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authorMasami Hiramatsu <mhiramat@redhat.com>2008-04-28 02:14:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:32 -0700
commit9861668f747895608cea425f8457989d8dd2edf2 (patch)
treedb5dad352826407afb549a8cfa44d4c66823af15 /kernel/kprobes.c
parent99602572812442d47403d85f376ad51298dd82a6 (diff)
downloadlinux-2.6.34-ux500-9861668f747895608cea425f8457989d8dd2edf2.tar.gz
kprobes: add (un)register_kprobes for batch registration
Introduce unregister_/register_kprobes() for kprobe batch registration. This can reduce waiting time for synchronized_sched() when a lot of probes have to be unregistered at once. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: David Miller <davem@davemloft.net> Cc: "Frank Ch. Eigler" <fche@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c124
1 files changed, 87 insertions, 37 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f02a4311768..76275fc025a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -580,6 +580,7 @@ static int __kprobes __register_kprobe(struct kprobe *p,
}
p->nmissed = 0;
+ INIT_LIST_HEAD(&p->list);
mutex_lock(&kprobe_mutex);
old_p = get_kprobe(p->addr);
if (old_p) {
@@ -606,35 +607,28 @@ out:
return ret;
}
-int __kprobes register_kprobe(struct kprobe *p)
-{
- return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
-}
-
-void __kprobes unregister_kprobe(struct kprobe *p)
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __kprobes __unregister_kprobe_top(struct kprobe *p)
{
- struct module *mod;
struct kprobe *old_p, *list_p;
- int cleanup_p;
- mutex_lock(&kprobe_mutex);
old_p = get_kprobe(p->addr);
- if (unlikely(!old_p)) {
- mutex_unlock(&kprobe_mutex);
- return;
- }
+ if (unlikely(!old_p))
+ return -EINVAL;
+
if (p != old_p) {
list_for_each_entry_rcu(list_p, &old_p->list, list)
if (list_p == p)
/* kprobe p is a valid probe */
goto valid_p;
- mutex_unlock(&kprobe_mutex);
- return;
+ return -EINVAL;
}
valid_p:
if (old_p == p ||
(old_p->pre_handler == aggr_pre_handler &&
- p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
+ list_is_singular(&old_p->list))) {
/*
* Only probe on the hash list. Disarm only if kprobes are
* enabled - otherwise, the breakpoint would already have
@@ -643,43 +637,97 @@ valid_p:
if (kprobe_enabled)
arch_disarm_kprobe(p);
hlist_del_rcu(&old_p->hlist);
- cleanup_p = 1;
} else {
+ if (p->break_handler)
+ old_p->break_handler = NULL;
+ if (p->post_handler) {
+ list_for_each_entry_rcu(list_p, &old_p->list, list) {
+ if ((list_p != p) && (list_p->post_handler))
+ goto noclean;
+ }
+ old_p->post_handler = NULL;
+ }
+noclean:
list_del_rcu(&p->list);
- cleanup_p = 0;
}
+ return 0;
+}
- mutex_unlock(&kprobe_mutex);
+static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
+{
+ struct module *mod;
+ struct kprobe *old_p;
- synchronize_sched();
if (p->mod_refcounted) {
mod = module_text_address((unsigned long)p->addr);
if (mod)
module_put(mod);
}
- if (cleanup_p) {
- if (p != old_p) {
- list_del_rcu(&p->list);
+ if (list_empty(&p->list) || list_is_singular(&p->list)) {
+ if (!list_empty(&p->list)) {
+ /* "p" is the last child of an aggr_kprobe */
+ old_p = list_entry(p->list.next, struct kprobe, list);
+ list_del(&p->list);
kfree(old_p);
}
arch_remove_kprobe(p);
- } else {
- mutex_lock(&kprobe_mutex);
- if (p->break_handler)
- old_p->break_handler = NULL;
- if (p->post_handler){
- list_for_each_entry_rcu(list_p, &old_p->list, list){
- if (list_p->post_handler){
- cleanup_p = 2;
- break;
- }
- }
- if (cleanup_p == 0)
- old_p->post_handler = NULL;
+ }
+}
+
+static int __register_kprobes(struct kprobe **kps, int num,
+ unsigned long called_from)
+{
+ int i, ret = 0;
+
+ if (num <= 0)
+ return -EINVAL;
+ for (i = 0; i < num; i++) {
+ ret = __register_kprobe(kps[i], called_from);
+ if (ret < 0 && i > 0) {
+ unregister_kprobes(kps, i);
+ break;
}
- mutex_unlock(&kprobe_mutex);
}
+ return ret;
+}
+
+/*
+ * Registration and unregistration functions for kprobe.
+ */
+int __kprobes register_kprobe(struct kprobe *p)
+{
+ return __register_kprobes(&p, 1,
+ (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kprobe(struct kprobe *p)
+{
+ unregister_kprobes(&p, 1);
+}
+
+int __kprobes register_kprobes(struct kprobe **kps, int num)
+{
+ return __register_kprobes(kps, num,
+ (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kprobes(struct kprobe **kps, int num)
+{
+ int i;
+
+ if (num <= 0)
+ return;
+ mutex_lock(&kprobe_mutex);
+ for (i = 0; i < num; i++)
+ if (__unregister_kprobe_top(kps[i]) < 0)
+ kps[i]->addr = NULL;
+ mutex_unlock(&kprobe_mutex);
+
+ synchronize_sched();
+ for (i = 0; i < num; i++)
+ if (kps[i]->addr)
+ __unregister_kprobe_bottom(kps[i]);
}
static struct notifier_block kprobe_exceptions_nb = {
@@ -1118,6 +1166,8 @@ module_init(init_kprobes);
EXPORT_SYMBOL_GPL(register_kprobe);
EXPORT_SYMBOL_GPL(unregister_kprobe);
+EXPORT_SYMBOL_GPL(register_kprobes);
+EXPORT_SYMBOL_GPL(unregister_kprobes);
EXPORT_SYMBOL_GPL(register_jprobe);
EXPORT_SYMBOL_GPL(unregister_jprobe);
#ifdef CONFIG_KPROBES