[PATCH] kprobes-changed-from-using-spinlock-to-mutex fix
Based on some feedback from Oleg Nesterov, I have made few changes to
previously posted patch.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f14ccd3..f1c0e61 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -431,7 +431,7 @@
copy_kprobe(old_p, p);
ret = add_new_kprobe(old_p, p);
} else {
- ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC);
+ ap = kcalloc(1, sizeof(struct kprobe), GFP_KERNEL);
if (!ap)
return -ENOMEM;
add_aggr_kprobe(ap, old_p);
@@ -491,7 +491,8 @@
void __kprobes unregister_kprobe(struct kprobe *p)
{
struct module *mod;
- struct kprobe *old_p, *cleanup_p;
+ struct kprobe *old_p, *list_p;
+ int cleanup_p;
down(&kprobe_mutex);
old_p = get_kprobe(p->addr);
@@ -499,22 +500,25 @@
up(&kprobe_mutex);
return;
}
-
- if ((old_p->pre_handler == aggr_pre_handler) &&
+ 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;
+ up(&kprobe_mutex);
+ return;
+ }
+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)) {
- /* Only one element in the aggregate list */
+ (p->list.prev == &old_p->list))) {
+ /* Only probe on the hash list */
arch_disarm_kprobe(p);
hlist_del_rcu(&old_p->hlist);
- cleanup_p = old_p;
- } else if (old_p == p) {
- /* Only one kprobe element in the hash list */
- arch_disarm_kprobe(p);
- hlist_del_rcu(&p->hlist);
- cleanup_p = p;
+ cleanup_p = 1;
} else {
list_del_rcu(&p->list);
- cleanup_p = NULL;
+ cleanup_p = 0;
}
up(&kprobe_mutex);
@@ -524,7 +528,7 @@
module_put(mod);
if (cleanup_p) {
- if (cleanup_p->pre_handler == aggr_pre_handler) {
+ if (p != old_p) {
list_del_rcu(&p->list);
kfree(old_p);
}