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kprobes: initialize before using a hlist

PATCH Superseded Ananth N Mavinakayanahalli 1 participant 1 message Jan 9, 2012 kprobes

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Ananth N Mavinakayanahalli

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PATCH 1/1 kprobes: initialize before using a hlist

From: Ananth N Mavinakayanahalli <[email protected]>

Commit ef53d9c5e introduced a bug where we can potentially leak kretprobe_instances since we initialize a hlist head after having used it.

Initialize the hlist head before using it.

Reported by: Jim Keniston <[email protected]>

Signed-off-by Ananth N Mavinakayanahalli <[email protected]>
CC Masami Hiramatsu <[email protected]>
CC <[email protected]>
---
 kernel/kprobes.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
kernel/kprobes.c +1 -1
Index: linux-3.2/kernel/kprobes.c
===================================================================
@@ -1077,6 +1077,7 @@ void __kprobes kprobe_flush_task(struct 
 		/* Early boot.  kretprobe_table_locks not yet initialized. */
 		return;
 
+	INIT_HLIST_HEAD(&empty_rp);
 	hash = hash_ptr(tk, KPROBE_HASH_BITS);
 	head = &kretprobe_inst_table[hash];
 	kretprobe_table_lock(hash, &flags);

@@ -1085,7 +1086,6 @@ void __kprobes kprobe_flush_task(struct 
 			recycle_rp_inst(ri, &empty_rp);
 	}
 	kretprobe_table_unlock(hash, &flags);
-	INIT_HLIST_HEAD(&empty_rp);
 	hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
 		hlist_del(&ri->hlist);
 		kfree(ri);