2 * Kprobes-based tracing events
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/module.h>
21 #include <linux/uaccess.h>
23 #include "trace_probe.h"
25 #define KPROBE_EVENT_SYSTEM "kprobes"
28 * Kprobe event core functions
31 struct list_head list
;
32 struct kretprobe rp
; /* Use rp.kp for kprobe use */
33 unsigned long __percpu
*nhit
;
34 const char *symbol
; /* symbol name */
35 struct trace_probe tp
;
38 #define SIZEOF_TRACE_KPROBE(n) \
39 (offsetof(struct trace_kprobe, tp.args) + \
40 (sizeof(struct probe_arg) * (n)))
43 static nokprobe_inline
bool trace_kprobe_is_return(struct trace_kprobe
*tk
)
45 return tk
->rp
.handler
!= NULL
;
48 static nokprobe_inline
const char *trace_kprobe_symbol(struct trace_kprobe
*tk
)
50 return tk
->symbol
? tk
->symbol
: "unknown";
53 static nokprobe_inline
unsigned long trace_kprobe_offset(struct trace_kprobe
*tk
)
55 return tk
->rp
.kp
.offset
;
58 static nokprobe_inline
bool trace_kprobe_has_gone(struct trace_kprobe
*tk
)
60 return !!(kprobe_gone(&tk
->rp
.kp
));
63 static nokprobe_inline
bool trace_kprobe_within_module(struct trace_kprobe
*tk
,
66 int len
= strlen(mod
->name
);
67 const char *name
= trace_kprobe_symbol(tk
);
68 return strncmp(mod
->name
, name
, len
) == 0 && name
[len
] == ':';
71 static nokprobe_inline
bool trace_kprobe_is_on_module(struct trace_kprobe
*tk
)
73 return !!strchr(trace_kprobe_symbol(tk
), ':');
76 static int register_kprobe_event(struct trace_kprobe
*tk
);
77 static int unregister_kprobe_event(struct trace_kprobe
*tk
);
79 static DEFINE_MUTEX(probe_lock
);
80 static LIST_HEAD(probe_list
);
82 static int kprobe_dispatcher(struct kprobe
*kp
, struct pt_regs
*regs
);
83 static int kretprobe_dispatcher(struct kretprobe_instance
*ri
,
84 struct pt_regs
*regs
);
86 /* Memory fetching by symbol */
93 unsigned long update_symbol_cache(struct symbol_cache
*sc
)
95 sc
->addr
= (unsigned long)kallsyms_lookup_name(sc
->symbol
);
98 sc
->addr
+= sc
->offset
;
103 void free_symbol_cache(struct symbol_cache
*sc
)
109 struct symbol_cache
*alloc_symbol_cache(const char *sym
, long offset
)
111 struct symbol_cache
*sc
;
113 if (!sym
|| strlen(sym
) == 0)
116 sc
= kzalloc(sizeof(struct symbol_cache
), GFP_KERNEL
);
120 sc
->symbol
= kstrdup(sym
, GFP_KERNEL
);
126 update_symbol_cache(sc
);
132 * Kprobes-specific fetch functions
134 #define DEFINE_FETCH_stack(type) \
135 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
136 void *offset, void *dest) \
138 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
139 (unsigned int)((unsigned long)offset)); \
141 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
143 DEFINE_BASIC_FETCH_FUNCS(stack
)
144 /* No string on the stack entry */
145 #define fetch_stack_string NULL
146 #define fetch_stack_string_size NULL
148 #define DEFINE_FETCH_memory(type) \
149 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
150 void *addr, void *dest) \
153 if (probe_kernel_address(addr, retval)) \
156 *(type *)dest = retval; \
158 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
160 DEFINE_BASIC_FETCH_FUNCS(memory
)
162 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
163 * length and relative data location.
165 static void FETCH_FUNC_NAME(memory
, string
)(struct pt_regs
*regs
,
166 void *addr
, void *dest
)
168 int maxlen
= get_rloc_len(*(u32
*)dest
);
169 u8
*dst
= get_rloc_data(dest
);
176 * Try to get string again, since the string can be changed while
179 ret
= strncpy_from_unsafe(dst
, addr
, maxlen
);
181 if (ret
< 0) { /* Failed to fetch string */
183 *(u32
*)dest
= make_data_rloc(0, get_rloc_offs(*(u32
*)dest
));
185 *(u32
*)dest
= make_data_rloc(ret
, get_rloc_offs(*(u32
*)dest
));
188 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory
, string
));
190 /* Return the length of string -- including null terminal byte */
191 static void FETCH_FUNC_NAME(memory
, string_size
)(struct pt_regs
*regs
,
192 void *addr
, void *dest
)
203 ret
= __copy_from_user_inatomic(&c
, (u8
*)addr
+ len
, 1);
205 } while (c
&& ret
== 0 && len
< MAX_STRING_SIZE
);
210 if (ret
< 0) /* Failed to check the length */
215 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory
, string_size
));
217 #define DEFINE_FETCH_symbol(type) \
218 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
220 struct symbol_cache *sc = data; \
222 fetch_memory_##type(regs, (void *)sc->addr, dest); \
226 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
228 DEFINE_BASIC_FETCH_FUNCS(symbol
)
229 DEFINE_FETCH_symbol(string
)
230 DEFINE_FETCH_symbol(string_size
)
232 /* kprobes don't support file_offset fetch methods */
233 #define fetch_file_offset_u8 NULL
234 #define fetch_file_offset_u16 NULL
235 #define fetch_file_offset_u32 NULL
236 #define fetch_file_offset_u64 NULL
237 #define fetch_file_offset_string NULL
238 #define fetch_file_offset_string_size NULL
240 /* Fetch type information table */
241 static const struct fetch_type kprobes_fetch_type_table
[] = {
243 [FETCH_TYPE_STRING
] = __ASSIGN_FETCH_TYPE("string", string
, string
,
244 sizeof(u32
), 1, "__data_loc char[]"),
245 [FETCH_TYPE_STRSIZE
] = __ASSIGN_FETCH_TYPE("string_size", u32
,
246 string_size
, sizeof(u32
), 0, "u32"),
248 ASSIGN_FETCH_TYPE(u8
, u8
, 0),
249 ASSIGN_FETCH_TYPE(u16
, u16
, 0),
250 ASSIGN_FETCH_TYPE(u32
, u32
, 0),
251 ASSIGN_FETCH_TYPE(u64
, u64
, 0),
252 ASSIGN_FETCH_TYPE(s8
, u8
, 1),
253 ASSIGN_FETCH_TYPE(s16
, u16
, 1),
254 ASSIGN_FETCH_TYPE(s32
, u32
, 1),
255 ASSIGN_FETCH_TYPE(s64
, u64
, 1),
257 ASSIGN_FETCH_TYPE_END
261 * Allocate new trace_probe and initialize it (including kprobes).
263 static struct trace_kprobe
*alloc_trace_kprobe(const char *group
,
268 int nargs
, bool is_return
)
270 struct trace_kprobe
*tk
;
273 tk
= kzalloc(SIZEOF_TRACE_KPROBE(nargs
), GFP_KERNEL
);
277 tk
->nhit
= alloc_percpu(unsigned long);
282 tk
->symbol
= kstrdup(symbol
, GFP_KERNEL
);
285 tk
->rp
.kp
.symbol_name
= tk
->symbol
;
286 tk
->rp
.kp
.offset
= offs
;
288 tk
->rp
.kp
.addr
= addr
;
291 tk
->rp
.handler
= kretprobe_dispatcher
;
293 tk
->rp
.kp
.pre_handler
= kprobe_dispatcher
;
295 if (!event
|| !is_good_name(event
)) {
300 tk
->tp
.call
.class = &tk
->tp
.class;
301 tk
->tp
.call
.name
= kstrdup(event
, GFP_KERNEL
);
302 if (!tk
->tp
.call
.name
)
305 if (!group
|| !is_good_name(group
)) {
310 tk
->tp
.class.system
= kstrdup(group
, GFP_KERNEL
);
311 if (!tk
->tp
.class.system
)
314 INIT_LIST_HEAD(&tk
->list
);
315 INIT_LIST_HEAD(&tk
->tp
.files
);
318 kfree(tk
->tp
.call
.name
);
320 free_percpu(tk
->nhit
);
325 static void free_trace_kprobe(struct trace_kprobe
*tk
)
329 for (i
= 0; i
< tk
->tp
.nr_args
; i
++)
330 traceprobe_free_probe_arg(&tk
->tp
.args
[i
]);
332 kfree(tk
->tp
.call
.class->system
);
333 kfree(tk
->tp
.call
.name
);
335 free_percpu(tk
->nhit
);
339 static struct trace_kprobe
*find_trace_kprobe(const char *event
,
342 struct trace_kprobe
*tk
;
344 list_for_each_entry(tk
, &probe_list
, list
)
345 if (strcmp(trace_event_name(&tk
->tp
.call
), event
) == 0 &&
346 strcmp(tk
->tp
.call
.class->system
, group
) == 0)
353 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
356 enable_trace_kprobe(struct trace_kprobe
*tk
, struct trace_event_file
*file
)
361 struct event_file_link
*link
;
363 link
= kmalloc(sizeof(*link
), GFP_KERNEL
);
370 list_add_tail_rcu(&link
->list
, &tk
->tp
.files
);
372 tk
->tp
.flags
|= TP_FLAG_TRACE
;
374 tk
->tp
.flags
|= TP_FLAG_PROFILE
;
376 if (trace_probe_is_registered(&tk
->tp
) && !trace_kprobe_has_gone(tk
)) {
377 if (trace_kprobe_is_return(tk
))
378 ret
= enable_kretprobe(&tk
->rp
);
380 ret
= enable_kprobe(&tk
->rp
.kp
);
387 * Disable trace_probe
388 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
391 disable_trace_kprobe(struct trace_kprobe
*tk
, struct trace_event_file
*file
)
393 struct event_file_link
*link
= NULL
;
398 link
= find_event_file_link(&tk
->tp
, file
);
404 list_del_rcu(&link
->list
);
406 if (!list_empty(&tk
->tp
.files
))
409 tk
->tp
.flags
&= ~TP_FLAG_TRACE
;
411 tk
->tp
.flags
&= ~TP_FLAG_PROFILE
;
413 if (!trace_probe_is_enabled(&tk
->tp
) && trace_probe_is_registered(&tk
->tp
)) {
414 if (trace_kprobe_is_return(tk
))
415 disable_kretprobe(&tk
->rp
);
417 disable_kprobe(&tk
->rp
.kp
);
423 * Synchronize with kprobe_trace_func/kretprobe_trace_func
424 * to ensure disabled (all running handlers are finished).
425 * This is not only for kfree(), but also the caller,
426 * trace_remove_event_call() supposes it for releasing
427 * event_call related objects, which will be accessed in
428 * the kprobe_trace_func/kretprobe_trace_func.
431 kfree(link
); /* Ignored if link == NULL */
437 /* Internal register function - just handle k*probes and flags */
438 static int __register_trace_kprobe(struct trace_kprobe
*tk
)
442 if (trace_probe_is_registered(&tk
->tp
))
445 for (i
= 0; i
< tk
->tp
.nr_args
; i
++)
446 traceprobe_update_arg(&tk
->tp
.args
[i
]);
448 /* Set/clear disabled flag according to tp->flag */
449 if (trace_probe_is_enabled(&tk
->tp
))
450 tk
->rp
.kp
.flags
&= ~KPROBE_FLAG_DISABLED
;
452 tk
->rp
.kp
.flags
|= KPROBE_FLAG_DISABLED
;
454 if (trace_kprobe_is_return(tk
))
455 ret
= register_kretprobe(&tk
->rp
);
457 ret
= register_kprobe(&tk
->rp
.kp
);
460 tk
->tp
.flags
|= TP_FLAG_REGISTERED
;
462 pr_warn("Could not insert probe at %s+%lu: %d\n",
463 trace_kprobe_symbol(tk
), trace_kprobe_offset(tk
), ret
);
464 if (ret
== -ENOENT
&& trace_kprobe_is_on_module(tk
)) {
465 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
467 } else if (ret
== -EILSEQ
) {
468 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
477 /* Internal unregister function - just handle k*probes and flags */
478 static void __unregister_trace_kprobe(struct trace_kprobe
*tk
)
480 if (trace_probe_is_registered(&tk
->tp
)) {
481 if (trace_kprobe_is_return(tk
))
482 unregister_kretprobe(&tk
->rp
);
484 unregister_kprobe(&tk
->rp
.kp
);
485 tk
->tp
.flags
&= ~TP_FLAG_REGISTERED
;
486 /* Cleanup kprobe for reuse */
487 if (tk
->rp
.kp
.symbol_name
)
488 tk
->rp
.kp
.addr
= NULL
;
492 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
493 static int unregister_trace_kprobe(struct trace_kprobe
*tk
)
495 /* Enabled event can not be unregistered */
496 if (trace_probe_is_enabled(&tk
->tp
))
499 /* Will fail if probe is being used by ftrace or perf */
500 if (unregister_kprobe_event(tk
))
503 __unregister_trace_kprobe(tk
);
509 /* Register a trace_probe and probe_event */
510 static int register_trace_kprobe(struct trace_kprobe
*tk
)
512 struct trace_kprobe
*old_tk
;
515 mutex_lock(&probe_lock
);
517 /* Delete old (same name) event if exist */
518 old_tk
= find_trace_kprobe(trace_event_name(&tk
->tp
.call
),
519 tk
->tp
.call
.class->system
);
521 ret
= unregister_trace_kprobe(old_tk
);
524 free_trace_kprobe(old_tk
);
527 /* Register new event */
528 ret
= register_kprobe_event(tk
);
530 pr_warn("Failed to register probe event(%d)\n", ret
);
534 /* Register k*probe */
535 ret
= __register_trace_kprobe(tk
);
537 unregister_kprobe_event(tk
);
539 list_add_tail(&tk
->list
, &probe_list
);
542 mutex_unlock(&probe_lock
);
546 /* Module notifier call back, checking event on the module */
547 static int trace_kprobe_module_callback(struct notifier_block
*nb
,
548 unsigned long val
, void *data
)
550 struct module
*mod
= data
;
551 struct trace_kprobe
*tk
;
554 if (val
!= MODULE_STATE_COMING
)
557 /* Update probes on coming module */
558 mutex_lock(&probe_lock
);
559 list_for_each_entry(tk
, &probe_list
, list
) {
560 if (trace_kprobe_within_module(tk
, mod
)) {
561 /* Don't need to check busy - this should have gone. */
562 __unregister_trace_kprobe(tk
);
563 ret
= __register_trace_kprobe(tk
);
565 pr_warn("Failed to re-register probe %s on %s: %d\n",
566 trace_event_name(&tk
->tp
.call
),
570 mutex_unlock(&probe_lock
);
575 static struct notifier_block trace_kprobe_module_nb
= {
576 .notifier_call
= trace_kprobe_module_callback
,
577 .priority
= 1 /* Invoked after kprobe module callback */
580 static int create_trace_kprobe(int argc
, char **argv
)
584 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
585 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
587 * $retval : fetch return value
588 * $stack : fetch stack address
589 * $stackN : fetch Nth of stack (N:0-)
590 * $comm : fetch current task comm
591 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
592 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
593 * %REG : fetch register REG
594 * Dereferencing memory fetch:
595 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
596 * Alias name of args:
597 * NAME=FETCHARG : set NAME as alias of FETCHARG.
599 * FETCHARG:TYPE : use TYPE instead of unsigned long.
601 struct trace_kprobe
*tk
;
603 bool is_return
= false, is_delete
= false;
604 char *symbol
= NULL
, *event
= NULL
, *group
= NULL
;
606 unsigned long offset
= 0;
608 char buf
[MAX_EVENT_NAME_LEN
];
610 /* argc must be >= 1 */
611 if (argv
[0][0] == 'p')
613 else if (argv
[0][0] == 'r')
615 else if (argv
[0][0] == '-')
618 pr_info("Probe definition must be started with 'p', 'r' or"
623 if (argv
[0][1] == ':') {
625 if (strchr(event
, '/')) {
627 event
= strchr(group
, '/') + 1;
629 if (strlen(group
) == 0) {
630 pr_info("Group name is not specified\n");
634 if (strlen(event
) == 0) {
635 pr_info("Event name is not specified\n");
640 group
= KPROBE_EVENT_SYSTEM
;
644 pr_info("Delete command needs an event name.\n");
647 mutex_lock(&probe_lock
);
648 tk
= find_trace_kprobe(event
, group
);
650 mutex_unlock(&probe_lock
);
651 pr_info("Event %s/%s doesn't exist.\n", group
, event
);
654 /* delete an event */
655 ret
= unregister_trace_kprobe(tk
);
657 free_trace_kprobe(tk
);
658 mutex_unlock(&probe_lock
);
663 pr_info("Probe point is not specified.\n");
666 if (isdigit(argv
[1][0])) {
668 pr_info("Return probe point must be a symbol.\n");
671 /* an address specified */
672 ret
= kstrtoul(&argv
[1][0], 0, (unsigned long *)&addr
);
674 pr_info("Failed to parse address.\n");
678 /* a symbol specified */
680 /* TODO: support .init module functions */
681 ret
= traceprobe_split_symbol_offset(symbol
, &offset
);
683 pr_info("Failed to parse symbol.\n");
686 if (offset
&& is_return
) {
687 pr_info("Return probe must be used without offset.\n");
691 argc
-= 2; argv
+= 2;
695 /* Make a new event name */
697 snprintf(buf
, MAX_EVENT_NAME_LEN
, "%c_%s_%ld",
698 is_return
? 'r' : 'p', symbol
, offset
);
700 snprintf(buf
, MAX_EVENT_NAME_LEN
, "%c_0x%p",
701 is_return
? 'r' : 'p', addr
);
704 tk
= alloc_trace_kprobe(group
, event
, addr
, symbol
, offset
, argc
,
707 pr_info("Failed to allocate trace_probe.(%d)\n",
712 /* parse arguments */
714 for (i
= 0; i
< argc
&& i
< MAX_TRACE_ARGS
; i
++) {
715 struct probe_arg
*parg
= &tk
->tp
.args
[i
];
717 /* Increment count for freeing args in error case */
720 /* Parse argument name */
721 arg
= strchr(argv
[i
], '=');
724 parg
->name
= kstrdup(argv
[i
], GFP_KERNEL
);
727 /* If argument name is omitted, set "argN" */
728 snprintf(buf
, MAX_EVENT_NAME_LEN
, "arg%d", i
+ 1);
729 parg
->name
= kstrdup(buf
, GFP_KERNEL
);
733 pr_info("Failed to allocate argument[%d] name.\n", i
);
738 if (!is_good_name(parg
->name
)) {
739 pr_info("Invalid argument[%d] name: %s\n",
745 if (traceprobe_conflict_field_name(parg
->name
,
747 pr_info("Argument[%d] name '%s' conflicts with "
748 "another field.\n", i
, argv
[i
]);
753 /* Parse fetch argument */
754 ret
= traceprobe_parse_probe_arg(arg
, &tk
->tp
.size
, parg
,
756 kprobes_fetch_type_table
);
758 pr_info("Parse error at argument[%d]. (%d)\n", i
, ret
);
763 ret
= register_trace_kprobe(tk
);
769 free_trace_kprobe(tk
);
773 static int release_all_trace_kprobes(void)
775 struct trace_kprobe
*tk
;
778 mutex_lock(&probe_lock
);
779 /* Ensure no probe is in use. */
780 list_for_each_entry(tk
, &probe_list
, list
)
781 if (trace_probe_is_enabled(&tk
->tp
)) {
785 /* TODO: Use batch unregistration */
786 while (!list_empty(&probe_list
)) {
787 tk
= list_entry(probe_list
.next
, struct trace_kprobe
, list
);
788 ret
= unregister_trace_kprobe(tk
);
791 free_trace_kprobe(tk
);
795 mutex_unlock(&probe_lock
);
800 /* Probes listing interfaces */
801 static void *probes_seq_start(struct seq_file
*m
, loff_t
*pos
)
803 mutex_lock(&probe_lock
);
804 return seq_list_start(&probe_list
, *pos
);
807 static void *probes_seq_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
809 return seq_list_next(v
, &probe_list
, pos
);
812 static void probes_seq_stop(struct seq_file
*m
, void *v
)
814 mutex_unlock(&probe_lock
);
817 static int probes_seq_show(struct seq_file
*m
, void *v
)
819 struct trace_kprobe
*tk
= v
;
822 seq_putc(m
, trace_kprobe_is_return(tk
) ? 'r' : 'p');
823 seq_printf(m
, ":%s/%s", tk
->tp
.call
.class->system
,
824 trace_event_name(&tk
->tp
.call
));
827 seq_printf(m
, " 0x%p", tk
->rp
.kp
.addr
);
828 else if (tk
->rp
.kp
.offset
)
829 seq_printf(m
, " %s+%u", trace_kprobe_symbol(tk
),
832 seq_printf(m
, " %s", trace_kprobe_symbol(tk
));
834 for (i
= 0; i
< tk
->tp
.nr_args
; i
++)
835 seq_printf(m
, " %s=%s", tk
->tp
.args
[i
].name
, tk
->tp
.args
[i
].comm
);
841 static const struct seq_operations probes_seq_op
= {
842 .start
= probes_seq_start
,
843 .next
= probes_seq_next
,
844 .stop
= probes_seq_stop
,
845 .show
= probes_seq_show
848 static int probes_open(struct inode
*inode
, struct file
*file
)
852 if ((file
->f_mode
& FMODE_WRITE
) && (file
->f_flags
& O_TRUNC
)) {
853 ret
= release_all_trace_kprobes();
858 return seq_open(file
, &probes_seq_op
);
861 static ssize_t
probes_write(struct file
*file
, const char __user
*buffer
,
862 size_t count
, loff_t
*ppos
)
864 return traceprobe_probes_write(file
, buffer
, count
, ppos
,
865 create_trace_kprobe
);
868 static const struct file_operations kprobe_events_ops
= {
869 .owner
= THIS_MODULE
,
873 .release
= seq_release
,
874 .write
= probes_write
,
877 /* Probes profiling interfaces */
878 static int probes_profile_seq_show(struct seq_file
*m
, void *v
)
880 struct trace_kprobe
*tk
= v
;
881 unsigned long nhit
= 0;
884 for_each_possible_cpu(cpu
)
885 nhit
+= *per_cpu_ptr(tk
->nhit
, cpu
);
887 seq_printf(m
, " %-44s %15lu %15lu\n",
888 trace_event_name(&tk
->tp
.call
), nhit
,
894 static const struct seq_operations profile_seq_op
= {
895 .start
= probes_seq_start
,
896 .next
= probes_seq_next
,
897 .stop
= probes_seq_stop
,
898 .show
= probes_profile_seq_show
901 static int profile_open(struct inode
*inode
, struct file
*file
)
903 return seq_open(file
, &profile_seq_op
);
906 static const struct file_operations kprobe_profile_ops
= {
907 .owner
= THIS_MODULE
,
908 .open
= profile_open
,
911 .release
= seq_release
,
915 static nokprobe_inline
void
916 __kprobe_trace_func(struct trace_kprobe
*tk
, struct pt_regs
*regs
,
917 struct trace_event_file
*trace_file
)
919 struct kprobe_trace_entry_head
*entry
;
920 struct ring_buffer_event
*event
;
921 struct ring_buffer
*buffer
;
923 unsigned long irq_flags
;
924 struct trace_event_call
*call
= &tk
->tp
.call
;
926 WARN_ON(call
!= trace_file
->event_call
);
928 if (trace_trigger_soft_disabled(trace_file
))
931 local_save_flags(irq_flags
);
932 pc
= preempt_count();
934 dsize
= __get_data_size(&tk
->tp
, regs
);
935 size
= sizeof(*entry
) + tk
->tp
.size
+ dsize
;
937 event
= trace_event_buffer_lock_reserve(&buffer
, trace_file
,
939 size
, irq_flags
, pc
);
943 entry
= ring_buffer_event_data(event
);
944 entry
->ip
= (unsigned long)tk
->rp
.kp
.addr
;
945 store_trace_args(sizeof(*entry
), &tk
->tp
, regs
, (u8
*)&entry
[1], dsize
);
947 event_trigger_unlock_commit_regs(trace_file
, buffer
, event
,
948 entry
, irq_flags
, pc
, regs
);
952 kprobe_trace_func(struct trace_kprobe
*tk
, struct pt_regs
*regs
)
954 struct event_file_link
*link
;
956 list_for_each_entry_rcu(link
, &tk
->tp
.files
, list
)
957 __kprobe_trace_func(tk
, regs
, link
->file
);
959 NOKPROBE_SYMBOL(kprobe_trace_func
);
961 /* Kretprobe handler */
962 static nokprobe_inline
void
963 __kretprobe_trace_func(struct trace_kprobe
*tk
, struct kretprobe_instance
*ri
,
964 struct pt_regs
*regs
,
965 struct trace_event_file
*trace_file
)
967 struct kretprobe_trace_entry_head
*entry
;
968 struct ring_buffer_event
*event
;
969 struct ring_buffer
*buffer
;
971 unsigned long irq_flags
;
972 struct trace_event_call
*call
= &tk
->tp
.call
;
974 WARN_ON(call
!= trace_file
->event_call
);
976 if (trace_trigger_soft_disabled(trace_file
))
979 local_save_flags(irq_flags
);
980 pc
= preempt_count();
982 dsize
= __get_data_size(&tk
->tp
, regs
);
983 size
= sizeof(*entry
) + tk
->tp
.size
+ dsize
;
985 event
= trace_event_buffer_lock_reserve(&buffer
, trace_file
,
987 size
, irq_flags
, pc
);
991 entry
= ring_buffer_event_data(event
);
992 entry
->func
= (unsigned long)tk
->rp
.kp
.addr
;
993 entry
->ret_ip
= (unsigned long)ri
->ret_addr
;
994 store_trace_args(sizeof(*entry
), &tk
->tp
, regs
, (u8
*)&entry
[1], dsize
);
996 event_trigger_unlock_commit_regs(trace_file
, buffer
, event
,
997 entry
, irq_flags
, pc
, regs
);
1001 kretprobe_trace_func(struct trace_kprobe
*tk
, struct kretprobe_instance
*ri
,
1002 struct pt_regs
*regs
)
1004 struct event_file_link
*link
;
1006 list_for_each_entry_rcu(link
, &tk
->tp
.files
, list
)
1007 __kretprobe_trace_func(tk
, ri
, regs
, link
->file
);
1009 NOKPROBE_SYMBOL(kretprobe_trace_func
);
1011 /* Event entry printers */
1012 static enum print_line_t
1013 print_kprobe_event(struct trace_iterator
*iter
, int flags
,
1014 struct trace_event
*event
)
1016 struct kprobe_trace_entry_head
*field
;
1017 struct trace_seq
*s
= &iter
->seq
;
1018 struct trace_probe
*tp
;
1022 field
= (struct kprobe_trace_entry_head
*)iter
->ent
;
1023 tp
= container_of(event
, struct trace_probe
, call
.event
);
1025 trace_seq_printf(s
, "%s: (", trace_event_name(&tp
->call
));
1027 if (!seq_print_ip_sym(s
, field
->ip
, flags
| TRACE_ITER_SYM_OFFSET
))
1030 trace_seq_putc(s
, ')');
1032 data
= (u8
*)&field
[1];
1033 for (i
= 0; i
< tp
->nr_args
; i
++)
1034 if (!tp
->args
[i
].type
->print(s
, tp
->args
[i
].name
,
1035 data
+ tp
->args
[i
].offset
, field
))
1038 trace_seq_putc(s
, '\n');
1040 return trace_handle_return(s
);
1043 static enum print_line_t
1044 print_kretprobe_event(struct trace_iterator
*iter
, int flags
,
1045 struct trace_event
*event
)
1047 struct kretprobe_trace_entry_head
*field
;
1048 struct trace_seq
*s
= &iter
->seq
;
1049 struct trace_probe
*tp
;
1053 field
= (struct kretprobe_trace_entry_head
*)iter
->ent
;
1054 tp
= container_of(event
, struct trace_probe
, call
.event
);
1056 trace_seq_printf(s
, "%s: (", trace_event_name(&tp
->call
));
1058 if (!seq_print_ip_sym(s
, field
->ret_ip
, flags
| TRACE_ITER_SYM_OFFSET
))
1061 trace_seq_puts(s
, " <- ");
1063 if (!seq_print_ip_sym(s
, field
->func
, flags
& ~TRACE_ITER_SYM_OFFSET
))
1066 trace_seq_putc(s
, ')');
1068 data
= (u8
*)&field
[1];
1069 for (i
= 0; i
< tp
->nr_args
; i
++)
1070 if (!tp
->args
[i
].type
->print(s
, tp
->args
[i
].name
,
1071 data
+ tp
->args
[i
].offset
, field
))
1074 trace_seq_putc(s
, '\n');
1077 return trace_handle_return(s
);
1081 static int kprobe_event_define_fields(struct trace_event_call
*event_call
)
1084 struct kprobe_trace_entry_head field
;
1085 struct trace_kprobe
*tk
= (struct trace_kprobe
*)event_call
->data
;
1087 DEFINE_FIELD(unsigned long, ip
, FIELD_STRING_IP
, 0);
1088 /* Set argument names as fields */
1089 for (i
= 0; i
< tk
->tp
.nr_args
; i
++) {
1090 struct probe_arg
*parg
= &tk
->tp
.args
[i
];
1092 ret
= trace_define_field(event_call
, parg
->type
->fmttype
,
1094 sizeof(field
) + parg
->offset
,
1096 parg
->type
->is_signed
,
1104 static int kretprobe_event_define_fields(struct trace_event_call
*event_call
)
1107 struct kretprobe_trace_entry_head field
;
1108 struct trace_kprobe
*tk
= (struct trace_kprobe
*)event_call
->data
;
1110 DEFINE_FIELD(unsigned long, func
, FIELD_STRING_FUNC
, 0);
1111 DEFINE_FIELD(unsigned long, ret_ip
, FIELD_STRING_RETIP
, 0);
1112 /* Set argument names as fields */
1113 for (i
= 0; i
< tk
->tp
.nr_args
; i
++) {
1114 struct probe_arg
*parg
= &tk
->tp
.args
[i
];
1116 ret
= trace_define_field(event_call
, parg
->type
->fmttype
,
1118 sizeof(field
) + parg
->offset
,
1120 parg
->type
->is_signed
,
1128 #ifdef CONFIG_PERF_EVENTS
1130 /* Kprobe profile handler */
1132 kprobe_perf_func(struct trace_kprobe
*tk
, struct pt_regs
*regs
)
1134 struct trace_event_call
*call
= &tk
->tp
.call
;
1135 struct bpf_prog
*prog
= call
->prog
;
1136 struct kprobe_trace_entry_head
*entry
;
1137 struct hlist_head
*head
;
1138 int size
, __size
, dsize
;
1141 if (prog
&& !trace_call_bpf(prog
, regs
))
1144 head
= this_cpu_ptr(call
->perf_events
);
1145 if (hlist_empty(head
))
1148 dsize
= __get_data_size(&tk
->tp
, regs
);
1149 __size
= sizeof(*entry
) + tk
->tp
.size
+ dsize
;
1150 size
= ALIGN(__size
+ sizeof(u32
), sizeof(u64
));
1151 size
-= sizeof(u32
);
1153 entry
= perf_trace_buf_alloc(size
, NULL
, &rctx
);
1157 entry
->ip
= (unsigned long)tk
->rp
.kp
.addr
;
1158 memset(&entry
[1], 0, dsize
);
1159 store_trace_args(sizeof(*entry
), &tk
->tp
, regs
, (u8
*)&entry
[1], dsize
);
1160 perf_trace_buf_submit(entry
, size
, rctx
, call
->event
.type
, 1, regs
,
1163 NOKPROBE_SYMBOL(kprobe_perf_func
);
1165 /* Kretprobe profile handler */
1167 kretprobe_perf_func(struct trace_kprobe
*tk
, struct kretprobe_instance
*ri
,
1168 struct pt_regs
*regs
)
1170 struct trace_event_call
*call
= &tk
->tp
.call
;
1171 struct bpf_prog
*prog
= call
->prog
;
1172 struct kretprobe_trace_entry_head
*entry
;
1173 struct hlist_head
*head
;
1174 int size
, __size
, dsize
;
1177 if (prog
&& !trace_call_bpf(prog
, regs
))
1180 head
= this_cpu_ptr(call
->perf_events
);
1181 if (hlist_empty(head
))
1184 dsize
= __get_data_size(&tk
->tp
, regs
);
1185 __size
= sizeof(*entry
) + tk
->tp
.size
+ dsize
;
1186 size
= ALIGN(__size
+ sizeof(u32
), sizeof(u64
));
1187 size
-= sizeof(u32
);
1189 entry
= perf_trace_buf_alloc(size
, NULL
, &rctx
);
1193 entry
->func
= (unsigned long)tk
->rp
.kp
.addr
;
1194 entry
->ret_ip
= (unsigned long)ri
->ret_addr
;
1195 store_trace_args(sizeof(*entry
), &tk
->tp
, regs
, (u8
*)&entry
[1], dsize
);
1196 perf_trace_buf_submit(entry
, size
, rctx
, call
->event
.type
, 1, regs
,
1199 NOKPROBE_SYMBOL(kretprobe_perf_func
);
1200 #endif /* CONFIG_PERF_EVENTS */
1203 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1205 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1206 * lockless, but we can't race with this __init function.
1208 static int kprobe_register(struct trace_event_call
*event
,
1209 enum trace_reg type
, void *data
)
1211 struct trace_kprobe
*tk
= (struct trace_kprobe
*)event
->data
;
1212 struct trace_event_file
*file
= data
;
1215 case TRACE_REG_REGISTER
:
1216 return enable_trace_kprobe(tk
, file
);
1217 case TRACE_REG_UNREGISTER
:
1218 return disable_trace_kprobe(tk
, file
);
1220 #ifdef CONFIG_PERF_EVENTS
1221 case TRACE_REG_PERF_REGISTER
:
1222 return enable_trace_kprobe(tk
, NULL
);
1223 case TRACE_REG_PERF_UNREGISTER
:
1224 return disable_trace_kprobe(tk
, NULL
);
1225 case TRACE_REG_PERF_OPEN
:
1226 case TRACE_REG_PERF_CLOSE
:
1227 case TRACE_REG_PERF_ADD
:
1228 case TRACE_REG_PERF_DEL
:
1235 static int kprobe_dispatcher(struct kprobe
*kp
, struct pt_regs
*regs
)
1237 struct trace_kprobe
*tk
= container_of(kp
, struct trace_kprobe
, rp
.kp
);
1239 raw_cpu_inc(*tk
->nhit
);
1241 if (tk
->tp
.flags
& TP_FLAG_TRACE
)
1242 kprobe_trace_func(tk
, regs
);
1243 #ifdef CONFIG_PERF_EVENTS
1244 if (tk
->tp
.flags
& TP_FLAG_PROFILE
)
1245 kprobe_perf_func(tk
, regs
);
1247 return 0; /* We don't tweek kernel, so just return 0 */
1249 NOKPROBE_SYMBOL(kprobe_dispatcher
);
1252 kretprobe_dispatcher(struct kretprobe_instance
*ri
, struct pt_regs
*regs
)
1254 struct trace_kprobe
*tk
= container_of(ri
->rp
, struct trace_kprobe
, rp
);
1256 raw_cpu_inc(*tk
->nhit
);
1258 if (tk
->tp
.flags
& TP_FLAG_TRACE
)
1259 kretprobe_trace_func(tk
, ri
, regs
);
1260 #ifdef CONFIG_PERF_EVENTS
1261 if (tk
->tp
.flags
& TP_FLAG_PROFILE
)
1262 kretprobe_perf_func(tk
, ri
, regs
);
1264 return 0; /* We don't tweek kernel, so just return 0 */
1266 NOKPROBE_SYMBOL(kretprobe_dispatcher
);
1268 static struct trace_event_functions kretprobe_funcs
= {
1269 .trace
= print_kretprobe_event
1272 static struct trace_event_functions kprobe_funcs
= {
1273 .trace
= print_kprobe_event
1276 static int register_kprobe_event(struct trace_kprobe
*tk
)
1278 struct trace_event_call
*call
= &tk
->tp
.call
;
1281 /* Initialize trace_event_call */
1282 INIT_LIST_HEAD(&call
->class->fields
);
1283 if (trace_kprobe_is_return(tk
)) {
1284 call
->event
.funcs
= &kretprobe_funcs
;
1285 call
->class->define_fields
= kretprobe_event_define_fields
;
1287 call
->event
.funcs
= &kprobe_funcs
;
1288 call
->class->define_fields
= kprobe_event_define_fields
;
1290 if (set_print_fmt(&tk
->tp
, trace_kprobe_is_return(tk
)) < 0)
1292 ret
= register_trace_event(&call
->event
);
1294 kfree(call
->print_fmt
);
1297 call
->flags
= TRACE_EVENT_FL_KPROBE
;
1298 call
->class->reg
= kprobe_register
;
1300 ret
= trace_add_event_call(call
);
1302 pr_info("Failed to register kprobe event: %s\n",
1303 trace_event_name(call
));
1304 kfree(call
->print_fmt
);
1305 unregister_trace_event(&call
->event
);
1310 static int unregister_kprobe_event(struct trace_kprobe
*tk
)
1314 /* tp->event is unregistered in trace_remove_event_call() */
1315 ret
= trace_remove_event_call(&tk
->tp
.call
);
1317 kfree(tk
->tp
.call
.print_fmt
);
1321 /* Make a tracefs interface for controlling probe points */
1322 static __init
int init_kprobe_trace(void)
1324 struct dentry
*d_tracer
;
1325 struct dentry
*entry
;
1327 if (register_module_notifier(&trace_kprobe_module_nb
))
1330 d_tracer
= tracing_init_dentry();
1331 if (IS_ERR(d_tracer
))
1334 entry
= tracefs_create_file("kprobe_events", 0644, d_tracer
,
1335 NULL
, &kprobe_events_ops
);
1337 /* Event list interface */
1339 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1341 /* Profile interface */
1342 entry
= tracefs_create_file("kprobe_profile", 0444, d_tracer
,
1343 NULL
, &kprobe_profile_ops
);
1346 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1349 fs_initcall(init_kprobe_trace
);
1352 #ifdef CONFIG_FTRACE_STARTUP_TEST
1355 * The "__used" keeps gcc from removing the function symbol
1356 * from the kallsyms table.
1358 static __used
int kprobe_trace_selftest_target(int a1
, int a2
, int a3
,
1359 int a4
, int a5
, int a6
)
1361 return a1
+ a2
+ a3
+ a4
+ a5
+ a6
;
1364 static struct trace_event_file
*
1365 find_trace_probe_file(struct trace_kprobe
*tk
, struct trace_array
*tr
)
1367 struct trace_event_file
*file
;
1369 list_for_each_entry(file
, &tr
->events
, list
)
1370 if (file
->event_call
== &tk
->tp
.call
)
1377 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1378 * stage, we can do this lockless.
1380 static __init
int kprobe_trace_self_tests_init(void)
1383 int (*target
)(int, int, int, int, int, int);
1384 struct trace_kprobe
*tk
;
1385 struct trace_event_file
*file
;
1387 if (tracing_is_disabled())
1390 target
= kprobe_trace_selftest_target
;
1392 pr_info("Testing kprobe tracing: ");
1394 ret
= traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1395 "$stack $stack0 +0($stack)",
1396 create_trace_kprobe
);
1397 if (WARN_ON_ONCE(ret
)) {
1398 pr_warn("error on probing function entry.\n");
1401 /* Enable trace point */
1402 tk
= find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM
);
1403 if (WARN_ON_ONCE(tk
== NULL
)) {
1404 pr_warn("error on getting new probe.\n");
1407 file
= find_trace_probe_file(tk
, top_trace_array());
1408 if (WARN_ON_ONCE(file
== NULL
)) {
1409 pr_warn("error on getting probe file.\n");
1412 enable_trace_kprobe(tk
, file
);
1416 ret
= traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1417 "$retval", create_trace_kprobe
);
1418 if (WARN_ON_ONCE(ret
)) {
1419 pr_warn("error on probing function return.\n");
1422 /* Enable trace point */
1423 tk
= find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM
);
1424 if (WARN_ON_ONCE(tk
== NULL
)) {
1425 pr_warn("error on getting 2nd new probe.\n");
1428 file
= find_trace_probe_file(tk
, top_trace_array());
1429 if (WARN_ON_ONCE(file
== NULL
)) {
1430 pr_warn("error on getting probe file.\n");
1433 enable_trace_kprobe(tk
, file
);
1440 ret
= target(1, 2, 3, 4, 5, 6);
1442 /* Disable trace points before removing it */
1443 tk
= find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM
);
1444 if (WARN_ON_ONCE(tk
== NULL
)) {
1445 pr_warn("error on getting test probe.\n");
1448 file
= find_trace_probe_file(tk
, top_trace_array());
1449 if (WARN_ON_ONCE(file
== NULL
)) {
1450 pr_warn("error on getting probe file.\n");
1453 disable_trace_kprobe(tk
, file
);
1456 tk
= find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM
);
1457 if (WARN_ON_ONCE(tk
== NULL
)) {
1458 pr_warn("error on getting 2nd test probe.\n");
1461 file
= find_trace_probe_file(tk
, top_trace_array());
1462 if (WARN_ON_ONCE(file
== NULL
)) {
1463 pr_warn("error on getting probe file.\n");
1466 disable_trace_kprobe(tk
, file
);
1469 ret
= traceprobe_command("-:testprobe", create_trace_kprobe
);
1470 if (WARN_ON_ONCE(ret
)) {
1471 pr_warn("error on deleting a probe.\n");
1475 ret
= traceprobe_command("-:testprobe2", create_trace_kprobe
);
1476 if (WARN_ON_ONCE(ret
)) {
1477 pr_warn("error on deleting a probe.\n");
1482 release_all_trace_kprobes();
1484 pr_cont("NG: Some tests are failed. Please check them.\n");
1490 late_initcall(kprobe_trace_self_tests_init
);