Commit d496aab5 authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Linus Torvalds

kprobes: initialize before using a hlist

Commit ef53d9c5 ("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: default avatarJim Keniston <jkenisto@us.ibm.com>
Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srinivasa D S <srinivasa@in.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2a4e64b8
...@@ -1077,6 +1077,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) ...@@ -1077,6 +1077,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
/* Early boot. kretprobe_table_locks not yet initialized. */ /* Early boot. kretprobe_table_locks not yet initialized. */
return; return;
INIT_HLIST_HEAD(&empty_rp);
hash = hash_ptr(tk, KPROBE_HASH_BITS); hash = hash_ptr(tk, KPROBE_HASH_BITS);
head = &kretprobe_inst_table[hash]; head = &kretprobe_inst_table[hash];
kretprobe_table_lock(hash, &flags); kretprobe_table_lock(hash, &flags);
...@@ -1085,7 +1086,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) ...@@ -1085,7 +1086,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
recycle_rp_inst(ri, &empty_rp); recycle_rp_inst(ri, &empty_rp);
} }
kretprobe_table_unlock(hash, &flags); kretprobe_table_unlock(hash, &flags);
INIT_HLIST_HEAD(&empty_rp);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist); hlist_del(&ri->hlist);
kfree(ri); kfree(ri);
......
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