kprobes: cleanup to separate probe-able check
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>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7a8a122..6137fe3 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1313,13 +1313,61 @@
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 @@
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 @@
module_put(probed_mod);
return ret;
-
-cannot_probe:
- preempt_enable();
- jump_label_unlock();
- return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);
