 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
121 p = strchr(tk->symbol, ':');
125 mutex_lock(&module_mutex);
126 ret = !!find_module(tk->symbol);
127 mutex_unlock(&module_mutex);
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 strcmp(trace_probe_name(&tk->tp), event) == 0 &&
168 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
169 trace_kprobe_match_command_head(tk, argc, argv);
172 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
174 unsigned long nhit = 0;
177 for_each_possible_cpu(cpu)
178 nhit += *per_cpu_ptr(tk->nhit, cpu);
183 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
185 return !(list_empty(&tk->rp.kp.list) &&
186 hlist_unhashed(&tk->rp.kp.hlist));
189 /* Return 0 if it fails to find the symbol address */
190 static nokprobe_inline
191 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
196 addr = (unsigned long)
197 kallsyms_lookup_name(trace_kprobe_symbol(tk));
199 addr += tk->rp.kp.offset;
201 addr = (unsigned long)tk->rp.kp.addr;
206 static nokprobe_inline struct trace_kprobe *
207 trace_kprobe_primary_from_call(struct trace_event_call *call)
209 struct trace_probe *tp;
211 tp = trace_probe_primary_from_call(call);
212 if (WARN_ON_ONCE(!tp))
215 return container_of(tp, struct trace_kprobe, tp);
218 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
220 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
222 return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
223 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
224 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
227 bool trace_kprobe_error_injectable(struct trace_event_call *call)
229 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
231 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
235 static int register_kprobe_event(struct trace_kprobe *tk);
236 static int unregister_kprobe_event(struct trace_kprobe *tk);
238 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
239 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
240 struct pt_regs *regs);
242 static void free_trace_kprobe(struct trace_kprobe *tk)
245 trace_probe_cleanup(&tk->tp);
247 free_percpu(tk->nhit);
253 * Allocate new trace_probe and initialize it (including kprobes).
255 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
261 int nargs, bool is_return)
263 struct trace_kprobe *tk;
266 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
270 tk->nhit = alloc_percpu(unsigned long);
275 tk->symbol = kstrdup(symbol, GFP_KERNEL);
278 tk->rp.kp.symbol_name = tk->symbol;
279 tk->rp.kp.offset = offs;
281 tk->rp.kp.addr = addr;
284 tk->rp.handler = kretprobe_dispatcher;
286 tk->rp.kp.pre_handler = kprobe_dispatcher;
288 tk->rp.maxactive = maxactive;
289 INIT_HLIST_NODE(&tk->rp.kp.hlist);
290 INIT_LIST_HEAD(&tk->rp.kp.list);
292 ret = trace_probe_init(&tk->tp, event, group, false);
296 dyn_event_init(&tk->devent, &trace_kprobe_ops);
299 free_trace_kprobe(tk);
303 static struct trace_kprobe *find_trace_kprobe(const char *event,
306 struct dyn_event *pos;
307 struct trace_kprobe *tk;
309 for_each_trace_kprobe(tk, pos)
310 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
311 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
316 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
320 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
321 if (trace_kprobe_is_return(tk))
322 ret = enable_kretprobe(&tk->rp);
324 ret = enable_kprobe(&tk->rp.kp);
330 static void __disable_trace_kprobe(struct trace_probe *tp)
332 struct trace_probe *pos;
333 struct trace_kprobe *tk;
335 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
336 tk = container_of(pos, struct trace_kprobe, tp);
337 if (!trace_kprobe_is_registered(tk))
339 if (trace_kprobe_is_return(tk))
340 disable_kretprobe(&tk->rp);
342 disable_kprobe(&tk->rp.kp);
348 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
350 static int enable_trace_kprobe(struct trace_event_call *call,
351 struct trace_event_file *file)
353 struct trace_probe *pos, *tp;
354 struct trace_kprobe *tk;
358 tp = trace_probe_primary_from_call(call);
359 if (WARN_ON_ONCE(!tp))
361 enabled = trace_probe_is_enabled(tp);
363 /* This also changes "enabled" state */
365 ret = trace_probe_add_file(tp, file);
369 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
374 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
375 tk = container_of(pos, struct trace_kprobe, tp);
376 if (trace_kprobe_has_gone(tk))
378 ret = __enable_trace_kprobe(tk);
385 /* Failed to enable one of them. Roll back all */
387 __disable_trace_kprobe(tp);
389 trace_probe_remove_file(tp, file);
391 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
398 * Disable trace_probe
399 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
401 static int disable_trace_kprobe(struct trace_event_call *call,
402 struct trace_event_file *file)
404 struct trace_probe *tp;
406 tp = trace_probe_primary_from_call(call);
407 if (WARN_ON_ONCE(!tp))
411 if (!trace_probe_get_file_link(tp, file))
413 if (!trace_probe_has_single_file(tp))
415 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
417 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
419 if (!trace_probe_is_enabled(tp))
420 __disable_trace_kprobe(tp);
425 * Synchronization is done in below function. For perf event,
426 * file == NULL and perf_trace_event_unreg() calls
427 * tracepoint_synchronize_unregister() to ensure synchronize
428 * event. We don't need to care about it.
430 trace_probe_remove_file(tp, file);
435 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
436 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
437 static bool __within_notrace_func(unsigned long addr)
439 unsigned long offset, size;
441 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
444 /* Get the entry address of the target function */
448 * Since ftrace_location_range() does inclusive range check, we need
449 * to subtract 1 byte from the end address.
451 return !ftrace_location_range(addr, addr + size - 1);
454 static bool within_notrace_func(struct trace_kprobe *tk)
456 unsigned long addr = addr = trace_kprobe_address(tk);
457 char symname[KSYM_NAME_LEN], *p;
459 if (!__within_notrace_func(addr))
462 /* Check if the address is on a suffixed-symbol */
463 if (!lookup_symbol_name(addr, symname)) {
464 p = strchr(symname, '.');
468 addr = (unsigned long)kprobe_lookup_name(symname, 0);
470 return __within_notrace_func(addr);
476 #define within_notrace_func(tk) (false)
479 /* Internal register function - just handle k*probes and flags */
480 static int __register_trace_kprobe(struct trace_kprobe *tk)
484 ret = security_locked_down(LOCKDOWN_KPROBES);
488 if (trace_kprobe_is_registered(tk))
491 if (within_notrace_func(tk)) {
492 pr_warn("Could not probe notrace function %s\n",
493 trace_kprobe_symbol(tk));
497 for (i = 0; i < tk->tp.nr_args; i++) {
498 ret = traceprobe_update_arg(&tk->tp.args[i]);
503 /* Set/clear disabled flag according to tp->flag */
504 if (trace_probe_is_enabled(&tk->tp))
505 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
507 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
509 if (trace_kprobe_is_return(tk))
510 ret = register_kretprobe(&tk->rp);
512 ret = register_kprobe(&tk->rp.kp);
517 /* Internal unregister function - just handle k*probes and flags */
518 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
520 if (trace_kprobe_is_registered(tk)) {
521 if (trace_kprobe_is_return(tk))
522 unregister_kretprobe(&tk->rp);
524 unregister_kprobe(&tk->rp.kp);
525 /* Cleanup kprobe for reuse and mark it unregistered */
526 INIT_HLIST_NODE(&tk->rp.kp.hlist);
527 INIT_LIST_HEAD(&tk->rp.kp.list);
528 if (tk->rp.kp.symbol_name)
529 tk->rp.kp.addr = NULL;
533 /* Unregister a trace_probe and probe_event */
534 static int unregister_trace_kprobe(struct trace_kprobe *tk)
536 /* If other probes are on the event, just unregister kprobe */
537 if (trace_probe_has_sibling(&tk->tp))
540 /* Enabled event can not be unregistered */
541 if (trace_probe_is_enabled(&tk->tp))
544 /* Will fail if probe is being used by ftrace or perf */
545 if (unregister_kprobe_event(tk))
549 __unregister_trace_kprobe(tk);
550 dyn_event_remove(&tk->devent);
551 trace_probe_unlink(&tk->tp);
556 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
557 struct trace_kprobe *comp)
559 struct trace_probe_event *tpe = orig->tp.event;
560 struct trace_probe *pos;
563 list_for_each_entry(pos, &tpe->probes, list) {
564 orig = container_of(pos, struct trace_kprobe, tp);
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);
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 pr_warn("Failed to register probe event(%d)\n", ret);
652 /* Register k*probe */
653 ret = __register_trace_kprobe(tk);
654 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
655 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
660 unregister_kprobe_event(tk);
662 dyn_event_add(&tk->devent);
665 mutex_unlock(&event_mutex);
669 /* Module notifier call back, checking event on the module */
670 static int trace_kprobe_module_callback(struct notifier_block *nb,
671 unsigned long val, void *data)
673 struct module *mod = data;
674 struct dyn_event *pos;
675 struct trace_kprobe *tk;
678 if (val != MODULE_STATE_COMING)
681 /* Update probes on coming module */
682 mutex_lock(&event_mutex);
683 for_each_trace_kprobe(tk, pos) {
684 if (trace_kprobe_within_module(tk, mod)) {
685 /* Don't need to check busy - this should have gone. */
686 __unregister_trace_kprobe(tk);
687 ret = __register_trace_kprobe(tk);
689 pr_warn("Failed to re-register probe %s on %s: %d\n",
690 trace_probe_name(&tk->tp),
694 mutex_unlock(&event_mutex);
699 static struct notifier_block trace_kprobe_module_nb = {
700 .notifier_call = trace_kprobe_module_callback,
701 .priority = 1 /* Invoked after kprobe module callback */
704 /* Convert certain expected symbols into '_' when generating event names */
705 static inline void sanitize_event_name(char *name)
707 while (*name++ != '\0')
708 if (*name == ':' || *name == '.')
712 static int trace_kprobe_create(int argc, const char *argv[])
717 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
719 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
721 * $retval : fetch return value
722 * $stack : fetch stack address
723 * $stackN : fetch Nth of stack (N:0-)
724 * $comm : fetch current task comm
725 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
726 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
727 * %REG : fetch register REG
728 * Dereferencing memory fetch:
729 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
730 * Alias name of args:
731 * NAME=FETCHARG : set NAME as alias of FETCHARG.
733 * FETCHARG:TYPE : use TYPE instead of unsigned long.
735 struct trace_kprobe *tk = NULL;
737 bool is_return = false;
738 char *symbol = NULL, *tmp = NULL;
739 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
743 char buf[MAX_EVENT_NAME_LEN];
744 unsigned int flags = TPARG_FL_KERNEL;
746 switch (argv[0][0]) {
749 flags |= TPARG_FL_RETURN;
759 trace_probe_log_init("trace_kprobe", argc, argv);
761 event = strchr(&argv[0][1], ':');
765 if (isdigit(argv[0][1])) {
767 trace_probe_log_err(1, MAXACT_NO_KPROBE);
771 len = event - &argv[0][1] - 1;
773 len = strlen(&argv[0][1]);
774 if (len > MAX_EVENT_NAME_LEN - 1) {
775 trace_probe_log_err(1, BAD_MAXACT);
778 memcpy(buf, &argv[0][1], len);
780 ret = kstrtouint(buf, 0, &maxactive);
781 if (ret || !maxactive) {
782 trace_probe_log_err(1, BAD_MAXACT);
785 /* kretprobes instances are iterated over via a list. The
786 * maximum should stay reasonable.
788 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
789 trace_probe_log_err(1, MAXACT_TOO_BIG);
794 /* try to parse an address. if that fails, try to read the
795 * input as a symbol. */
796 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
797 trace_probe_log_set_index(1);
798 /* Check whether uprobe event specified */
799 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
803 /* a symbol specified */
804 symbol = kstrdup(argv[1], GFP_KERNEL);
807 /* TODO: support .init module functions */
808 ret = traceprobe_split_symbol_offset(symbol, &offset);
809 if (ret || offset < 0 || offset > UINT_MAX) {
810 trace_probe_log_err(0, BAD_PROBE_ADDR);
813 if (kprobe_on_func_entry(NULL, symbol, offset))
814 flags |= TPARG_FL_FENTRY;
815 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
816 trace_probe_log_err(0, BAD_RETPROBE);
821 trace_probe_log_set_index(0);
823 ret = traceprobe_parse_event_name(&event, &group, buf,
828 /* Make a new event name */
830 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
831 is_return ? 'r' : 'p', symbol, offset);
833 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
834 is_return ? 'r' : 'p', addr);
835 sanitize_event_name(buf);
840 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
841 argc - 2, is_return);
844 /* This must return -ENOMEM, else there is a bug */
845 WARN_ON_ONCE(ret != -ENOMEM);
846 goto out; /* We know tk is not allocated */
848 argc -= 2; argv += 2;
850 /* parse arguments */
851 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
852 tmp = kstrdup(argv[i], GFP_KERNEL);
858 trace_probe_log_set_index(i + 2);
859 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
862 goto error; /* This can be -ENOMEM */
865 ret = traceprobe_set_print_fmt(&tk->tp, is_return);
869 ret = register_trace_kprobe(tk);
871 trace_probe_log_set_index(1);
873 trace_probe_log_err(0, BAD_INSN_BNDRY);
874 else if (ret == -ENOENT)
875 trace_probe_log_err(0, BAD_PROBE_ADDR);
876 else if (ret != -ENOMEM && ret != -EEXIST)
877 trace_probe_log_err(0, FAIL_REG_PROBE);
882 trace_probe_log_clear();
889 free_trace_kprobe(tk);
893 static int create_or_delete_trace_kprobe(int argc, char **argv)
897 if (argv[0][0] == '-')
898 return dyn_event_release(argc, argv, &trace_kprobe_ops);
900 ret = trace_kprobe_create(argc, (const char **)argv);
901 return ret == -ECANCELED ? -EINVAL : ret;
904 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
906 return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
910 * kprobe_event_cmd_init - Initialize a kprobe event command object
911 * @cmd: A pointer to the dynevent_cmd struct representing the new event
912 * @buf: A pointer to the buffer used to build the command
913 * @maxlen: The length of the buffer passed in @buf
915 * Initialize a synthetic event command object. Use this before
916 * calling any of the other kprobe_event functions.
918 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
920 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
921 trace_kprobe_run_command);
923 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
926 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
927 * @cmd: A pointer to the dynevent_cmd struct representing the new event
928 * @name: The name of the kprobe event
929 * @loc: The location of the kprobe event
930 * @kretprobe: Is this a return probe?
931 * @args: Variable number of arg (pairs), one pair for each field
933 * NOTE: Users normally won't want to call this function directly, but
934 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
935 * adds a NULL to the end of the arg list. If this function is used
936 * directly, make sure the last arg in the variable arg list is NULL.
938 * Generate a kprobe event command to be executed by
939 * kprobe_event_gen_cmd_end(). This function can be used to generate the
940 * complete command or only the first part of it; in the latter case,
941 * kprobe_event_add_fields() can be used to add more fields following this.
943 * Return: 0 if successful, error otherwise.
945 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
946 const char *name, const char *loc, ...)
948 char buf[MAX_EVENT_NAME_LEN];
949 struct dynevent_arg arg;
953 if (cmd->type != DYNEVENT_TYPE_KPROBE)
957 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
959 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
961 ret = dynevent_str_add(cmd, buf);
965 dynevent_arg_init(&arg, 0);
967 ret = dynevent_arg_add(cmd, &arg, NULL);
975 field = va_arg(args, const char *);
979 if (++cmd->n_fields > MAX_TRACE_ARGS) {
985 ret = dynevent_arg_add(cmd, &arg, NULL);
993 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
996 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
997 * @cmd: A pointer to the dynevent_cmd struct representing the new event
998 * @args: Variable number of arg (pairs), one pair for each field
1000 * NOTE: Users normally won't want to call this function directly, but
1001 * rather use the kprobe_event_add_fields() wrapper, which
1002 * automatically adds a NULL to the end of the arg list. If this
1003 * function is used directly, make sure the last arg in the variable
1006 * Add probe fields to an existing kprobe command using a variable
1007 * list of args. Fields are added in the same order they're listed.
1009 * Return: 0 if successful, error otherwise.
1011 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1013 struct dynevent_arg arg;
1017 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1020 dynevent_arg_init(&arg, 0);
1022 va_start(args, cmd);
1026 field = va_arg(args, const char *);
1030 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1036 ret = dynevent_arg_add(cmd, &arg, NULL);
1044 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1047 * kprobe_event_delete - Delete a kprobe event
1048 * @name: The name of the kprobe event to delete
1050 * Delete a kprobe event with the give @name from kernel code rather
1051 * than directly from the command line.
1053 * Return: 0 if successful, error otherwise.
1055 int kprobe_event_delete(const char *name)
1057 char buf[MAX_EVENT_NAME_LEN];
1059 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1061 return trace_run_command(buf, create_or_delete_trace_kprobe);
1063 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1065 static int trace_kprobe_release(struct dyn_event *ev)
1067 struct trace_kprobe *tk = to_trace_kprobe(ev);
1068 int ret = unregister_trace_kprobe(tk);
1071 free_trace_kprobe(tk);
1075 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1077 struct trace_kprobe *tk = to_trace_kprobe(ev);
1080 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1081 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1082 trace_probe_name(&tk->tp));
1085 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1086 else if (tk->rp.kp.offset)
1087 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1090 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1092 for (i = 0; i < tk->tp.nr_args; i++)
1093 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1099 static int probes_seq_show(struct seq_file *m, void *v)
1101 struct dyn_event *ev = v;
1103 if (!is_trace_kprobe(ev))
1106 return trace_kprobe_show(m, ev);
1109 static const struct seq_operations probes_seq_op = {
1110 .start = dyn_event_seq_start,
1111 .next = dyn_event_seq_next,
1112 .stop = dyn_event_seq_stop,
1113 .show = probes_seq_show
1116 static int probes_open(struct inode *inode, struct file *file)
1120 ret = security_locked_down(LOCKDOWN_TRACEFS);
1124 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1125 ret = dyn_events_release_all(&trace_kprobe_ops);
1130 return seq_open(file, &probes_seq_op);
1133 static ssize_t probes_write(struct file *file, const char __user *buffer,
1134 size_t count, loff_t *ppos)
1136 return trace_parse_run_command(file, buffer, count, ppos,
1137 create_or_delete_trace_kprobe);
1140 static const struct file_operations kprobe_events_ops = {
1141 .owner = THIS_MODULE,
1142 .open = probes_open,
1144 .llseek = seq_lseek,
1145 .release = seq_release,
1146 .write = probes_write,
1149 /* Probes profiling interfaces */
1150 static int probes_profile_seq_show(struct seq_file *m, void *v)
1152 struct dyn_event *ev = v;
1153 struct trace_kprobe *tk;
1155 if (!is_trace_kprobe(ev))
1158 tk = to_trace_kprobe(ev);
1159 seq_printf(m, " %-44s %15lu %15lu\n",
1160 trace_probe_name(&tk->tp),
1161 trace_kprobe_nhit(tk),
1167 static const struct seq_operations profile_seq_op = {
1168 .start = dyn_event_seq_start,
1169 .next = dyn_event_seq_next,
1170 .stop = dyn_event_seq_stop,
1171 .show = probes_profile_seq_show
1174 static int profile_open(struct inode *inode, struct file *file)
1178 ret = security_locked_down(LOCKDOWN_TRACEFS);
1182 return seq_open(file, &profile_seq_op);
1185 static const struct file_operations kprobe_profile_ops = {
1186 .owner = THIS_MODULE,
1187 .open = profile_open,
1189 .llseek = seq_lseek,
1190 .release = seq_release,
1193 /* Kprobe specific fetch functions */
1195 /* Return the length of string -- including null terminal byte */
1196 static nokprobe_inline int
1197 fetch_store_strlen(unsigned long addr)
1203 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1205 } while (c && ret == 0 && len < MAX_STRING_SIZE);
1207 return (ret < 0) ? ret : len;
1210 /* Return the length of string -- including null terminal byte */
1211 static nokprobe_inline int
1212 fetch_store_strlen_user(unsigned long addr)
1214 const void __user *uaddr = (__force const void __user *)addr;
1216 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1220 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1221 * length and relative data location.
1223 static nokprobe_inline int
1224 fetch_store_string(unsigned long addr, void *dest, void *base)
1226 int maxlen = get_loc_len(*(u32 *)dest);
1230 if (unlikely(!maxlen))
1233 __dest = get_loc_data(dest, base);
1236 * Try to get string again, since the string can be changed while
1239 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1241 *(u32 *)dest = make_data_loc(ret, __dest - base);
1247 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1248 * with max length and relative data location.
1250 static nokprobe_inline int
1251 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1253 const void __user *uaddr = (__force const void __user *)addr;
1254 int maxlen = get_loc_len(*(u32 *)dest);
1258 if (unlikely(!maxlen))
1261 __dest = get_loc_data(dest, base);
1263 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1265 *(u32 *)dest = make_data_loc(ret, __dest - base);
1270 static nokprobe_inline int
1271 probe_mem_read(void *dest, void *src, size_t size)
1273 return probe_kernel_read(dest, src, size);
1276 static nokprobe_inline int
1277 probe_mem_read_user(void *dest, void *src, size_t size)
1279 const void __user *uaddr = (__force const void __user *)src;
1281 return probe_user_read(dest, uaddr, size);
1284 /* Note that we don't verify it, since the code does not come from user space */
1286 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1292 /* 1st stage: get value from context */
1295 val = regs_get_register(regs, code->param);
1297 case FETCH_OP_STACK:
1298 val = regs_get_kernel_stack_nth(regs, code->param);
1300 case FETCH_OP_STACKP:
1301 val = kernel_stack_pointer(regs);
1303 case FETCH_OP_RETVAL:
1304 val = regs_return_value(regs);
1307 val = code->immediate;
1310 val = (unsigned long)current->comm;
1313 val = (unsigned long)code->data;
1315 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1317 val = regs_get_kernel_argument(regs, code->param);
1320 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1328 return process_fetch_insn_bottom(code, val, dest, base);
1330 NOKPROBE_SYMBOL(process_fetch_insn)
1332 /* Kprobe handler */
1333 static nokprobe_inline void
1334 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1335 struct trace_event_file *trace_file)
1337 struct kprobe_trace_entry_head *entry;
1338 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1339 struct trace_event_buffer fbuffer;
1342 WARN_ON(call != trace_file->event_call);
1344 if (trace_trigger_soft_disabled(trace_file))
1347 local_save_flags(fbuffer.flags);
1348 fbuffer.pc = preempt_count();
1349 fbuffer.trace_file = trace_file;
1351 dsize = __get_data_size(&tk->tp, regs);
1354 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1356 sizeof(*entry) + tk->tp.size + dsize,
1357 fbuffer.flags, fbuffer.pc);
1361 fbuffer.regs = regs;
1362 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1363 entry->ip = (unsigned long)tk->rp.kp.addr;
1364 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1366 trace_event_buffer_commit(&fbuffer);
1370 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1372 struct event_file_link *link;
1374 trace_probe_for_each_link_rcu(link, &tk->tp)
1375 __kprobe_trace_func(tk, regs, link->file);
1377 NOKPROBE_SYMBOL(kprobe_trace_func);
1379 /* Kretprobe handler */
1380 static nokprobe_inline void
1381 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1382 struct pt_regs *regs,
1383 struct trace_event_file *trace_file)
1385 struct kretprobe_trace_entry_head *entry;
1386 struct trace_event_buffer fbuffer;
1387 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1390 WARN_ON(call != trace_file->event_call);
1392 if (trace_trigger_soft_disabled(trace_file))
1395 local_save_flags(fbuffer.flags);
1396 fbuffer.pc = preempt_count();
1397 fbuffer.trace_file = trace_file;
1399 dsize = __get_data_size(&tk->tp, regs);
1401 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1403 sizeof(*entry) + tk->tp.size + dsize,
1404 fbuffer.flags, fbuffer.pc);
1408 fbuffer.regs = regs;
1409 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1410 entry->func = (unsigned long)tk->rp.kp.addr;
1411 entry->ret_ip = (unsigned long)ri->ret_addr;
1412 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1414 trace_event_buffer_commit(&fbuffer);
1418 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1419 struct pt_regs *regs)
1421 struct event_file_link *link;
1423 trace_probe_for_each_link_rcu(link, &tk->tp)
1424 __kretprobe_trace_func(tk, ri, regs, link->file);
1426 NOKPROBE_SYMBOL(kretprobe_trace_func);
1428 /* Event entry printers */
1429 static enum print_line_t
1430 print_kprobe_event(struct trace_iterator *iter, int flags,
1431 struct trace_event *event)
1433 struct kprobe_trace_entry_head *field;
1434 struct trace_seq *s = &iter->seq;
1435 struct trace_probe *tp;
1437 field = (struct kprobe_trace_entry_head *)iter->ent;
1438 tp = trace_probe_primary_from_call(
1439 container_of(event, struct trace_event_call, event));
1440 if (WARN_ON_ONCE(!tp))
1443 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1445 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1448 trace_seq_putc(s, ')');
1450 if (print_probe_args(s, tp->args, tp->nr_args,
1451 (u8 *)&field[1], field) < 0)
1454 trace_seq_putc(s, '\n');
1456 return trace_handle_return(s);
1459 static enum print_line_t
1460 print_kretprobe_event(struct trace_iterator *iter, int flags,
1461 struct trace_event *event)
1463 struct kretprobe_trace_entry_head *field;
1464 struct trace_seq *s = &iter->seq;
1465 struct trace_probe *tp;
1467 field = (struct kretprobe_trace_entry_head *)iter->ent;
1468 tp = trace_probe_primary_from_call(
1469 container_of(event, struct trace_event_call, event));
1470 if (WARN_ON_ONCE(!tp))
1473 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1475 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1478 trace_seq_puts(s, " <- ");
1480 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1483 trace_seq_putc(s, ')');
1485 if (print_probe_args(s, tp->args, tp->nr_args,
1486 (u8 *)&field[1], field) < 0)
1489 trace_seq_putc(s, '\n');
1492 return trace_handle_return(s);
1496 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1499 struct kprobe_trace_entry_head field;
1500 struct trace_probe *tp;
1502 tp = trace_probe_primary_from_call(event_call);
1503 if (WARN_ON_ONCE(!tp))
1506 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1508 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1511 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1514 struct kretprobe_trace_entry_head field;
1515 struct trace_probe *tp;
1517 tp = trace_probe_primary_from_call(event_call);
1518 if (WARN_ON_ONCE(!tp))
1521 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1522 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1524 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1527 #ifdef CONFIG_PERF_EVENTS
1529 /* Kprobe profile handler */
1531 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1533 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1534 struct kprobe_trace_entry_head *entry;
1535 struct hlist_head *head;
1536 int size, __size, dsize;
1539 if (bpf_prog_array_valid(call)) {
1540 unsigned long orig_ip = instruction_pointer(regs);
1543 ret = trace_call_bpf(call, regs);
1546 * We need to check and see if we modified the pc of the
1547 * pt_regs, and if so return 1 so that we don't do the
1550 if (orig_ip != instruction_pointer(regs))
1556 head = this_cpu_ptr(call->perf_events);
1557 if (hlist_empty(head))
1560 dsize = __get_data_size(&tk->tp, regs);
1561 __size = sizeof(*entry) + tk->tp.size + dsize;
1562 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1563 size -= sizeof(u32);
1565 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1569 entry->ip = (unsigned long)tk->rp.kp.addr;
1570 memset(&entry[1], 0, dsize);
1571 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1572 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1576 NOKPROBE_SYMBOL(kprobe_perf_func);
1578 /* Kretprobe profile handler */
1580 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1581 struct pt_regs *regs)
1583 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1584 struct kretprobe_trace_entry_head *entry;
1585 struct hlist_head *head;
1586 int size, __size, dsize;
1589 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1592 head = this_cpu_ptr(call->perf_events);
1593 if (hlist_empty(head))
1596 dsize = __get_data_size(&tk->tp, regs);
1597 __size = sizeof(*entry) + tk->tp.size + dsize;
1598 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1599 size -= sizeof(u32);
1601 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1605 entry->func = (unsigned long)tk->rp.kp.addr;
1606 entry->ret_ip = (unsigned long)ri->ret_addr;
1607 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1608 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1611 NOKPROBE_SYMBOL(kretprobe_perf_func);
1613 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1614 const char **symbol, u64 *probe_offset,
1615 u64 *probe_addr, bool perf_type_tracepoint)
1617 const char *pevent = trace_event_name(event->tp_event);
1618 const char *group = event->tp_event->class->system;
1619 struct trace_kprobe *tk;
1621 if (perf_type_tracepoint)
1622 tk = find_trace_kprobe(pevent, group);
1624 tk = event->tp_event->data;
1628 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1629 : BPF_FD_TYPE_KPROBE;
1631 *symbol = tk->symbol;
1632 *probe_offset = tk->rp.kp.offset;
1637 *probe_addr = (unsigned long)tk->rp.kp.addr;
1641 #endif /* CONFIG_PERF_EVENTS */
1644 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1646 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1647 * lockless, but we can't race with this __init function.
1649 static int kprobe_register(struct trace_event_call *event,
1650 enum trace_reg type, void *data)
1652 struct trace_event_file *file = data;
1655 case TRACE_REG_REGISTER:
1656 return enable_trace_kprobe(event, file);
1657 case TRACE_REG_UNREGISTER:
1658 return disable_trace_kprobe(event, file);
1660 #ifdef CONFIG_PERF_EVENTS
1661 case TRACE_REG_PERF_REGISTER:
1662 return enable_trace_kprobe(event, NULL);
1663 case TRACE_REG_PERF_UNREGISTER:
1664 return disable_trace_kprobe(event, NULL);
1665 case TRACE_REG_PERF_OPEN:
1666 case TRACE_REG_PERF_CLOSE:
1667 case TRACE_REG_PERF_ADD:
1668 case TRACE_REG_PERF_DEL:
1675 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1677 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1680 raw_cpu_inc(*tk->nhit);
1682 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1683 kprobe_trace_func(tk, regs);
1684 #ifdef CONFIG_PERF_EVENTS
1685 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1686 ret = kprobe_perf_func(tk, regs);
1690 NOKPROBE_SYMBOL(kprobe_dispatcher);
1693 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1695 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1697 raw_cpu_inc(*tk->nhit);
1699 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1700 kretprobe_trace_func(tk, ri, regs);
1701 #ifdef CONFIG_PERF_EVENTS
1702 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1703 kretprobe_perf_func(tk, ri, regs);
1705 return 0; /* We don't tweek kernel, so just return 0 */
1707 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1709 static struct trace_event_functions kretprobe_funcs = {
1710 .trace = print_kretprobe_event
1713 static struct trace_event_functions kprobe_funcs = {
1714 .trace = print_kprobe_event
1717 static struct trace_event_fields kretprobe_fields_array[] = {
1718 { .type = TRACE_FUNCTION_TYPE,
1719 .define_fields = kretprobe_event_define_fields },
1723 static struct trace_event_fields kprobe_fields_array[] = {
1724 { .type = TRACE_FUNCTION_TYPE,
1725 .define_fields = kprobe_event_define_fields },
1729 static inline void init_trace_event_call(struct trace_kprobe *tk)
1731 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1733 if (trace_kprobe_is_return(tk)) {
1734 call->event.funcs = &kretprobe_funcs;
1735 call->class->fields_array = kretprobe_fields_array;
1737 call->event.funcs = &kprobe_funcs;
1738 call->class->fields_array = kprobe_fields_array;
1741 call->flags = TRACE_EVENT_FL_KPROBE;
1742 call->class->reg = kprobe_register;
1745 static int register_kprobe_event(struct trace_kprobe *tk)
1747 init_trace_event_call(tk);
1749 return trace_probe_register_event_call(&tk->tp);
1752 static int unregister_kprobe_event(struct trace_kprobe *tk)
1754 return trace_probe_unregister_event_call(&tk->tp);
1757 #ifdef CONFIG_PERF_EVENTS
1758 /* create a trace_kprobe, but don't add it to global lists */
1759 struct trace_event_call *
1760 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1763 struct trace_kprobe *tk;
1768 * local trace_kprobes are not added to dyn_event, so they are never
1769 * searched in find_trace_kprobe(). Therefore, there is no concern of
1770 * duplicated name here.
1772 event = func ? func : "DUMMY_EVENT";
1774 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1775 offs, 0 /* maxactive */, 0 /* nargs */,
1779 pr_info("Failed to allocate trace_probe.(%d)\n",
1781 return ERR_CAST(tk);
1784 init_trace_event_call(tk);
1786 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1791 ret = __register_trace_kprobe(tk);
1795 return trace_probe_event_call(&tk->tp);
1797 free_trace_kprobe(tk);
1798 return ERR_PTR(ret);
1801 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1803 struct trace_kprobe *tk;
1805 tk = trace_kprobe_primary_from_call(event_call);
1809 if (trace_probe_is_enabled(&tk->tp)) {
1814 __unregister_trace_kprobe(tk);
1816 free_trace_kprobe(tk);
1818 #endif /* CONFIG_PERF_EVENTS */
1820 static __init void enable_boot_kprobe_events(void)
1822 struct trace_array *tr = top_trace_array();
1823 struct trace_event_file *file;
1824 struct trace_kprobe *tk;
1825 struct dyn_event *pos;
1827 mutex_lock(&event_mutex);
1828 for_each_trace_kprobe(tk, pos) {
1829 list_for_each_entry(file, &tr->events, list)
1830 if (file->event_call == trace_probe_event_call(&tk->tp))
1831 trace_event_enable_disable(file, 1, 0);
1833 mutex_unlock(&event_mutex);
1836 static __init void setup_boot_kprobe_events(void)
1838 char *p, *cmd = kprobe_boot_events_buf;
1841 strreplace(kprobe_boot_events_buf, ',', ' ');
1843 while (cmd && *cmd != '\0') {
1844 p = strchr(cmd, ';');
1848 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1850 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1852 kprobe_boot_events_enabled = true;
1857 enable_boot_kprobe_events();
1861 * Register dynevent at subsys_initcall. This allows kernel to setup kprobe
1862 * events in fs_initcall without tracefs.
1864 static __init int init_kprobe_trace_early(void)
1868 ret = dyn_event_register(&trace_kprobe_ops);
1872 if (register_module_notifier(&trace_kprobe_module_nb))
1877 subsys_initcall(init_kprobe_trace_early);
1879 /* Make a tracefs interface for controlling probe points */
1880 static __init int init_kprobe_trace(void)
1882 struct dentry *d_tracer;
1883 struct dentry *entry;
1885 d_tracer = tracing_init_dentry();
1886 if (IS_ERR(d_tracer))
1889 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1890 NULL, &kprobe_events_ops);
1892 /* Event list interface */
1894 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1896 /* Profile interface */
1897 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1898 NULL, &kprobe_profile_ops);
1901 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1903 setup_boot_kprobe_events();
1907 fs_initcall(init_kprobe_trace);
1910 #ifdef CONFIG_FTRACE_STARTUP_TEST
1911 static __init struct trace_event_file *
1912 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1914 struct trace_event_file *file;
1916 list_for_each_entry(file, &tr->events, list)
1917 if (file->event_call == trace_probe_event_call(&tk->tp))
1924 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1925 * stage, we can do this lockless.
1927 static __init int kprobe_trace_self_tests_init(void)
1930 int (*target)(int, int, int, int, int, int);
1931 struct trace_kprobe *tk;
1932 struct trace_event_file *file;
1934 if (tracing_is_disabled())
1937 if (kprobe_boot_events_enabled) {
1938 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1942 target = kprobe_trace_selftest_target;
1944 pr_info("Testing kprobe tracing: ");
1946 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1947 create_or_delete_trace_kprobe);
1948 if (WARN_ON_ONCE(ret)) {
1949 pr_warn("error on probing function entry.\n");
1952 /* Enable trace point */
1953 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1954 if (WARN_ON_ONCE(tk == NULL)) {
1955 pr_warn("error on getting new probe.\n");
1958 file = find_trace_probe_file(tk, top_trace_array());
1959 if (WARN_ON_ONCE(file == NULL)) {
1960 pr_warn("error on getting probe file.\n");
1963 enable_trace_kprobe(
1964 trace_probe_event_call(&tk->tp), file);
1968 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1969 create_or_delete_trace_kprobe);
1970 if (WARN_ON_ONCE(ret)) {
1971 pr_warn("error on probing function return.\n");
1974 /* Enable trace point */
1975 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1976 if (WARN_ON_ONCE(tk == NULL)) {
1977 pr_warn("error on getting 2nd new probe.\n");
1980 file = find_trace_probe_file(tk, top_trace_array());
1981 if (WARN_ON_ONCE(file == NULL)) {
1982 pr_warn("error on getting probe file.\n");
1985 enable_trace_kprobe(
1986 trace_probe_event_call(&tk->tp), file);
1993 ret = target(1, 2, 3, 4, 5, 6);
1996 * Not expecting an error here, the check is only to prevent the
1997 * optimizer from removing the call to target() as otherwise there
1998 * are no side-effects and the call is never performed.
2003 /* Disable trace points before removing it */
2004 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2005 if (WARN_ON_ONCE(tk == NULL)) {
2006 pr_warn("error on getting test probe.\n");
2009 if (trace_kprobe_nhit(tk) != 1) {
2010 pr_warn("incorrect number of testprobe hits\n");
2014 file = find_trace_probe_file(tk, top_trace_array());
2015 if (WARN_ON_ONCE(file == NULL)) {
2016 pr_warn("error on getting probe file.\n");
2019 disable_trace_kprobe(
2020 trace_probe_event_call(&tk->tp), file);
2023 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2024 if (WARN_ON_ONCE(tk == NULL)) {
2025 pr_warn("error on getting 2nd test probe.\n");
2028 if (trace_kprobe_nhit(tk) != 1) {
2029 pr_warn("incorrect number of testprobe2 hits\n");
2033 file = find_trace_probe_file(tk, top_trace_array());
2034 if (WARN_ON_ONCE(file == NULL)) {
2035 pr_warn("error on getting probe file.\n");
2038 disable_trace_kprobe(
2039 trace_probe_event_call(&tk->tp), file);
2042 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
2043 if (WARN_ON_ONCE(ret)) {
2044 pr_warn("error on deleting a probe.\n");
2048 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
2049 if (WARN_ON_ONCE(ret)) {
2050 pr_warn("error on deleting a probe.\n");
2055 ret = dyn_events_release_all(&trace_kprobe_ops);
2056 if (WARN_ON_ONCE(ret)) {
2057 pr_warn("error on cleaning up probes.\n");
2061 * Wait for the optimizer work to finish. Otherwise it might fiddle
2062 * with probes in already freed __init text.
2064 wait_for_kprobe_optimizer();
2066 pr_cont("NG: Some tests are failed. Please check them.\n");
2072 late_initcall(kprobe_trace_self_tests_init);