Thread (31 messages) 31 messages, 3 authors, 2012-01-24

[27/27] kprobes: initialize before using a hlist

From: Greg KH <gregkh@suse.de>
Date: 2012-01-23 23:46:36
Also in: lkml

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Ananth N Mavinakayanahalli <redacted>

commit d496aab567e7e52b3e974c9192a5de6e77dce32c upstream.

Commit ef53d9c5e ("kprobes: improve kretprobe scalability with hashed
locking") 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 [off-list ref]
Acked-by: Jim Keniston <redacted>
Signed-off-by: Ananth N Mavinakayanahalli <redacted>
Acked-by: Masami Hiramatsu <redacted>
Cc: Srinivasa D S <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 kernel/kprobes.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -466,6 +466,7 @@ 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);
@@ -474,7 +475,6 @@ 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);

Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help