X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fkprobes.c;h=1fbf466a29aab6ca0dfe1cf6e5d6ac16fba546d8;hb=2697c5e1f799f201366d5fd7d25e96a21587f1a9;hp=3ea6325228dafd293b8421ac4d47ea49457b17a0;hpb=e7de369050534025b33aab1033358bf47a577e4d;p=linux-2.6

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3ea6325228..1fbf466a29 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -48,7 +48,7 @@
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
-DECLARE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
+DEFINE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
 DEFINE_SPINLOCK(kretprobe_lock);	/* Protects kretprobe_inst_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 
@@ -323,10 +323,10 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
 }
 
 /*
- * This function is called from exit_thread or flush_thread when task tk's
- * stack is being recycled so that we can recycle any function-return probe
- * instances associated with this task. These left over instances represent
- * probed functions that have been called but will never return.
+ * This function is called from finish_task_switch when task tk becomes dead,
+ * so that we can recycle any function-return probe instances associated
+ * with this task. These left over instances represent probed functions
+ * that have been called but will never return.
  */
 void __kprobes kprobe_flush_task(struct task_struct *tk)
 {
@@ -336,7 +336,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
 	unsigned long flags = 0;
 
 	spin_lock_irqsave(&kretprobe_lock, flags);
-        head = kretprobe_inst_table_head(current);
+        head = kretprobe_inst_table_head(tk);
         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
                 if (ri->task == tk)
                         recycle_rp_inst(ri);
@@ -344,23 +344,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
 	spin_unlock_irqrestore(&kretprobe_lock, flags);
 }
 
-/*
- * This kprobe pre_handler is registered with every kretprobe. When probe
- * hits it will set up the return probe.
- */
-static int __kprobes pre_handler_kretprobe(struct kprobe *p,
-					   struct pt_regs *regs)
-{
-	struct kretprobe *rp = container_of(p, struct kretprobe, kp);
-	unsigned long flags = 0;
-
-	/*TODO: consider to only swap the RA after the last pre_handler fired */
-	spin_lock_irqsave(&kretprobe_lock, flags);
-	arch_prepare_kretprobe(rp, regs);
-	spin_unlock_irqrestore(&kretprobe_lock, flags);
-	return 0;
-}
-
 static inline void free_rp_inst(struct kretprobe *rp)
 {
 	struct kretprobe_instance *ri;
@@ -477,7 +460,7 @@ static int __kprobes __register_kprobe(struct kprobe *p,
 	}
 
 	p->nmissed = 0;
-	down(&kprobe_mutex);
+	mutex_lock(&kprobe_mutex);
 	old_p = get_kprobe(p->addr);
 	if (old_p) {
 		ret = register_aggr_kprobe(old_p, p);
@@ -494,7 +477,7 @@ static int __kprobes __register_kprobe(struct kprobe *p,
   	arch_arm_kprobe(p);
 
 out:
-	up(&kprobe_mutex);
+	mutex_unlock(&kprobe_mutex);
 
 	if (ret && probed_mod)
 		module_put(probed_mod);
@@ -513,10 +496,10 @@ void __kprobes unregister_kprobe(struct kprobe *p)
 	struct kprobe *old_p, *list_p;
 	int cleanup_p;
 
-	down(&kprobe_mutex);
+	mutex_lock(&kprobe_mutex);
 	old_p = get_kprobe(p->addr);
 	if (unlikely(!old_p)) {
-		up(&kprobe_mutex);
+		mutex_unlock(&kprobe_mutex);
 		return;
 	}
 	if (p != old_p) {
@@ -524,7 +507,7 @@ void __kprobes unregister_kprobe(struct kprobe *p)
 			if (list_p == p)
 			/* kprobe p is a valid probe */
 				goto valid_p;
-		up(&kprobe_mutex);
+		mutex_unlock(&kprobe_mutex);
 		return;
 	}
 valid_p:
@@ -540,7 +523,7 @@ valid_p:
 		cleanup_p = 0;
 	}
 
-	up(&kprobe_mutex);
+	mutex_unlock(&kprobe_mutex);
 
 	synchronize_sched();
 	if (p->mod_refcounted &&
@@ -578,6 +561,23 @@ void __kprobes unregister_jprobe(struct jprobe *jp)
 
 #ifdef ARCH_SUPPORTS_KRETPROBES
 
+/*
+ * This kprobe pre_handler is registered with every kretprobe. When probe
+ * hits it will set up the return probe.
+ */
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+					   struct pt_regs *regs)
+{
+	struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+	unsigned long flags = 0;
+
+	/*TODO: consider to only swap the RA after the last pre_handler fired */
+	spin_lock_irqsave(&kretprobe_lock, flags);
+	arch_prepare_kretprobe(rp, regs);
+	spin_unlock_irqrestore(&kretprobe_lock, flags);
+	return 0;
+}
+
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
 	int ret = 0;
@@ -585,6 +585,9 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 	int i;
 
 	rp->kp.pre_handler = pre_handler_kretprobe;
+	rp->kp.post_handler = NULL;
+	rp->kp.fault_handler = NULL;
+	rp->kp.break_handler = NULL;
 
 	/* Pre-allocate memory for max kretprobe instances */
 	if (rp->maxactive <= 0) {
@@ -631,12 +634,12 @@ void __kprobes unregister_kretprobe(struct kretprobe *rp)
 	unregister_kprobe(&rp->kp);
 	/* No race here */
 	spin_lock_irqsave(&kretprobe_lock, flags);
-	free_rp_inst(rp);
 	while ((ri = get_used_rp_inst(rp)) != NULL) {
 		ri->rp = NULL;
 		hlist_del(&ri->uflist);
 	}
 	spin_unlock_irqrestore(&kretprobe_lock, flags);
+	free_rp_inst(rp);
 }
 
 static int __init init_kprobes(void)