// SPDX-License-Identifier: GPL-2.0
|
/*
|
* Kprobes-based tracing events
|
*
|
* Created by Masami Hiramatsu <mhiramat@redhat.com>
|
*
|
*/
|
#define pr_fmt(fmt) "trace_kprobe: " fmt
|
|
#include <linux/security.h>
|
#include <linux/module.h>
|
#include <linux/uaccess.h>
|
#include <linux/rculist.h>
|
#include <linux/error-injection.h>
|
|
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
|
|
#include "trace_dynevent.h"
|
#include "trace_kprobe_selftest.h"
|
#include "trace_probe.h"
|
#include "trace_probe_tmpl.h"
|
|
#define KPROBE_EVENT_SYSTEM "kprobes"
|
#define KRETPROBE_MAXACTIVE_MAX 4096
|
|
/* Kprobe early definition from command line */
|
static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
|
|
static int __init set_kprobe_boot_events(char *str)
|
{
|
strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
|
disable_tracing_selftest("running kprobe events");
|
|
return 1;
|
}
|
__setup("kprobe_event=", set_kprobe_boot_events);
|
|
static int trace_kprobe_create(int argc, const char **argv);
|
static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
|
static int trace_kprobe_release(struct dyn_event *ev);
|
static bool trace_kprobe_is_busy(struct dyn_event *ev);
|
static bool trace_kprobe_match(const char *system, const char *event,
|
int argc, const char **argv, struct dyn_event *ev);
|
|
static struct dyn_event_operations trace_kprobe_ops = {
|
.create = trace_kprobe_create,
|
.show = trace_kprobe_show,
|
.is_busy = trace_kprobe_is_busy,
|
.free = trace_kprobe_release,
|
.match = trace_kprobe_match,
|
};
|
|
/*
|
* Kprobe event core functions
|
*/
|
struct trace_kprobe {
|
struct dyn_event devent;
|
struct kretprobe rp; /* Use rp.kp for kprobe use */
|
unsigned long __percpu *nhit;
|
const char *symbol; /* symbol name */
|
struct trace_probe tp;
|
};
|
|
static bool is_trace_kprobe(struct dyn_event *ev)
|
{
|
return ev->ops == &trace_kprobe_ops;
|
}
|
|
static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
|
{
|
return container_of(ev, struct trace_kprobe, devent);
|
}
|
|
/**
|
* for_each_trace_kprobe - iterate over the trace_kprobe list
|
* @pos: the struct trace_kprobe * for each entry
|
* @dpos: the struct dyn_event * to use as a loop cursor
|
*/
|
#define for_each_trace_kprobe(pos, dpos) \
|
for_each_dyn_event(dpos) \
|
if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
|
|
#define SIZEOF_TRACE_KPROBE(n) \
|
(offsetof(struct trace_kprobe, tp.args) + \
|
(sizeof(struct probe_arg) * (n)))
|
|
static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
|
{
|
return tk->rp.handler != NULL;
|
}
|
|
static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
|
{
|
return tk->symbol ? tk->symbol : "unknown";
|
}
|
|
static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
|
{
|
return tk->rp.kp.offset;
|
}
|
|
static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
|
{
|
return !!(kprobe_gone(&tk->rp.kp));
|
}
|
|
static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
|
struct module *mod)
|
{
|
int len = strlen(module_name(mod));
|
const char *name = trace_kprobe_symbol(tk);
|
|
return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
|
}
|
|
static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
|
{
|
char *p;
|
bool ret;
|
|
if (!tk->symbol)
|
return false;
|
p = strchr(tk->symbol, ':');
|
if (!p)
|
return true;
|
*p = '\0';
|
mutex_lock(&module_mutex);
|
ret = !!find_module(tk->symbol);
|
mutex_unlock(&module_mutex);
|
*p = ':';
|
|
return ret;
|
}
|
|
static bool trace_kprobe_is_busy(struct dyn_event *ev)
|
{
|
struct trace_kprobe *tk = to_trace_kprobe(ev);
|
|
return trace_probe_is_enabled(&tk->tp);
|
}
|
|
static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
|
int argc, const char **argv)
|
{
|
char buf[MAX_ARGSTR_LEN + 1];
|
|
if (!argc)
|
return true;
|
|
if (!tk->symbol)
|
snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
|
else if (tk->rp.kp.offset)
|
snprintf(buf, sizeof(buf), "%s+%u",
|
trace_kprobe_symbol(tk), tk->rp.kp.offset);
|
else
|
snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
|
if (strcmp(buf, argv[0]))
|
return false;
|
argc--; argv++;
|
|
return trace_probe_match_command_args(&tk->tp, argc, argv);
|
}
|
|
static bool trace_kprobe_match(const char *system, const char *event,
|
int argc, const char **argv, struct dyn_event *ev)
|
{
|
struct trace_kprobe *tk = to_trace_kprobe(ev);
|
|
return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
|
(!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
|
trace_kprobe_match_command_head(tk, argc, argv);
|
}
|
|
static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
|
{
|
unsigned long nhit = 0;
|
int cpu;
|
|
for_each_possible_cpu(cpu)
|
nhit += *per_cpu_ptr(tk->nhit, cpu);
|
|
return nhit;
|
}
|
|
static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
|
{
|
return !(list_empty(&tk->rp.kp.list) &&
|
hlist_unhashed(&tk->rp.kp.hlist));
|
}
|
|
/* Return 0 if it fails to find the symbol address */
|
static nokprobe_inline
|
unsigned long trace_kprobe_address(struct trace_kprobe *tk)
|
{
|
unsigned long addr;
|
|
if (tk->symbol) {
|
addr = (unsigned long)
|
kallsyms_lookup_name(trace_kprobe_symbol(tk));
|
if (addr)
|
addr += tk->rp.kp.offset;
|
} else {
|
addr = (unsigned long)tk->rp.kp.addr;
|
}
|
return addr;
|
}
|
|
static nokprobe_inline struct trace_kprobe *
|
trace_kprobe_primary_from_call(struct trace_event_call *call)
|
{
|
struct trace_probe *tp;
|
|
tp = trace_probe_primary_from_call(call);
|
if (WARN_ON_ONCE(!tp))
|
return NULL;
|
|
return container_of(tp, struct trace_kprobe, tp);
|
}
|
|
bool trace_kprobe_on_func_entry(struct trace_event_call *call)
|
{
|
struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
|
|
return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
|
tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
|
tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
|
}
|
|
bool trace_kprobe_error_injectable(struct trace_event_call *call)
|
{
|
struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
|
|
return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
|
false;
|
}
|
|
static int register_kprobe_event(struct trace_kprobe *tk);
|
static int unregister_kprobe_event(struct trace_kprobe *tk);
|
|
static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
|
static int kretprobe_dispatcher(struct kretprobe_instance *ri,
|
struct pt_regs *regs);
|
|
static void free_trace_kprobe(struct trace_kprobe *tk)
|
{
|
if (tk) {
|
trace_probe_cleanup(&tk->tp);
|
kfree(tk->symbol);
|
free_percpu(tk->nhit);
|
kfree(tk);
|
}
|
}
|
|
/*
|
* Allocate new trace_probe and initialize it (including kprobes).
|
*/
|
static struct trace_kprobe *alloc_trace_kprobe(const char *group,
|
const char *event,
|
void *addr,
|
const char *symbol,
|
unsigned long offs,
|
int maxactive,
|
int nargs, bool is_return)
|
{
|
struct trace_kprobe *tk;
|
int ret = -ENOMEM;
|
|
tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
|
if (!tk)
|
return ERR_PTR(ret);
|
|
tk->nhit = alloc_percpu(unsigned long);
|
if (!tk->nhit)
|
goto error;
|
|
if (symbol) {
|
tk->symbol = kstrdup(symbol, GFP_KERNEL);
|
if (!tk->symbol)
|
goto error;
|
tk->rp.kp.symbol_name = tk->symbol;
|
tk->rp.kp.offset = offs;
|
} else
|
tk->rp.kp.addr = addr;
|
|
if (is_return)
|
tk->rp.handler = kretprobe_dispatcher;
|
else
|
tk->rp.kp.pre_handler = kprobe_dispatcher;
|
|
tk->rp.maxactive = maxactive;
|
INIT_HLIST_NODE(&tk->rp.kp.hlist);
|
INIT_LIST_HEAD(&tk->rp.kp.list);
|
|
ret = trace_probe_init(&tk->tp, event, group, false);
|
if (ret < 0)
|
goto error;
|
|
dyn_event_init(&tk->devent, &trace_kprobe_ops);
|
return tk;
|
error:
|
free_trace_kprobe(tk);
|
return ERR_PTR(ret);
|
}
|
|
static struct trace_kprobe *find_trace_kprobe(const char *event,
|
const char *group)
|
{
|
struct dyn_event *pos;
|
struct trace_kprobe *tk;
|
|
for_each_trace_kprobe(tk, pos)
|
if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
|
strcmp(trace_probe_group_name(&tk->tp), group) == 0)
|
return tk;
|
return NULL;
|
}
|
|
static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
|
{
|
int ret = 0;
|
|
if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
|
if (trace_kprobe_is_return(tk))
|
ret = enable_kretprobe(&tk->rp);
|
else
|
ret = enable_kprobe(&tk->rp.kp);
|
}
|
|
return ret;
|
}
|
|
static void __disable_trace_kprobe(struct trace_probe *tp)
|
{
|
struct trace_probe *pos;
|
struct trace_kprobe *tk;
|
|
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
|
tk = container_of(pos, struct trace_kprobe, tp);
|
if (!trace_kprobe_is_registered(tk))
|
continue;
|
if (trace_kprobe_is_return(tk))
|
disable_kretprobe(&tk->rp);
|
else
|
disable_kprobe(&tk->rp.kp);
|
}
|
}
|
|
/*
|
* Enable trace_probe
|
* if the file is NULL, enable "perf" handler, or enable "trace" handler.
|
*/
|
static int enable_trace_kprobe(struct trace_event_call *call,
|
struct trace_event_file *file)
|
{
|
struct trace_probe *pos, *tp;
|
struct trace_kprobe *tk;
|
bool enabled;
|
int ret = 0;
|
|
tp = trace_probe_primary_from_call(call);
|
if (WARN_ON_ONCE(!tp))
|
return -ENODEV;
|
enabled = trace_probe_is_enabled(tp);
|
|
/* This also changes "enabled" state */
|
if (file) {
|
ret = trace_probe_add_file(tp, file);
|
if (ret)
|
return ret;
|
} else
|
trace_probe_set_flag(tp, TP_FLAG_PROFILE);
|
|
if (enabled)
|
return 0;
|
|
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
|
tk = container_of(pos, struct trace_kprobe, tp);
|
if (trace_kprobe_has_gone(tk))
|
continue;
|
ret = __enable_trace_kprobe(tk);
|
if (ret)
|
break;
|
enabled = true;
|
}
|
|
if (ret) {
|
/* Failed to enable one of them. Roll back all */
|
if (enabled)
|
__disable_trace_kprobe(tp);
|
if (file)
|
trace_probe_remove_file(tp, file);
|
else
|
trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
|
}
|
|
return ret;
|
}
|
|
/*
|
* Disable trace_probe
|
* if the file is NULL, disable "perf" handler, or disable "trace" handler.
|
*/
|
static int disable_trace_kprobe(struct trace_event_call *call,
|
struct trace_event_file *file)
|
{
|
struct trace_probe *tp;
|
|
tp = trace_probe_primary_from_call(call);
|
if (WARN_ON_ONCE(!tp))
|
return -ENODEV;
|
|
if (file) {
|
if (!trace_probe_get_file_link(tp, file))
|
return -ENOENT;
|
if (!trace_probe_has_single_file(tp))
|
goto out;
|
trace_probe_clear_flag(tp, TP_FLAG_TRACE);
|
} else
|
trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
|
|
if (!trace_probe_is_enabled(tp))
|
__disable_trace_kprobe(tp);
|
|
out:
|
if (file)
|
/*
|
* Synchronization is done in below function. For perf event,
|
* file == NULL and perf_trace_event_unreg() calls
|
* tracepoint_synchronize_unregister() to ensure synchronize
|
* event. We don't need to care about it.
|
*/
|
trace_probe_remove_file(tp, file);
|
|
return 0;
|
}
|
|
#if defined(CONFIG_DYNAMIC_FTRACE) && \
|
!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
|
static bool __within_notrace_func(unsigned long addr)
|
{
|
unsigned long offset, size;
|
|
if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
|
return false;
|
|
/* Get the entry address of the target function */
|
addr -= offset;
|
|
/*
|
* Since ftrace_location_range() does inclusive range check, we need
|
* to subtract 1 byte from the end address.
|
*/
|
return !ftrace_location_range(addr, addr + size - 1);
|
}
|
|
static bool within_notrace_func(struct trace_kprobe *tk)
|
{
|
unsigned long addr = trace_kprobe_address(tk);
|
char symname[KSYM_NAME_LEN], *p;
|
|
if (!__within_notrace_func(addr))
|
return false;
|
|
/* Check if the address is on a suffixed-symbol */
|
if (!lookup_symbol_name(addr, symname)) {
|
p = strchr(symname, '.');
|
if (!p)
|
return true;
|
*p = '\0';
|
addr = (unsigned long)kprobe_lookup_name(symname, 0);
|
if (addr)
|
return __within_notrace_func(addr);
|
}
|
|
return true;
|
}
|
#else
|
#define within_notrace_func(tk) (false)
|
#endif
|
|
/* Internal register function - just handle k*probes and flags */
|
static int __register_trace_kprobe(struct trace_kprobe *tk)
|
{
|
int i, ret;
|
|
ret = security_locked_down(LOCKDOWN_KPROBES);
|
if (ret)
|
return ret;
|
|
if (trace_kprobe_is_registered(tk))
|
return -EINVAL;
|
|
if (within_notrace_func(tk)) {
|
pr_warn("Could not probe notrace function %s\n",
|
trace_kprobe_symbol(tk));
|
return -EINVAL;
|
}
|
|
for (i = 0; i < tk->tp.nr_args; i++) {
|
ret = traceprobe_update_arg(&tk->tp.args[i]);
|
if (ret)
|
return ret;
|
}
|
|
/* Set/clear disabled flag according to tp->flag */
|
if (trace_probe_is_enabled(&tk->tp))
|
tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
|
else
|
tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
|
|
if (trace_kprobe_is_return(tk))
|
ret = register_kretprobe(&tk->rp);
|
else
|
ret = register_kprobe(&tk->rp.kp);
|
|
return ret;
|
}
|
|
/* Internal unregister function - just handle k*probes and flags */
|
static void __unregister_trace_kprobe(struct trace_kprobe *tk)
|
{
|
if (trace_kprobe_is_registered(tk)) {
|
if (trace_kprobe_is_return(tk))
|
unregister_kretprobe(&tk->rp);
|
else
|
unregister_kprobe(&tk->rp.kp);
|
/* Cleanup kprobe for reuse and mark it unregistered */
|
INIT_HLIST_NODE(&tk->rp.kp.hlist);
|
INIT_LIST_HEAD(&tk->rp.kp.list);
|
if (tk->rp.kp.symbol_name)
|
tk->rp.kp.addr = NULL;
|
}
|
}
|
|
/* Unregister a trace_probe and probe_event */
|
static int unregister_trace_kprobe(struct trace_kprobe *tk)
|
{
|
/* If other probes are on the event, just unregister kprobe */
|
if (trace_probe_has_sibling(&tk->tp))
|
goto unreg;
|
|
/* Enabled event can not be unregistered */
|
if (trace_probe_is_enabled(&tk->tp))
|
return -EBUSY;
|
|
/* Will fail if probe is being used by ftrace or perf */
|
if (unregister_kprobe_event(tk))
|
return -EBUSY;
|
|
unreg:
|
__unregister_trace_kprobe(tk);
|
dyn_event_remove(&tk->devent);
|
trace_probe_unlink(&tk->tp);
|
|
return 0;
|
}
|
|
static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
|
struct trace_kprobe *comp)
|
{
|
struct trace_probe_event *tpe = orig->tp.event;
|
struct trace_probe *pos;
|
int i;
|
|
list_for_each_entry(pos, &tpe->probes, list) {
|
orig = container_of(pos, struct trace_kprobe, tp);
|
if (strcmp(trace_kprobe_symbol(orig),
|
trace_kprobe_symbol(comp)) ||
|
trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
|
continue;
|
|
/*
|
* trace_probe_compare_arg_type() ensured that nr_args and
|
* each argument name and type are same. Let's compare comm.
|
*/
|
for (i = 0; i < orig->tp.nr_args; i++) {
|
if (strcmp(orig->tp.args[i].comm,
|
comp->tp.args[i].comm))
|
break;
|
}
|
|
if (i == orig->tp.nr_args)
|
return true;
|
}
|
|
return false;
|
}
|
|
static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
|
{
|
int ret;
|
|
ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
|
if (ret) {
|
/* Note that argument starts index = 2 */
|
trace_probe_log_set_index(ret + 1);
|
trace_probe_log_err(0, DIFF_ARG_TYPE);
|
return -EEXIST;
|
}
|
if (trace_kprobe_has_same_kprobe(to, tk)) {
|
trace_probe_log_set_index(0);
|
trace_probe_log_err(0, SAME_PROBE);
|
return -EEXIST;
|
}
|
|
/* Append to existing event */
|
ret = trace_probe_append(&tk->tp, &to->tp);
|
if (ret)
|
return ret;
|
|
/* Register k*probe */
|
ret = __register_trace_kprobe(tk);
|
if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
|
pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
|
ret = 0;
|
}
|
|
if (ret)
|
trace_probe_unlink(&tk->tp);
|
else
|
dyn_event_add(&tk->devent);
|
|
return ret;
|
}
|
|
/* Register a trace_probe and probe_event */
|
static int register_trace_kprobe(struct trace_kprobe *tk)
|
{
|
struct trace_kprobe *old_tk;
|
int ret;
|
|
mutex_lock(&event_mutex);
|
|
old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
|
trace_probe_group_name(&tk->tp));
|
if (old_tk) {
|
if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
|
trace_probe_log_set_index(0);
|
trace_probe_log_err(0, DIFF_PROBE_TYPE);
|
ret = -EEXIST;
|
} else {
|
ret = append_trace_kprobe(tk, old_tk);
|
}
|
goto end;
|
}
|
|
/* Register new event */
|
ret = register_kprobe_event(tk);
|
if (ret) {
|
if (ret == -EEXIST) {
|
trace_probe_log_set_index(0);
|
trace_probe_log_err(0, EVENT_EXIST);
|
} else
|
pr_warn("Failed to register probe event(%d)\n", ret);
|
goto end;
|
}
|
|
/* Register k*probe */
|
ret = __register_trace_kprobe(tk);
|
if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
|
pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
|
ret = 0;
|
}
|
|
if (ret < 0)
|
unregister_kprobe_event(tk);
|
else
|
dyn_event_add(&tk->devent);
|
|
end:
|
mutex_unlock(&event_mutex);
|
return ret;
|
}
|
|
/* Module notifier call back, checking event on the module */
|
static int trace_kprobe_module_callback(struct notifier_block *nb,
|
unsigned long val, void *data)
|
{
|
struct module *mod = data;
|
struct dyn_event *pos;
|
struct trace_kprobe *tk;
|
int ret;
|
|
if (val != MODULE_STATE_COMING)
|
return NOTIFY_DONE;
|
|
/* Update probes on coming module */
|
mutex_lock(&event_mutex);
|
for_each_trace_kprobe(tk, pos) {
|
if (trace_kprobe_within_module(tk, mod)) {
|
/* Don't need to check busy - this should have gone. */
|
__unregister_trace_kprobe(tk);
|
ret = __register_trace_kprobe(tk);
|
if (ret)
|
pr_warn("Failed to re-register probe %s on %s: %d\n",
|
trace_probe_name(&tk->tp),
|
module_name(mod), ret);
|
}
|
}
|
mutex_unlock(&event_mutex);
|
|
return NOTIFY_DONE;
|
}
|
|
static struct notifier_block trace_kprobe_module_nb = {
|
.notifier_call = trace_kprobe_module_callback,
|
.priority = 1 /* Invoked after kprobe module callback */
|
};
|
|
/* Convert certain expected symbols into '_' when generating event names */
|
static inline void sanitize_event_name(char *name)
|
{
|
while (*name++ != '\0')
|
if (*name == ':' || *name == '.')
|
*name = '_';
|
}
|
|
static int trace_kprobe_create(int argc, const char *argv[])
|
{
|
/*
|
* Argument syntax:
|
* - Add kprobe:
|
* p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
|
* - Add kretprobe:
|
* r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
|
* Or
|
* p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS]
|
*
|
* Fetch args:
|
* $retval : fetch return value
|
* $stack : fetch stack address
|
* $stackN : fetch Nth of stack (N:0-)
|
* $comm : fetch current task comm
|
* @ADDR : fetch memory at ADDR (ADDR should be in kernel)
|
* @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
|
* %REG : fetch register REG
|
* Dereferencing memory fetch:
|
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
|
* Alias name of args:
|
* NAME=FETCHARG : set NAME as alias of FETCHARG.
|
* Type of args:
|
* FETCHARG:TYPE : use TYPE instead of unsigned long.
|
*/
|
struct trace_kprobe *tk = NULL;
|
int i, len, ret = 0;
|
bool is_return = false;
|
char *symbol = NULL, *tmp = NULL;
|
const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
|
int maxactive = 0;
|
long offset = 0;
|
void *addr = NULL;
|
char buf[MAX_EVENT_NAME_LEN];
|
unsigned int flags = TPARG_FL_KERNEL;
|
|
switch (argv[0][0]) {
|
case 'r':
|
is_return = true;
|
break;
|
case 'p':
|
break;
|
default:
|
return -ECANCELED;
|
}
|
if (argc < 2)
|
return -ECANCELED;
|
|
trace_probe_log_init("trace_kprobe", argc, argv);
|
|
event = strchr(&argv[0][1], ':');
|
if (event)
|
event++;
|
|
if (isdigit(argv[0][1])) {
|
if (!is_return) {
|
trace_probe_log_err(1, MAXACT_NO_KPROBE);
|
goto parse_error;
|
}
|
if (event)
|
len = event - &argv[0][1] - 1;
|
else
|
len = strlen(&argv[0][1]);
|
if (len > MAX_EVENT_NAME_LEN - 1) {
|
trace_probe_log_err(1, BAD_MAXACT);
|
goto parse_error;
|
}
|
memcpy(buf, &argv[0][1], len);
|
buf[len] = '\0';
|
ret = kstrtouint(buf, 0, &maxactive);
|
if (ret || !maxactive) {
|
trace_probe_log_err(1, BAD_MAXACT);
|
goto parse_error;
|
}
|
/* kretprobes instances are iterated over via a list. The
|
* maximum should stay reasonable.
|
*/
|
if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
|
trace_probe_log_err(1, MAXACT_TOO_BIG);
|
goto parse_error;
|
}
|
}
|
|
/* try to parse an address. if that fails, try to read the
|
* input as a symbol. */
|
if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
|
trace_probe_log_set_index(1);
|
/* Check whether uprobe event specified */
|
if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
|
ret = -ECANCELED;
|
goto error;
|
}
|
/* a symbol specified */
|
symbol = kstrdup(argv[1], GFP_KERNEL);
|
if (!symbol)
|
return -ENOMEM;
|
|
tmp = strchr(symbol, '%');
|
if (tmp) {
|
if (!strcmp(tmp, "%return")) {
|
*tmp = '\0';
|
is_return = true;
|
} else {
|
trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
|
goto parse_error;
|
}
|
}
|
|
/* TODO: support .init module functions */
|
ret = traceprobe_split_symbol_offset(symbol, &offset);
|
if (ret || offset < 0 || offset > UINT_MAX) {
|
trace_probe_log_err(0, BAD_PROBE_ADDR);
|
goto parse_error;
|
}
|
if (is_return)
|
flags |= TPARG_FL_RETURN;
|
ret = kprobe_on_func_entry(NULL, symbol, offset);
|
if (ret == 0)
|
flags |= TPARG_FL_FENTRY;
|
/* Defer the ENOENT case until register kprobe */
|
if (ret == -EINVAL && is_return) {
|
trace_probe_log_err(0, BAD_RETPROBE);
|
goto parse_error;
|
}
|
}
|
|
trace_probe_log_set_index(0);
|
if (event) {
|
ret = traceprobe_parse_event_name(&event, &group, buf,
|
event - argv[0]);
|
if (ret)
|
goto parse_error;
|
} else {
|
/* Make a new event name */
|
if (symbol)
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
|
is_return ? 'r' : 'p', symbol, offset);
|
else
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
|
is_return ? 'r' : 'p', addr);
|
sanitize_event_name(buf);
|
event = buf;
|
}
|
|
/* setup a probe */
|
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
|
argc - 2, is_return);
|
if (IS_ERR(tk)) {
|
ret = PTR_ERR(tk);
|
/* This must return -ENOMEM, else there is a bug */
|
WARN_ON_ONCE(ret != -ENOMEM);
|
goto out; /* We know tk is not allocated */
|
}
|
argc -= 2; argv += 2;
|
|
/* parse arguments */
|
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
|
tmp = kstrdup(argv[i], GFP_KERNEL);
|
if (!tmp) {
|
ret = -ENOMEM;
|
goto error;
|
}
|
|
trace_probe_log_set_index(i + 2);
|
ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
|
kfree(tmp);
|
if (ret)
|
goto error; /* This can be -ENOMEM */
|
}
|
|
ret = traceprobe_set_print_fmt(&tk->tp, is_return);
|
if (ret < 0)
|
goto error;
|
|
ret = register_trace_kprobe(tk);
|
if (ret) {
|
trace_probe_log_set_index(1);
|
if (ret == -EILSEQ)
|
trace_probe_log_err(0, BAD_INSN_BNDRY);
|
else if (ret == -ENOENT)
|
trace_probe_log_err(0, BAD_PROBE_ADDR);
|
else if (ret != -ENOMEM && ret != -EEXIST)
|
trace_probe_log_err(0, FAIL_REG_PROBE);
|
goto error;
|
}
|
|
out:
|
trace_probe_log_clear();
|
kfree(symbol);
|
return ret;
|
|
parse_error:
|
ret = -EINVAL;
|
error:
|
free_trace_kprobe(tk);
|
goto out;
|
}
|
|
static int create_or_delete_trace_kprobe(int argc, char **argv)
|
{
|
int ret;
|
|
if (argv[0][0] == '-')
|
return dyn_event_release(argc, argv, &trace_kprobe_ops);
|
|
ret = trace_kprobe_create(argc, (const char **)argv);
|
return ret == -ECANCELED ? -EINVAL : ret;
|
}
|
|
static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
|
{
|
return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
|
}
|
|
/**
|
* kprobe_event_cmd_init - Initialize a kprobe event command object
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
* @buf: A pointer to the buffer used to build the command
|
* @maxlen: The length of the buffer passed in @buf
|
*
|
* Initialize a synthetic event command object. Use this before
|
* calling any of the other kprobe_event functions.
|
*/
|
void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
|
{
|
dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
|
trace_kprobe_run_command);
|
}
|
EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
|
|
/**
|
* __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
* @name: The name of the kprobe event
|
* @loc: The location of the kprobe event
|
* @kretprobe: Is this a return probe?
|
* @args: Variable number of arg (pairs), one pair for each field
|
*
|
* NOTE: Users normally won't want to call this function directly, but
|
* rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
|
* adds a NULL to the end of the arg list. If this function is used
|
* directly, make sure the last arg in the variable arg list is NULL.
|
*
|
* Generate a kprobe event command to be executed by
|
* kprobe_event_gen_cmd_end(). This function can be used to generate the
|
* complete command or only the first part of it; in the latter case,
|
* kprobe_event_add_fields() can be used to add more fields following this.
|
*
|
* Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
|
* returns -EINVAL if @loc == NULL.
|
*
|
* Return: 0 if successful, error otherwise.
|
*/
|
int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
|
const char *name, const char *loc, ...)
|
{
|
char buf[MAX_EVENT_NAME_LEN];
|
struct dynevent_arg arg;
|
va_list args;
|
int ret;
|
|
if (cmd->type != DYNEVENT_TYPE_KPROBE)
|
return -EINVAL;
|
|
if (!loc)
|
return -EINVAL;
|
|
if (kretprobe)
|
snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
|
else
|
snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
|
|
ret = dynevent_str_add(cmd, buf);
|
if (ret)
|
return ret;
|
|
dynevent_arg_init(&arg, 0);
|
arg.str = loc;
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
if (ret)
|
return ret;
|
|
va_start(args, loc);
|
for (;;) {
|
const char *field;
|
|
field = va_arg(args, const char *);
|
if (!field)
|
break;
|
|
if (++cmd->n_fields > MAX_TRACE_ARGS) {
|
ret = -EINVAL;
|
break;
|
}
|
|
arg.str = field;
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
if (ret)
|
break;
|
}
|
va_end(args);
|
|
return ret;
|
}
|
EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
|
|
/**
|
* __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
* @args: Variable number of arg (pairs), one pair for each field
|
*
|
* NOTE: Users normally won't want to call this function directly, but
|
* rather use the kprobe_event_add_fields() wrapper, which
|
* automatically adds a NULL to the end of the arg list. If this
|
* function is used directly, make sure the last arg in the variable
|
* arg list is NULL.
|
*
|
* Add probe fields to an existing kprobe command using a variable
|
* list of args. Fields are added in the same order they're listed.
|
*
|
* Return: 0 if successful, error otherwise.
|
*/
|
int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
|
{
|
struct dynevent_arg arg;
|
va_list args;
|
int ret = 0;
|
|
if (cmd->type != DYNEVENT_TYPE_KPROBE)
|
return -EINVAL;
|
|
dynevent_arg_init(&arg, 0);
|
|
va_start(args, cmd);
|
for (;;) {
|
const char *field;
|
|
field = va_arg(args, const char *);
|
if (!field)
|
break;
|
|
if (++cmd->n_fields > MAX_TRACE_ARGS) {
|
ret = -EINVAL;
|
break;
|
}
|
|
arg.str = field;
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
if (ret)
|
break;
|
}
|
va_end(args);
|
|
return ret;
|
}
|
EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
|
|
/**
|
* kprobe_event_delete - Delete a kprobe event
|
* @name: The name of the kprobe event to delete
|
*
|
* Delete a kprobe event with the give @name from kernel code rather
|
* than directly from the command line.
|
*
|
* Return: 0 if successful, error otherwise.
|
*/
|
int kprobe_event_delete(const char *name)
|
{
|
char buf[MAX_EVENT_NAME_LEN];
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
|
|
return trace_run_command(buf, create_or_delete_trace_kprobe);
|
}
|
EXPORT_SYMBOL_GPL(kprobe_event_delete);
|
|
static int trace_kprobe_release(struct dyn_event *ev)
|
{
|
struct trace_kprobe *tk = to_trace_kprobe(ev);
|
int ret = unregister_trace_kprobe(tk);
|
|
if (!ret)
|
free_trace_kprobe(tk);
|
return ret;
|
}
|
|
static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
|
{
|
struct trace_kprobe *tk = to_trace_kprobe(ev);
|
int i;
|
|
seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
|
if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
|
seq_printf(m, "%d", tk->rp.maxactive);
|
seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
|
trace_probe_name(&tk->tp));
|
|
if (!tk->symbol)
|
seq_printf(m, " 0x%p", tk->rp.kp.addr);
|
else if (tk->rp.kp.offset)
|
seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
|
tk->rp.kp.offset);
|
else
|
seq_printf(m, " %s", trace_kprobe_symbol(tk));
|
|
for (i = 0; i < tk->tp.nr_args; i++)
|
seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
|
seq_putc(m, '\n');
|
|
return 0;
|
}
|
|
static int probes_seq_show(struct seq_file *m, void *v)
|
{
|
struct dyn_event *ev = v;
|
|
if (!is_trace_kprobe(ev))
|
return 0;
|
|
return trace_kprobe_show(m, ev);
|
}
|
|
static const struct seq_operations probes_seq_op = {
|
.start = dyn_event_seq_start,
|
.next = dyn_event_seq_next,
|
.stop = dyn_event_seq_stop,
|
.show = probes_seq_show
|
};
|
|
static int probes_open(struct inode *inode, struct file *file)
|
{
|
int ret;
|
|
ret = security_locked_down(LOCKDOWN_TRACEFS);
|
if (ret)
|
return ret;
|
|
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
|
ret = dyn_events_release_all(&trace_kprobe_ops);
|
if (ret < 0)
|
return ret;
|
}
|
|
return seq_open(file, &probes_seq_op);
|
}
|
|
static ssize_t probes_write(struct file *file, const char __user *buffer,
|
size_t count, loff_t *ppos)
|
{
|
return trace_parse_run_command(file, buffer, count, ppos,
|
create_or_delete_trace_kprobe);
|
}
|
|
static const struct file_operations kprobe_events_ops = {
|
.owner = THIS_MODULE,
|
.open = probes_open,
|
.read = seq_read,
|
.llseek = seq_lseek,
|
.release = seq_release,
|
.write = probes_write,
|
};
|
|
/* Probes profiling interfaces */
|
static int probes_profile_seq_show(struct seq_file *m, void *v)
|
{
|
struct dyn_event *ev = v;
|
struct trace_kprobe *tk;
|
unsigned long nmissed;
|
|
if (!is_trace_kprobe(ev))
|
return 0;
|
|
tk = to_trace_kprobe(ev);
|
nmissed = trace_kprobe_is_return(tk) ?
|
tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
|
seq_printf(m, " %-44s %15lu %15lu\n",
|
trace_probe_name(&tk->tp),
|
trace_kprobe_nhit(tk),
|
nmissed);
|
|
return 0;
|
}
|
|
static const struct seq_operations profile_seq_op = {
|
.start = dyn_event_seq_start,
|
.next = dyn_event_seq_next,
|
.stop = dyn_event_seq_stop,
|
.show = probes_profile_seq_show
|
};
|
|
static int profile_open(struct inode *inode, struct file *file)
|
{
|
int ret;
|
|
ret = security_locked_down(LOCKDOWN_TRACEFS);
|
if (ret)
|
return ret;
|
|
return seq_open(file, &profile_seq_op);
|
}
|
|
static const struct file_operations kprobe_profile_ops = {
|
.owner = THIS_MODULE,
|
.open = profile_open,
|
.read = seq_read,
|
.llseek = seq_lseek,
|
.release = seq_release,
|
};
|
|
/* Kprobe specific fetch functions */
|
|
/* Return the length of string -- including null terminal byte */
|
static nokprobe_inline int
|
fetch_store_strlen_user(unsigned long addr)
|
{
|
const void __user *uaddr = (__force const void __user *)addr;
|
|
return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
|
}
|
|
/* Return the length of string -- including null terminal byte */
|
static nokprobe_inline int
|
fetch_store_strlen(unsigned long addr)
|
{
|
int ret, len = 0;
|
u8 c;
|
|
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
|
if (addr < TASK_SIZE)
|
return fetch_store_strlen_user(addr);
|
#endif
|
|
do {
|
ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
|
len++;
|
} while (c && ret == 0 && len < MAX_STRING_SIZE);
|
|
return (ret < 0) ? ret : len;
|
}
|
|
/*
|
* Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
|
* with max length and relative data location.
|
*/
|
static nokprobe_inline int
|
fetch_store_string_user(unsigned long addr, void *dest, void *base)
|
{
|
const void __user *uaddr = (__force const void __user *)addr;
|
int maxlen = get_loc_len(*(u32 *)dest);
|
void *__dest;
|
long ret;
|
|
if (unlikely(!maxlen))
|
return -ENOMEM;
|
|
__dest = get_loc_data(dest, base);
|
|
ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
|
if (ret >= 0)
|
*(u32 *)dest = make_data_loc(ret, __dest - base);
|
|
return ret;
|
}
|
|
/*
|
* Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
|
* length and relative data location.
|
*/
|
static nokprobe_inline int
|
fetch_store_string(unsigned long addr, void *dest, void *base)
|
{
|
int maxlen = get_loc_len(*(u32 *)dest);
|
void *__dest;
|
long ret;
|
|
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
|
if ((unsigned long)addr < TASK_SIZE)
|
return fetch_store_string_user(addr, dest, base);
|
#endif
|
|
if (unlikely(!maxlen))
|
return -ENOMEM;
|
|
__dest = get_loc_data(dest, base);
|
|
/*
|
* Try to get string again, since the string can be changed while
|
* probing.
|
*/
|
ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
|
if (ret >= 0)
|
*(u32 *)dest = make_data_loc(ret, __dest - base);
|
|
return ret;
|
}
|
|
static nokprobe_inline int
|
probe_mem_read_user(void *dest, void *src, size_t size)
|
{
|
const void __user *uaddr = (__force const void __user *)src;
|
|
return copy_from_user_nofault(dest, uaddr, size);
|
}
|
|
static nokprobe_inline int
|
probe_mem_read(void *dest, void *src, size_t size)
|
{
|
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
|
if ((unsigned long)src < TASK_SIZE)
|
return probe_mem_read_user(dest, src, size);
|
#endif
|
return copy_from_kernel_nofault(dest, src, size);
|
}
|
|
/* Note that we don't verify it, since the code does not come from user space */
|
static int
|
process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
|
void *base)
|
{
|
unsigned long val;
|
|
retry:
|
/* 1st stage: get value from context */
|
switch (code->op) {
|
case FETCH_OP_REG:
|
val = regs_get_register(regs, code->param);
|
break;
|
case FETCH_OP_STACK:
|
val = regs_get_kernel_stack_nth(regs, code->param);
|
break;
|
case FETCH_OP_STACKP:
|
val = kernel_stack_pointer(regs);
|
break;
|
case FETCH_OP_RETVAL:
|
val = regs_return_value(regs);
|
break;
|
case FETCH_OP_IMM:
|
val = code->immediate;
|
break;
|
case FETCH_OP_COMM:
|
val = (unsigned long)current->comm;
|
break;
|
case FETCH_OP_DATA:
|
val = (unsigned long)code->data;
|
break;
|
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
|
case FETCH_OP_ARG:
|
val = regs_get_kernel_argument(regs, code->param);
|
break;
|
#endif
|
case FETCH_NOP_SYMBOL: /* Ignore a place holder */
|
code++;
|
goto retry;
|
default:
|
return -EILSEQ;
|
}
|
code++;
|
|
return process_fetch_insn_bottom(code, val, dest, base);
|
}
|
NOKPROBE_SYMBOL(process_fetch_insn)
|
|
/* Kprobe handler */
|
static nokprobe_inline void
|
__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
|
struct trace_event_file *trace_file)
|
{
|
struct kprobe_trace_entry_head *entry;
|
struct trace_event_call *call = trace_probe_event_call(&tk->tp);
|
struct trace_event_buffer fbuffer;
|
int dsize;
|
|
WARN_ON(call != trace_file->event_call);
|
|
if (trace_trigger_soft_disabled(trace_file))
|
return;
|
|
fbuffer.trace_ctx = tracing_gen_ctx();
|
fbuffer.trace_file = trace_file;
|
|
dsize = __get_data_size(&tk->tp, regs);
|
|
fbuffer.event =
|
trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
|
call->event.type,
|
sizeof(*entry) + tk->tp.size + dsize,
|
fbuffer.trace_ctx);
|
if (!fbuffer.event)
|
return;
|
|
fbuffer.regs = regs;
|
entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
|
entry->ip = (unsigned long)tk->rp.kp.addr;
|
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
|
|
trace_event_buffer_commit(&fbuffer);
|
}
|
|
static void
|
kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
|
{
|
struct event_file_link *link;
|
|
trace_probe_for_each_link_rcu(link, &tk->tp)
|
__kprobe_trace_func(tk, regs, link->file);
|
}
|
NOKPROBE_SYMBOL(kprobe_trace_func);
|
|
/* Kretprobe handler */
|
static nokprobe_inline void
|
__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
struct pt_regs *regs,
|
struct trace_event_file *trace_file)
|
{
|
struct kretprobe_trace_entry_head *entry;
|
struct trace_event_buffer fbuffer;
|
struct trace_event_call *call = trace_probe_event_call(&tk->tp);
|
int dsize;
|
|
WARN_ON(call != trace_file->event_call);
|
|
if (trace_trigger_soft_disabled(trace_file))
|
return;
|
|
fbuffer.trace_ctx = tracing_gen_ctx();
|
fbuffer.trace_file = trace_file;
|
|
dsize = __get_data_size(&tk->tp, regs);
|
fbuffer.event =
|
trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
|
call->event.type,
|
sizeof(*entry) + tk->tp.size + dsize,
|
fbuffer.trace_ctx);
|
if (!fbuffer.event)
|
return;
|
|
fbuffer.regs = regs;
|
entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
|
entry->func = (unsigned long)tk->rp.kp.addr;
|
entry->ret_ip = (unsigned long)ri->ret_addr;
|
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
|
|
trace_event_buffer_commit(&fbuffer);
|
}
|
|
static void
|
kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
struct pt_regs *regs)
|
{
|
struct event_file_link *link;
|
|
trace_probe_for_each_link_rcu(link, &tk->tp)
|
__kretprobe_trace_func(tk, ri, regs, link->file);
|
}
|
NOKPROBE_SYMBOL(kretprobe_trace_func);
|
|
/* Event entry printers */
|
static enum print_line_t
|
print_kprobe_event(struct trace_iterator *iter, int flags,
|
struct trace_event *event)
|
{
|
struct kprobe_trace_entry_head *field;
|
struct trace_seq *s = &iter->seq;
|
struct trace_probe *tp;
|
|
field = (struct kprobe_trace_entry_head *)iter->ent;
|
tp = trace_probe_primary_from_call(
|
container_of(event, struct trace_event_call, event));
|
if (WARN_ON_ONCE(!tp))
|
goto out;
|
|
trace_seq_printf(s, "%s: (", trace_probe_name(tp));
|
|
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
|
goto out;
|
|
trace_seq_putc(s, ')');
|
|
if (print_probe_args(s, tp->args, tp->nr_args,
|
(u8 *)&field[1], field) < 0)
|
goto out;
|
|
trace_seq_putc(s, '\n');
|
out:
|
return trace_handle_return(s);
|
}
|
|
static enum print_line_t
|
print_kretprobe_event(struct trace_iterator *iter, int flags,
|
struct trace_event *event)
|
{
|
struct kretprobe_trace_entry_head *field;
|
struct trace_seq *s = &iter->seq;
|
struct trace_probe *tp;
|
|
field = (struct kretprobe_trace_entry_head *)iter->ent;
|
tp = trace_probe_primary_from_call(
|
container_of(event, struct trace_event_call, event));
|
if (WARN_ON_ONCE(!tp))
|
goto out;
|
|
trace_seq_printf(s, "%s: (", trace_probe_name(tp));
|
|
if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
|
goto out;
|
|
trace_seq_puts(s, " <- ");
|
|
if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
|
goto out;
|
|
trace_seq_putc(s, ')');
|
|
if (print_probe_args(s, tp->args, tp->nr_args,
|
(u8 *)&field[1], field) < 0)
|
goto out;
|
|
trace_seq_putc(s, '\n');
|
|
out:
|
return trace_handle_return(s);
|
}
|
|
|
static int kprobe_event_define_fields(struct trace_event_call *event_call)
|
{
|
int ret;
|
struct kprobe_trace_entry_head field;
|
struct trace_probe *tp;
|
|
tp = trace_probe_primary_from_call(event_call);
|
if (WARN_ON_ONCE(!tp))
|
return -ENOENT;
|
|
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
|
|
return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
|
}
|
|
static int kretprobe_event_define_fields(struct trace_event_call *event_call)
|
{
|
int ret;
|
struct kretprobe_trace_entry_head field;
|
struct trace_probe *tp;
|
|
tp = trace_probe_primary_from_call(event_call);
|
if (WARN_ON_ONCE(!tp))
|
return -ENOENT;
|
|
DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
|
DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
|
|
return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
|
}
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
/* Kprobe profile handler */
|
static int
|
kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
|
{
|
struct trace_event_call *call = trace_probe_event_call(&tk->tp);
|
struct kprobe_trace_entry_head *entry;
|
struct hlist_head *head;
|
int size, __size, dsize;
|
int rctx;
|
|
if (bpf_prog_array_valid(call)) {
|
unsigned long orig_ip = instruction_pointer(regs);
|
int ret;
|
|
ret = trace_call_bpf(call, regs);
|
|
/*
|
* We need to check and see if we modified the pc of the
|
* pt_regs, and if so return 1 so that we don't do the
|
* single stepping.
|
*/
|
if (orig_ip != instruction_pointer(regs))
|
return 1;
|
if (!ret)
|
return 0;
|
}
|
|
head = this_cpu_ptr(call->perf_events);
|
if (hlist_empty(head))
|
return 0;
|
|
dsize = __get_data_size(&tk->tp, regs);
|
__size = sizeof(*entry) + tk->tp.size + dsize;
|
size = ALIGN(__size + sizeof(u32), sizeof(u64));
|
size -= sizeof(u32);
|
|
entry = perf_trace_buf_alloc(size, NULL, &rctx);
|
if (!entry)
|
return 0;
|
|
entry->ip = (unsigned long)tk->rp.kp.addr;
|
memset(&entry[1], 0, dsize);
|
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
|
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
|
head, NULL);
|
return 0;
|
}
|
NOKPROBE_SYMBOL(kprobe_perf_func);
|
|
/* Kretprobe profile handler */
|
static void
|
kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
struct pt_regs *regs)
|
{
|
struct trace_event_call *call = trace_probe_event_call(&tk->tp);
|
struct kretprobe_trace_entry_head *entry;
|
struct hlist_head *head;
|
int size, __size, dsize;
|
int rctx;
|
|
if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
|
return;
|
|
head = this_cpu_ptr(call->perf_events);
|
if (hlist_empty(head))
|
return;
|
|
dsize = __get_data_size(&tk->tp, regs);
|
__size = sizeof(*entry) + tk->tp.size + dsize;
|
size = ALIGN(__size + sizeof(u32), sizeof(u64));
|
size -= sizeof(u32);
|
|
entry = perf_trace_buf_alloc(size, NULL, &rctx);
|
if (!entry)
|
return;
|
|
entry->func = (unsigned long)tk->rp.kp.addr;
|
entry->ret_ip = (unsigned long)ri->ret_addr;
|
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
|
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
|
head, NULL);
|
}
|
NOKPROBE_SYMBOL(kretprobe_perf_func);
|
|
int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
|
const char **symbol, u64 *probe_offset,
|
u64 *probe_addr, bool perf_type_tracepoint)
|
{
|
const char *pevent = trace_event_name(event->tp_event);
|
const char *group = event->tp_event->class->system;
|
struct trace_kprobe *tk;
|
|
if (perf_type_tracepoint)
|
tk = find_trace_kprobe(pevent, group);
|
else
|
tk = trace_kprobe_primary_from_call(event->tp_event);
|
if (!tk)
|
return -EINVAL;
|
|
*fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
|
: BPF_FD_TYPE_KPROBE;
|
if (tk->symbol) {
|
*symbol = tk->symbol;
|
*probe_offset = tk->rp.kp.offset;
|
*probe_addr = 0;
|
} else {
|
*symbol = NULL;
|
*probe_offset = 0;
|
*probe_addr = (unsigned long)tk->rp.kp.addr;
|
}
|
return 0;
|
}
|
#endif /* CONFIG_PERF_EVENTS */
|
|
/*
|
* called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
|
*
|
* kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
|
* lockless, but we can't race with this __init function.
|
*/
|
static int kprobe_register(struct trace_event_call *event,
|
enum trace_reg type, void *data)
|
{
|
struct trace_event_file *file = data;
|
|
switch (type) {
|
case TRACE_REG_REGISTER:
|
return enable_trace_kprobe(event, file);
|
case TRACE_REG_UNREGISTER:
|
return disable_trace_kprobe(event, file);
|
|
#ifdef CONFIG_PERF_EVENTS
|
case TRACE_REG_PERF_REGISTER:
|
return enable_trace_kprobe(event, NULL);
|
case TRACE_REG_PERF_UNREGISTER:
|
return disable_trace_kprobe(event, NULL);
|
case TRACE_REG_PERF_OPEN:
|
case TRACE_REG_PERF_CLOSE:
|
case TRACE_REG_PERF_ADD:
|
case TRACE_REG_PERF_DEL:
|
return 0;
|
#endif
|
}
|
return 0;
|
}
|
|
static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
|
{
|
struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
|
int ret = 0;
|
|
raw_cpu_inc(*tk->nhit);
|
|
if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
|
kprobe_trace_func(tk, regs);
|
#ifdef CONFIG_PERF_EVENTS
|
if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
|
ret = kprobe_perf_func(tk, regs);
|
#endif
|
return ret;
|
}
|
NOKPROBE_SYMBOL(kprobe_dispatcher);
|
|
static int
|
kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
|
{
|
struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
|
|
raw_cpu_inc(*tk->nhit);
|
|
if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
|
kretprobe_trace_func(tk, ri, regs);
|
#ifdef CONFIG_PERF_EVENTS
|
if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
|
kretprobe_perf_func(tk, ri, regs);
|
#endif
|
return 0; /* We don't tweek kernel, so just return 0 */
|
}
|
NOKPROBE_SYMBOL(kretprobe_dispatcher);
|
|
static struct trace_event_functions kretprobe_funcs = {
|
.trace = print_kretprobe_event
|
};
|
|
static struct trace_event_functions kprobe_funcs = {
|
.trace = print_kprobe_event
|
};
|
|
static struct trace_event_fields kretprobe_fields_array[] = {
|
{ .type = TRACE_FUNCTION_TYPE,
|
.define_fields = kretprobe_event_define_fields },
|
{}
|
};
|
|
static struct trace_event_fields kprobe_fields_array[] = {
|
{ .type = TRACE_FUNCTION_TYPE,
|
.define_fields = kprobe_event_define_fields },
|
{}
|
};
|
|
static inline void init_trace_event_call(struct trace_kprobe *tk)
|
{
|
struct trace_event_call *call = trace_probe_event_call(&tk->tp);
|
|
if (trace_kprobe_is_return(tk)) {
|
call->event.funcs = &kretprobe_funcs;
|
call->class->fields_array = kretprobe_fields_array;
|
} else {
|
call->event.funcs = &kprobe_funcs;
|
call->class->fields_array = kprobe_fields_array;
|
}
|
|
call->flags = TRACE_EVENT_FL_KPROBE;
|
call->class->reg = kprobe_register;
|
}
|
|
static int register_kprobe_event(struct trace_kprobe *tk)
|
{
|
init_trace_event_call(tk);
|
|
return trace_probe_register_event_call(&tk->tp);
|
}
|
|
static int unregister_kprobe_event(struct trace_kprobe *tk)
|
{
|
return trace_probe_unregister_event_call(&tk->tp);
|
}
|
|
#ifdef CONFIG_PERF_EVENTS
|
/* create a trace_kprobe, but don't add it to global lists */
|
struct trace_event_call *
|
create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
|
bool is_return)
|
{
|
struct trace_kprobe *tk;
|
int ret;
|
char *event;
|
|
/*
|
* local trace_kprobes are not added to dyn_event, so they are never
|
* searched in find_trace_kprobe(). Therefore, there is no concern of
|
* duplicated name here.
|
*/
|
event = func ? func : "DUMMY_EVENT";
|
|
tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
|
offs, 0 /* maxactive */, 0 /* nargs */,
|
is_return);
|
|
if (IS_ERR(tk)) {
|
pr_info("Failed to allocate trace_probe.(%d)\n",
|
(int)PTR_ERR(tk));
|
return ERR_CAST(tk);
|
}
|
|
init_trace_event_call(tk);
|
|
if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
|
ret = -ENOMEM;
|
goto error;
|
}
|
|
ret = __register_trace_kprobe(tk);
|
if (ret < 0)
|
goto error;
|
|
return trace_probe_event_call(&tk->tp);
|
error:
|
free_trace_kprobe(tk);
|
return ERR_PTR(ret);
|
}
|
|
void destroy_local_trace_kprobe(struct trace_event_call *event_call)
|
{
|
struct trace_kprobe *tk;
|
|
tk = trace_kprobe_primary_from_call(event_call);
|
if (unlikely(!tk))
|
return;
|
|
if (trace_probe_is_enabled(&tk->tp)) {
|
WARN_ON(1);
|
return;
|
}
|
|
__unregister_trace_kprobe(tk);
|
|
free_trace_kprobe(tk);
|
}
|
#endif /* CONFIG_PERF_EVENTS */
|
|
static __init void enable_boot_kprobe_events(void)
|
{
|
struct trace_array *tr = top_trace_array();
|
struct trace_event_file *file;
|
struct trace_kprobe *tk;
|
struct dyn_event *pos;
|
|
mutex_lock(&event_mutex);
|
for_each_trace_kprobe(tk, pos) {
|
list_for_each_entry(file, &tr->events, list)
|
if (file->event_call == trace_probe_event_call(&tk->tp))
|
trace_event_enable_disable(file, 1, 0);
|
}
|
mutex_unlock(&event_mutex);
|
}
|
|
static __init void setup_boot_kprobe_events(void)
|
{
|
char *p, *cmd = kprobe_boot_events_buf;
|
int ret;
|
|
strreplace(kprobe_boot_events_buf, ',', ' ');
|
|
while (cmd && *cmd != '\0') {
|
p = strchr(cmd, ';');
|
if (p)
|
*p++ = '\0';
|
|
ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
|
if (ret)
|
pr_warn("Failed to add event(%d): %s\n", ret, cmd);
|
|
cmd = p;
|
}
|
|
enable_boot_kprobe_events();
|
}
|
|
/*
|
* Register dynevent at core_initcall. This allows kernel to setup kprobe
|
* events in postcore_initcall without tracefs.
|
*/
|
static __init int init_kprobe_trace_early(void)
|
{
|
int ret;
|
|
ret = dyn_event_register(&trace_kprobe_ops);
|
if (ret)
|
return ret;
|
|
if (register_module_notifier(&trace_kprobe_module_nb))
|
return -EINVAL;
|
|
return 0;
|
}
|
core_initcall(init_kprobe_trace_early);
|
|
/* Make a tracefs interface for controlling probe points */
|
static __init int init_kprobe_trace(void)
|
{
|
int ret;
|
struct dentry *entry;
|
|
ret = tracing_init_dentry();
|
if (ret)
|
return 0;
|
|
entry = tracefs_create_file("kprobe_events", 0644, NULL,
|
NULL, &kprobe_events_ops);
|
|
/* Event list interface */
|
if (!entry)
|
pr_warn("Could not create tracefs 'kprobe_events' entry\n");
|
|
/* Profile interface */
|
entry = tracefs_create_file("kprobe_profile", 0444, NULL,
|
NULL, &kprobe_profile_ops);
|
|
if (!entry)
|
pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
|
|
setup_boot_kprobe_events();
|
|
return 0;
|
}
|
fs_initcall(init_kprobe_trace);
|
|
|
#ifdef CONFIG_FTRACE_STARTUP_TEST
|
static __init struct trace_event_file *
|
find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
|
{
|
struct trace_event_file *file;
|
|
list_for_each_entry(file, &tr->events, list)
|
if (file->event_call == trace_probe_event_call(&tk->tp))
|
return file;
|
|
return NULL;
|
}
|
|
/*
|
* Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
|
* stage, we can do this lockless.
|
*/
|
static __init int kprobe_trace_self_tests_init(void)
|
{
|
int ret, warn = 0;
|
int (*target)(int, int, int, int, int, int);
|
struct trace_kprobe *tk;
|
struct trace_event_file *file;
|
|
if (tracing_is_disabled())
|
return -ENODEV;
|
|
if (tracing_selftest_disabled)
|
return 0;
|
|
target = kprobe_trace_selftest_target;
|
|
pr_info("Testing kprobe tracing: ");
|
|
ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
|
create_or_delete_trace_kprobe);
|
if (WARN_ON_ONCE(ret)) {
|
pr_warn("error on probing function entry.\n");
|
warn++;
|
} else {
|
/* Enable trace point */
|
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
|
if (WARN_ON_ONCE(tk == NULL)) {
|
pr_warn("error on getting new probe.\n");
|
warn++;
|
} else {
|
file = find_trace_probe_file(tk, top_trace_array());
|
if (WARN_ON_ONCE(file == NULL)) {
|
pr_warn("error on getting probe file.\n");
|
warn++;
|
} else
|
enable_trace_kprobe(
|
trace_probe_event_call(&tk->tp), file);
|
}
|
}
|
|
ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
|
create_or_delete_trace_kprobe);
|
if (WARN_ON_ONCE(ret)) {
|
pr_warn("error on probing function return.\n");
|
warn++;
|
} else {
|
/* Enable trace point */
|
tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
|
if (WARN_ON_ONCE(tk == NULL)) {
|
pr_warn("error on getting 2nd new probe.\n");
|
warn++;
|
} else {
|
file = find_trace_probe_file(tk, top_trace_array());
|
if (WARN_ON_ONCE(file == NULL)) {
|
pr_warn("error on getting probe file.\n");
|
warn++;
|
} else
|
enable_trace_kprobe(
|
trace_probe_event_call(&tk->tp), file);
|
}
|
}
|
|
if (warn)
|
goto end;
|
|
ret = target(1, 2, 3, 4, 5, 6);
|
|
/*
|
* Not expecting an error here, the check is only to prevent the
|
* optimizer from removing the call to target() as otherwise there
|
* are no side-effects and the call is never performed.
|
*/
|
if (ret != 21)
|
warn++;
|
|
/* Disable trace points before removing it */
|
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
|
if (WARN_ON_ONCE(tk == NULL)) {
|
pr_warn("error on getting test probe.\n");
|
warn++;
|
} else {
|
if (trace_kprobe_nhit(tk) != 1) {
|
pr_warn("incorrect number of testprobe hits\n");
|
warn++;
|
}
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
if (WARN_ON_ONCE(file == NULL)) {
|
pr_warn("error on getting probe file.\n");
|
warn++;
|
} else
|
disable_trace_kprobe(
|
trace_probe_event_call(&tk->tp), file);
|
}
|
|
tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
|
if (WARN_ON_ONCE(tk == NULL)) {
|
pr_warn("error on getting 2nd test probe.\n");
|
warn++;
|
} else {
|
if (trace_kprobe_nhit(tk) != 1) {
|
pr_warn("incorrect number of testprobe2 hits\n");
|
warn++;
|
}
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
if (WARN_ON_ONCE(file == NULL)) {
|
pr_warn("error on getting probe file.\n");
|
warn++;
|
} else
|
disable_trace_kprobe(
|
trace_probe_event_call(&tk->tp), file);
|
}
|
|
ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
|
if (WARN_ON_ONCE(ret)) {
|
pr_warn("error on deleting a probe.\n");
|
warn++;
|
}
|
|
ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
|
if (WARN_ON_ONCE(ret)) {
|
pr_warn("error on deleting a probe.\n");
|
warn++;
|
}
|
|
end:
|
ret = dyn_events_release_all(&trace_kprobe_ops);
|
if (WARN_ON_ONCE(ret)) {
|
pr_warn("error on cleaning up probes.\n");
|
warn++;
|
}
|
/*
|
* Wait for the optimizer work to finish. Otherwise it might fiddle
|
* with probes in already freed __init text.
|
*/
|
wait_for_kprobe_optimizer();
|
if (warn)
|
pr_cont("NG: Some tests are failed. Please check them.\n");
|
else
|
pr_cont("OK\n");
|
return 0;
|
}
|
|
late_initcall(kprobe_trace_self_tests_init);
|
|
#endif
|
