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kprobes: cleanup to separate probe-able check

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Separate probe-able address checking code from
register_kprobe().

Link: http://lkml.kernel.org/r/20120605102820.27845.90133.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2012-06-05 19:28:20 +09:00 committed by Steven Rostedt
parent 72ef3794c5
commit f7fa6ef0de
1 changed files with 54 additions and 46 deletions
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100
kernel/kprobes.c
View file

@ -1313,13 +1313,61 @@ static inline int check_kprobe_rereg(struct kprobe *p)
return ret;
}
int __kprobes register_kprobe(struct kprobe *p)
static __kprobes int check_kprobe_address_safe(struct kprobe *p,
struct module **probed_mod)
{
int ret = 0;
jump_label_lock();
preempt_disable();
/* Ensure it is not in reserved area nor out of text */
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr) ||
ftrace_text_reserved(p->addr, p->addr) ||
jump_label_text_reserved(p->addr, p->addr)) {
ret = -EINVAL;
goto out;
}
/* Check if are we probing a module */
*probed_mod = __module_text_address((unsigned long) p->addr);
if (*probed_mod) {
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
if (unlikely(!try_module_get(*probed_mod))) {
ret = -ENOENT;
goto out;
}
/*
* If the module freed .init.text, we couldn't insert
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
(*probed_mod)->state != MODULE_STATE_COMING) {
module_put(*probed_mod);
*probed_mod = NULL;
ret = -ENOENT;
}
}
out:
preempt_enable();
jump_label_unlock();
return ret;
}
int __kprobes register_kprobe(struct kprobe *p)
{
int ret;
struct kprobe *old_p;
struct module *probed_mod;
kprobe_opcode_t *addr;
/* Adjust probe address from symbol */
addr = kprobe_addr(p);
if (IS_ERR(addr))
return PTR_ERR(addr);
@ -1329,51 +1377,16 @@ int __kprobes register_kprobe(struct kprobe *p)
if (ret)
return ret;
jump_label_lock();
preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr) ||
ftrace_text_reserved(p->addr, p->addr) ||
jump_label_text_reserved(p->addr, p->addr)) {
ret = -EINVAL;
goto cannot_probe;
}
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
p->flags &= KPROBE_FLAG_DISABLED;
/*
* Check if are we probing a module.
*/
probed_mod = __module_text_address((unsigned long) p->addr);
if (probed_mod) {
/* Return -ENOENT if fail. */
ret = -ENOENT;
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
if (unlikely(!try_module_get(probed_mod)))
goto cannot_probe;
/*
* If the module freed .init.text, we couldn't insert
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, probed_mod) &&
probed_mod->state != MODULE_STATE_COMING) {
module_put(probed_mod);
goto cannot_probe;
}
/* ret will be updated by following code */
}
preempt_enable();
jump_label_unlock();
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
mutex_lock(&kprobe_mutex);
ret = check_kprobe_address_safe(p, &probed_mod);
if (ret)
return ret;
mutex_lock(&kprobe_mutex);
jump_label_lock(); /* needed to call jump_label_text_reserved() */
get_online_cpus(); /* For avoiding text_mutex deadlock. */
@ -1410,11 +1423,6 @@ out:
module_put(probed_mod);
return ret;
cannot_probe:
preempt_enable();
jump_label_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);