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Merge tag 'probes-v6.12' of git://git.kernel.org/pub/scm/linux/kernel…
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…/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - uprobes: make trace_uprobe->nhit counter a per-CPU one

   This makes uprobe event's hit counter per-CPU for improving
   scalability on multi-core environment

 - kprobes: Remove obsoleted declaration for init_test_probes

   Remove unused init_test_probes() from header

 - Raw tracepoint probe supports raw tracepoint events on modules:
     - add a function for iterating over all tracepoints in all modules
     - add a function for iterating over tracepoints in a module
     - support raw tracepoint events on modules
     - support raw tracepoints on future loaded modules
     - add a test for tracepoint events on modules"

* tag 'probes-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  sefltests/tracing: Add a test for tracepoint events on modules
  tracing/fprobe: Support raw tracepoints on future loaded modules
  tracing/fprobe: Support raw tracepoint events on modules
  tracepoint: Support iterating tracepoints in a loading module
  tracepoint: Support iterating over tracepoints on modules
  kprobes: Remove obsoleted declaration for init_test_probes
  uprobes: turn trace_uprobe's nhit counter to be per-CPU one
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@torvalds
torvalds committed Sep 26, 2024
2 parents 0181f8c + 4e78dd6 commit 5159938
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Showing 8 changed files with 275 additions and 62 deletions.
9 changes: 0 additions & 9 deletions include/linux/kprobes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -269,15 +269,6 @@ extern unsigned long __stop_kprobe_blacklist[];

extern struct kretprobe_blackpoint kretprobe_blacklist[];

#ifdef CONFIG_KPROBES_SANITY_TEST
extern int init_test_probes(void);
#else /* !CONFIG_KPROBES_SANITY_TEST */
static inline int init_test_probes(void)
{
return 0;
}
#endif /* CONFIG_KPROBES_SANITY_TEST */

extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
Expand Down
20 changes: 20 additions & 0 deletions include/linux/tracepoint.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,13 @@ struct tp_module {
bool trace_module_has_bad_taint(struct module *mod);
extern int register_tracepoint_module_notifier(struct notifier_block *nb);
extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
struct module *, void *),
void *priv);
void for_each_tracepoint_in_module(struct module *,
void (*fct)(struct tracepoint *,
struct module *, void *),
void *priv);
#else
static inline bool trace_module_has_bad_taint(struct module *mod)
{
Expand All @@ -79,6 +86,19 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
{
return 0;
}
static inline
void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
struct module *, void *),
void *priv)
{
}
static inline
void for_each_tracepoint_in_module(struct module *mod,
void (*fct)(struct tracepoint *,
struct module *, void *),
void *priv)
{
}
#endif /* CONFIG_MODULES */

/*
Expand Down
179 changes: 130 additions & 49 deletions kernel/trace/trace_fprobe.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#define FPROBE_EVENT_SYSTEM "fprobes"
#define TRACEPOINT_EVENT_SYSTEM "tracepoints"
#define RETHOOK_MAXACTIVE_MAX 4096
#define TRACEPOINT_STUB ERR_PTR(-ENOENT)

static int trace_fprobe_create(const char *raw_command);
static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev);
Expand Down Expand Up @@ -385,6 +386,7 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group,
const char *event,
const char *symbol,
struct tracepoint *tpoint,
struct module *mod,
int maxactive,
int nargs, bool is_return)
{
Expand All @@ -405,6 +407,7 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group,
tf->fp.entry_handler = fentry_dispatcher;

tf->tpoint = tpoint;
tf->mod = mod;
tf->fp.nr_maxactive = maxactive;

ret = trace_probe_init(&tf->tp, event, group, false, nargs);
Expand Down Expand Up @@ -672,6 +675,24 @@ static int unregister_fprobe_event(struct trace_fprobe *tf)
return trace_probe_unregister_event_call(&tf->tp);
}

static int __regsiter_tracepoint_fprobe(struct trace_fprobe *tf)
{
struct tracepoint *tpoint = tf->tpoint;
unsigned long ip = (unsigned long)tpoint->probestub;
int ret;

/*
* Here, we do 2 steps to enable fprobe on a tracepoint.
* At first, put __probestub_##TP function on the tracepoint
* and put a fprobe on the stub function.
*/
ret = tracepoint_probe_register_prio_may_exist(tpoint,
tpoint->probestub, NULL, 0);
if (ret < 0)
return ret;
return register_fprobe_ips(&tf->fp, &ip, 1);
}

/* Internal register function - just handle fprobe and flags */
static int __register_trace_fprobe(struct trace_fprobe *tf)
{
Expand All @@ -698,18 +719,12 @@ static int __register_trace_fprobe(struct trace_fprobe *tf)
tf->fp.flags |= FPROBE_FL_DISABLED;

if (trace_fprobe_is_tracepoint(tf)) {
struct tracepoint *tpoint = tf->tpoint;
unsigned long ip = (unsigned long)tpoint->probestub;
/*
* Here, we do 2 steps to enable fprobe on a tracepoint.
* At first, put __probestub_##TP function on the tracepoint
* and put a fprobe on the stub function.
*/
ret = tracepoint_probe_register_prio_may_exist(tpoint,
tpoint->probestub, NULL, 0);
if (ret < 0)
return ret;
return register_fprobe_ips(&tf->fp, &ip, 1);

/* This tracepoint is not loaded yet */
if (tf->tpoint == TRACEPOINT_STUB)
return 0;

return __regsiter_tracepoint_fprobe(tf);
}

/* TODO: handle filter, nofilter or symbol list */
Expand Down Expand Up @@ -862,20 +877,106 @@ static int register_trace_fprobe(struct trace_fprobe *tf)
return ret;
}

struct __find_tracepoint_cb_data {
const char *tp_name;
struct tracepoint *tpoint;
struct module *mod;
};

static void __find_tracepoint_module_cb(struct tracepoint *tp, struct module *mod, void *priv)
{
struct __find_tracepoint_cb_data *data = priv;

if (!data->tpoint && !strcmp(data->tp_name, tp->name)) {
data->tpoint = tp;
if (!data->mod) {
data->mod = mod;
if (!try_module_get(data->mod)) {
data->tpoint = NULL;
data->mod = NULL;
}
}
}
}

static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
{
struct __find_tracepoint_cb_data *data = priv;

if (!data->tpoint && !strcmp(data->tp_name, tp->name))
data->tpoint = tp;
}

/*
* Find a tracepoint from kernel and module. If the tracepoint is in a module,
* this increments the module refcount to prevent unloading until the
* trace_fprobe is registered to the list. After registering the trace_fprobe
* on the trace_fprobe list, the module refcount is decremented because
* tracepoint_probe_module_cb will handle it.
*/
static struct tracepoint *find_tracepoint(const char *tp_name,
struct module **tp_mod)
{
struct __find_tracepoint_cb_data data = {
.tp_name = tp_name,
.mod = NULL,
};

for_each_kernel_tracepoint(__find_tracepoint_cb, &data);

if (!data.tpoint && IS_ENABLED(CONFIG_MODULES)) {
for_each_module_tracepoint(__find_tracepoint_module_cb, &data);
*tp_mod = data.mod;
}

return data.tpoint;
}

#ifdef CONFIG_MODULES
static void reenable_trace_fprobe(struct trace_fprobe *tf)
{
struct trace_probe *tp = &tf->tp;

list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
__enable_trace_fprobe(tf);
}
}

static struct tracepoint *find_tracepoint_in_module(struct module *mod,
const char *tp_name)
{
struct __find_tracepoint_cb_data data = {
.tp_name = tp_name,
.mod = mod,
};

for_each_tracepoint_in_module(mod, __find_tracepoint_module_cb, &data);
return data.tpoint;
}

static int __tracepoint_probe_module_cb(struct notifier_block *self,
unsigned long val, void *data)
{
struct tp_module *tp_mod = data;
struct tracepoint *tpoint;
struct trace_fprobe *tf;
struct dyn_event *pos;

if (val != MODULE_STATE_GOING)
if (val != MODULE_STATE_GOING && val != MODULE_STATE_COMING)
return NOTIFY_DONE;

mutex_lock(&event_mutex);
for_each_trace_fprobe(tf, pos) {
if (tp_mod->mod == tf->mod) {
if (val == MODULE_STATE_COMING && tf->tpoint == TRACEPOINT_STUB) {
tpoint = find_tracepoint_in_module(tp_mod->mod, tf->symbol);
if (tpoint) {
tf->tpoint = tpoint;
tf->mod = tp_mod->mod;
if (!WARN_ON_ONCE(__regsiter_tracepoint_fprobe(tf)) &&
trace_probe_is_enabled(&tf->tp))
reenable_trace_fprobe(tf);
}
} else if (val == MODULE_STATE_GOING && tp_mod->mod == tf->mod) {
tracepoint_probe_unregister(tf->tpoint,
tf->tpoint->probestub, NULL);
tf->tpoint = NULL;
Expand All @@ -892,30 +993,6 @@ static struct notifier_block tracepoint_module_nb = {
};
#endif /* CONFIG_MODULES */

struct __find_tracepoint_cb_data {
const char *tp_name;
struct tracepoint *tpoint;
};

static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
{
struct __find_tracepoint_cb_data *data = priv;

if (!data->tpoint && !strcmp(data->tp_name, tp->name))
data->tpoint = tp;
}

static struct tracepoint *find_tracepoint(const char *tp_name)
{
struct __find_tracepoint_cb_data data = {
.tp_name = tp_name,
};

for_each_kernel_tracepoint(__find_tracepoint_cb, &data);

return data.tpoint;
}

static int parse_symbol_and_return(int argc, const char *argv[],
char **symbol, bool *is_return,
bool is_tracepoint)
Expand Down Expand Up @@ -996,6 +1073,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
char abuf[MAX_BTF_ARGS_LEN];
char *dbuf = NULL;
bool is_tracepoint = false;
struct module *tp_mod = NULL;
struct tracepoint *tpoint = NULL;
struct traceprobe_parse_context ctx = {
.flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE,
Expand Down Expand Up @@ -1080,15 +1158,20 @@ static int __trace_fprobe_create(int argc, const char *argv[])

if (is_tracepoint) {
ctx.flags |= TPARG_FL_TPOINT;
tpoint = find_tracepoint(symbol);
if (!tpoint) {
tpoint = find_tracepoint(symbol, &tp_mod);
if (tpoint) {
ctx.funcname = kallsyms_lookup(
(unsigned long)tpoint->probestub,
NULL, NULL, NULL, sbuf);
} else if (IS_ENABLED(CONFIG_MODULES)) {
/* This *may* be loaded afterwards */
tpoint = TRACEPOINT_STUB;
ctx.funcname = symbol;
} else {
trace_probe_log_set_index(1);
trace_probe_log_err(0, NO_TRACEPOINT);
goto parse_error;
}
ctx.funcname = kallsyms_lookup(
(unsigned long)tpoint->probestub,
NULL, NULL, NULL, sbuf);
} else
ctx.funcname = symbol;

Expand All @@ -1110,19 +1193,15 @@ static int __trace_fprobe_create(int argc, const char *argv[])
goto out;

/* setup a probe */
tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
argc, is_return);
tf = alloc_trace_fprobe(group, event, symbol, tpoint, tp_mod,
maxactive, argc, is_return);
if (IS_ERR(tf)) {
ret = PTR_ERR(tf);
/* This must return -ENOMEM, else there is a bug */
WARN_ON_ONCE(ret != -ENOMEM);
goto out; /* We know tf is not allocated */
}

if (is_tracepoint)
tf->mod = __module_text_address(
(unsigned long)tf->tpoint->probestub);

/* parse arguments */
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
trace_probe_log_set_index(i + 2);
Expand Down Expand Up @@ -1155,6 +1234,8 @@ static int __trace_fprobe_create(int argc, const char *argv[])
}

out:
if (tp_mod)
module_put(tp_mod);
traceprobe_finish_parse(&ctx);
trace_probe_log_clear();
kfree(new_argv);
Expand Down
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