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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2012-01-20 14:34:04 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-25 16:13:57 -0800
commit6ee7663e972835367a550bd6b9fecc1a9dc14ce1 (patch)
treedbce6c001ccf5319ccbd5a0b2b45a4f75756fa65
parentbdac3a105a1c8fdf89ea15404ad5c7bcec73d37a (diff)
downloadlwn-6ee7663e972835367a550bd6b9fecc1a9dc14ce1.tar.gz
lwn-6ee7663e972835367a550bd6b9fecc1a9dc14ce1.zip
kprobes: initialize before using a hlist
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 <jkenisto@us.ibm.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Srinivasa D S <srinivasa@in.ibm.com> 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>
-rw-r--r--kernel/kprobes.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e5d84644823b..52fd0499573f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1077,6 +1077,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
/* 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 task_struct *tk)
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);