mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Ingo Molnar](/assets/img/avatar_default.png)
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
566 lines
15 KiB
C
566 lines
15 KiB
C
/*
|
|
* Copyright (C) 2008-2014 Mathieu Desnoyers
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/types.h>
|
|
#include <linux/jhash.h>
|
|
#include <linux/list.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/tracepoint.h>
|
|
#include <linux/err.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/sched/task.h>
|
|
#include <linux/static_key.h>
|
|
|
|
extern struct tracepoint * const __start___tracepoints_ptrs[];
|
|
extern struct tracepoint * const __stop___tracepoints_ptrs[];
|
|
|
|
/* Set to 1 to enable tracepoint debug output */
|
|
static const int tracepoint_debug;
|
|
|
|
#ifdef CONFIG_MODULES
|
|
/*
|
|
* Tracepoint module list mutex protects the local module list.
|
|
*/
|
|
static DEFINE_MUTEX(tracepoint_module_list_mutex);
|
|
|
|
/* Local list of struct tp_module */
|
|
static LIST_HEAD(tracepoint_module_list);
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
/*
|
|
* tracepoints_mutex protects the builtin and module tracepoints.
|
|
* tracepoints_mutex nests inside tracepoint_module_list_mutex.
|
|
*/
|
|
static DEFINE_MUTEX(tracepoints_mutex);
|
|
|
|
/*
|
|
* Note about RCU :
|
|
* It is used to delay the free of multiple probes array until a quiescent
|
|
* state is reached.
|
|
*/
|
|
struct tp_probes {
|
|
struct rcu_head rcu;
|
|
struct tracepoint_func probes[0];
|
|
};
|
|
|
|
static inline void *allocate_probes(int count)
|
|
{
|
|
struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func)
|
|
+ sizeof(struct tp_probes), GFP_KERNEL);
|
|
return p == NULL ? NULL : p->probes;
|
|
}
|
|
|
|
static void rcu_free_old_probes(struct rcu_head *head)
|
|
{
|
|
kfree(container_of(head, struct tp_probes, rcu));
|
|
}
|
|
|
|
static inline void release_probes(struct tracepoint_func *old)
|
|
{
|
|
if (old) {
|
|
struct tp_probes *tp_probes = container_of(old,
|
|
struct tp_probes, probes[0]);
|
|
call_rcu_sched(&tp_probes->rcu, rcu_free_old_probes);
|
|
}
|
|
}
|
|
|
|
static void debug_print_probes(struct tracepoint_func *funcs)
|
|
{
|
|
int i;
|
|
|
|
if (!tracepoint_debug || !funcs)
|
|
return;
|
|
|
|
for (i = 0; funcs[i].func; i++)
|
|
printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
|
|
}
|
|
|
|
static struct tracepoint_func *
|
|
func_add(struct tracepoint_func **funcs, struct tracepoint_func *tp_func,
|
|
int prio)
|
|
{
|
|
struct tracepoint_func *old, *new;
|
|
int nr_probes = 0;
|
|
int pos = -1;
|
|
|
|
if (WARN_ON(!tp_func->func))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
debug_print_probes(*funcs);
|
|
old = *funcs;
|
|
if (old) {
|
|
/* (N -> N+1), (N != 0, 1) probes */
|
|
for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
|
|
/* Insert before probes of lower priority */
|
|
if (pos < 0 && old[nr_probes].prio < prio)
|
|
pos = nr_probes;
|
|
if (old[nr_probes].func == tp_func->func &&
|
|
old[nr_probes].data == tp_func->data)
|
|
return ERR_PTR(-EEXIST);
|
|
}
|
|
}
|
|
/* + 2 : one for new probe, one for NULL func */
|
|
new = allocate_probes(nr_probes + 2);
|
|
if (new == NULL)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (old) {
|
|
if (pos < 0) {
|
|
pos = nr_probes;
|
|
memcpy(new, old, nr_probes * sizeof(struct tracepoint_func));
|
|
} else {
|
|
/* Copy higher priority probes ahead of the new probe */
|
|
memcpy(new, old, pos * sizeof(struct tracepoint_func));
|
|
/* Copy the rest after it. */
|
|
memcpy(new + pos + 1, old + pos,
|
|
(nr_probes - pos) * sizeof(struct tracepoint_func));
|
|
}
|
|
} else
|
|
pos = 0;
|
|
new[pos] = *tp_func;
|
|
new[nr_probes + 1].func = NULL;
|
|
*funcs = new;
|
|
debug_print_probes(*funcs);
|
|
return old;
|
|
}
|
|
|
|
static void *func_remove(struct tracepoint_func **funcs,
|
|
struct tracepoint_func *tp_func)
|
|
{
|
|
int nr_probes = 0, nr_del = 0, i;
|
|
struct tracepoint_func *old, *new;
|
|
|
|
old = *funcs;
|
|
|
|
if (!old)
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
debug_print_probes(*funcs);
|
|
/* (N -> M), (N > 1, M >= 0) probes */
|
|
if (tp_func->func) {
|
|
for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
|
|
if (old[nr_probes].func == tp_func->func &&
|
|
old[nr_probes].data == tp_func->data)
|
|
nr_del++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If probe is NULL, then nr_probes = nr_del = 0, and then the
|
|
* entire entry will be removed.
|
|
*/
|
|
if (nr_probes - nr_del == 0) {
|
|
/* N -> 0, (N > 1) */
|
|
*funcs = NULL;
|
|
debug_print_probes(*funcs);
|
|
return old;
|
|
} else {
|
|
int j = 0;
|
|
/* N -> M, (N > 1, M > 0) */
|
|
/* + 1 for NULL */
|
|
new = allocate_probes(nr_probes - nr_del + 1);
|
|
if (new == NULL)
|
|
return ERR_PTR(-ENOMEM);
|
|
for (i = 0; old[i].func; i++)
|
|
if (old[i].func != tp_func->func
|
|
|| old[i].data != tp_func->data)
|
|
new[j++] = old[i];
|
|
new[nr_probes - nr_del].func = NULL;
|
|
*funcs = new;
|
|
}
|
|
debug_print_probes(*funcs);
|
|
return old;
|
|
}
|
|
|
|
/*
|
|
* Add the probe function to a tracepoint.
|
|
*/
|
|
static int tracepoint_add_func(struct tracepoint *tp,
|
|
struct tracepoint_func *func, int prio)
|
|
{
|
|
struct tracepoint_func *old, *tp_funcs;
|
|
int ret;
|
|
|
|
if (tp->regfunc && !static_key_enabled(&tp->key)) {
|
|
ret = tp->regfunc();
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
tp_funcs = rcu_dereference_protected(tp->funcs,
|
|
lockdep_is_held(&tracepoints_mutex));
|
|
old = func_add(&tp_funcs, func, prio);
|
|
if (IS_ERR(old)) {
|
|
WARN_ON_ONCE(1);
|
|
return PTR_ERR(old);
|
|
}
|
|
|
|
/*
|
|
* rcu_assign_pointer has a smp_wmb() which makes sure that the new
|
|
* probe callbacks array is consistent before setting a pointer to it.
|
|
* This array is referenced by __DO_TRACE from
|
|
* include/linux/tracepoints.h. A matching smp_read_barrier_depends()
|
|
* is used.
|
|
*/
|
|
rcu_assign_pointer(tp->funcs, tp_funcs);
|
|
if (!static_key_enabled(&tp->key))
|
|
static_key_slow_inc(&tp->key);
|
|
release_probes(old);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remove a probe function from a tracepoint.
|
|
* Note: only waiting an RCU period after setting elem->call to the empty
|
|
* function insures that the original callback is not used anymore. This insured
|
|
* by preempt_disable around the call site.
|
|
*/
|
|
static int tracepoint_remove_func(struct tracepoint *tp,
|
|
struct tracepoint_func *func)
|
|
{
|
|
struct tracepoint_func *old, *tp_funcs;
|
|
|
|
tp_funcs = rcu_dereference_protected(tp->funcs,
|
|
lockdep_is_held(&tracepoints_mutex));
|
|
old = func_remove(&tp_funcs, func);
|
|
if (IS_ERR(old)) {
|
|
WARN_ON_ONCE(1);
|
|
return PTR_ERR(old);
|
|
}
|
|
|
|
if (!tp_funcs) {
|
|
/* Removed last function */
|
|
if (tp->unregfunc && static_key_enabled(&tp->key))
|
|
tp->unregfunc();
|
|
|
|
if (static_key_enabled(&tp->key))
|
|
static_key_slow_dec(&tp->key);
|
|
}
|
|
rcu_assign_pointer(tp->funcs, tp_funcs);
|
|
release_probes(old);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tracepoint_probe_register - Connect a probe to a tracepoint
|
|
* @tp: tracepoint
|
|
* @probe: probe handler
|
|
* @data: tracepoint data
|
|
* @prio: priority of this function over other registered functions
|
|
*
|
|
* Returns 0 if ok, error value on error.
|
|
* Note: if @tp is within a module, the caller is responsible for
|
|
* unregistering the probe before the module is gone. This can be
|
|
* performed either with a tracepoint module going notifier, or from
|
|
* within module exit functions.
|
|
*/
|
|
int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
|
|
void *data, int prio)
|
|
{
|
|
struct tracepoint_func tp_func;
|
|
int ret;
|
|
|
|
mutex_lock(&tracepoints_mutex);
|
|
tp_func.func = probe;
|
|
tp_func.data = data;
|
|
tp_func.prio = prio;
|
|
ret = tracepoint_add_func(tp, &tp_func, prio);
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio);
|
|
|
|
/**
|
|
* tracepoint_probe_register - Connect a probe to a tracepoint
|
|
* @tp: tracepoint
|
|
* @probe: probe handler
|
|
* @data: tracepoint data
|
|
* @prio: priority of this function over other registered functions
|
|
*
|
|
* Returns 0 if ok, error value on error.
|
|
* Note: if @tp is within a module, the caller is responsible for
|
|
* unregistering the probe before the module is gone. This can be
|
|
* performed either with a tracepoint module going notifier, or from
|
|
* within module exit functions.
|
|
*/
|
|
int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data)
|
|
{
|
|
return tracepoint_probe_register_prio(tp, probe, data, TRACEPOINT_DEFAULT_PRIO);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
|
|
|
|
/**
|
|
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
|
|
* @tp: tracepoint
|
|
* @probe: probe function pointer
|
|
* @data: tracepoint data
|
|
*
|
|
* Returns 0 if ok, error value on error.
|
|
*/
|
|
int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
|
|
{
|
|
struct tracepoint_func tp_func;
|
|
int ret;
|
|
|
|
mutex_lock(&tracepoints_mutex);
|
|
tp_func.func = probe;
|
|
tp_func.data = data;
|
|
ret = tracepoint_remove_func(tp, &tp_func);
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
|
|
|
|
#ifdef CONFIG_MODULES
|
|
bool trace_module_has_bad_taint(struct module *mod)
|
|
{
|
|
return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
|
|
(1 << TAINT_UNSIGNED_MODULE));
|
|
}
|
|
|
|
static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
|
|
|
|
/**
|
|
* register_tracepoint_notifier - register tracepoint coming/going notifier
|
|
* @nb: notifier block
|
|
*
|
|
* Notifiers registered with this function are called on module
|
|
* coming/going with the tracepoint_module_list_mutex held.
|
|
* The notifier block callback should expect a "struct tp_module" data
|
|
* pointer.
|
|
*/
|
|
int register_tracepoint_module_notifier(struct notifier_block *nb)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
int ret;
|
|
|
|
mutex_lock(&tracepoint_module_list_mutex);
|
|
ret = blocking_notifier_chain_register(&tracepoint_notify_list, nb);
|
|
if (ret)
|
|
goto end;
|
|
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
|
|
(void) nb->notifier_call(nb, MODULE_STATE_COMING, tp_mod);
|
|
end:
|
|
mutex_unlock(&tracepoint_module_list_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_tracepoint_module_notifier);
|
|
|
|
/**
|
|
* unregister_tracepoint_notifier - unregister tracepoint coming/going notifier
|
|
* @nb: notifier block
|
|
*
|
|
* The notifier block callback should expect a "struct tp_module" data
|
|
* pointer.
|
|
*/
|
|
int unregister_tracepoint_module_notifier(struct notifier_block *nb)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
int ret;
|
|
|
|
mutex_lock(&tracepoint_module_list_mutex);
|
|
ret = blocking_notifier_chain_unregister(&tracepoint_notify_list, nb);
|
|
if (ret)
|
|
goto end;
|
|
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
|
|
(void) nb->notifier_call(nb, MODULE_STATE_GOING, tp_mod);
|
|
end:
|
|
mutex_unlock(&tracepoint_module_list_mutex);
|
|
return ret;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
|
|
|
|
/*
|
|
* Ensure the tracer unregistered the module's probes before the module
|
|
* teardown is performed. Prevents leaks of probe and data pointers.
|
|
*/
|
|
static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
|
|
struct tracepoint * const *end)
|
|
{
|
|
struct tracepoint * const *iter;
|
|
|
|
if (!begin)
|
|
return;
|
|
for (iter = begin; iter < end; iter++)
|
|
WARN_ON_ONCE((*iter)->funcs);
|
|
}
|
|
|
|
static int tracepoint_module_coming(struct module *mod)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
int ret = 0;
|
|
|
|
if (!mod->num_tracepoints)
|
|
return 0;
|
|
|
|
/*
|
|
* We skip modules that taint the kernel, especially those with different
|
|
* module headers (for forced load), to make sure we don't cause a crash.
|
|
* Staging, out-of-tree, and unsigned GPL modules are fine.
|
|
*/
|
|
if (trace_module_has_bad_taint(mod))
|
|
return 0;
|
|
mutex_lock(&tracepoint_module_list_mutex);
|
|
tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
|
|
if (!tp_mod) {
|
|
ret = -ENOMEM;
|
|
goto end;
|
|
}
|
|
tp_mod->mod = mod;
|
|
list_add_tail(&tp_mod->list, &tracepoint_module_list);
|
|
blocking_notifier_call_chain(&tracepoint_notify_list,
|
|
MODULE_STATE_COMING, tp_mod);
|
|
end:
|
|
mutex_unlock(&tracepoint_module_list_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static void tracepoint_module_going(struct module *mod)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
|
|
if (!mod->num_tracepoints)
|
|
return;
|
|
|
|
mutex_lock(&tracepoint_module_list_mutex);
|
|
list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
|
|
if (tp_mod->mod == mod) {
|
|
blocking_notifier_call_chain(&tracepoint_notify_list,
|
|
MODULE_STATE_GOING, tp_mod);
|
|
list_del(&tp_mod->list);
|
|
kfree(tp_mod);
|
|
/*
|
|
* Called the going notifier before checking for
|
|
* quiescence.
|
|
*/
|
|
tp_module_going_check_quiescent(mod->tracepoints_ptrs,
|
|
mod->tracepoints_ptrs + mod->num_tracepoints);
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* In the case of modules that were tainted at "coming", we'll simply
|
|
* walk through the list without finding it. We cannot use the "tainted"
|
|
* flag on "going", in case a module taints the kernel only after being
|
|
* loaded.
|
|
*/
|
|
mutex_unlock(&tracepoint_module_list_mutex);
|
|
}
|
|
|
|
static int tracepoint_module_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
int ret = 0;
|
|
|
|
switch (val) {
|
|
case MODULE_STATE_COMING:
|
|
ret = tracepoint_module_coming(mod);
|
|
break;
|
|
case MODULE_STATE_LIVE:
|
|
break;
|
|
case MODULE_STATE_GOING:
|
|
tracepoint_module_going(mod);
|
|
break;
|
|
case MODULE_STATE_UNFORMED:
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static struct notifier_block tracepoint_module_nb = {
|
|
.notifier_call = tracepoint_module_notify,
|
|
.priority = 0,
|
|
};
|
|
|
|
static __init int init_tracepoints(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_module_notifier(&tracepoint_module_nb);
|
|
if (ret)
|
|
pr_warn("Failed to register tracepoint module enter notifier\n");
|
|
|
|
return ret;
|
|
}
|
|
__initcall(init_tracepoints);
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
static void for_each_tracepoint_range(struct tracepoint * const *begin,
|
|
struct tracepoint * const *end,
|
|
void (*fct)(struct tracepoint *tp, void *priv),
|
|
void *priv)
|
|
{
|
|
struct tracepoint * const *iter;
|
|
|
|
if (!begin)
|
|
return;
|
|
for (iter = begin; iter < end; iter++)
|
|
fct(*iter, priv);
|
|
}
|
|
|
|
/**
|
|
* for_each_kernel_tracepoint - iteration on all kernel tracepoints
|
|
* @fct: callback
|
|
* @priv: private data
|
|
*/
|
|
void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
|
|
void *priv)
|
|
{
|
|
for_each_tracepoint_range(__start___tracepoints_ptrs,
|
|
__stop___tracepoints_ptrs, fct, priv);
|
|
}
|
|
EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint);
|
|
|
|
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
|
|
|
|
/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
|
|
static int sys_tracepoint_refcount;
|
|
|
|
int syscall_regfunc(void)
|
|
{
|
|
struct task_struct *p, *t;
|
|
|
|
if (!sys_tracepoint_refcount) {
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(p, t) {
|
|
set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
sys_tracepoint_refcount++;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void syscall_unregfunc(void)
|
|
{
|
|
struct task_struct *p, *t;
|
|
|
|
sys_tracepoint_refcount--;
|
|
if (!sys_tracepoint_refcount) {
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(p, t) {
|
|
clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
}
|
|
#endif
|