From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755972AbcCWQvF (ORCPT ); Wed, 23 Mar 2016 12:51:05 -0400 Received: from mga14.intel.com ([192.55.52.115]:52745 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753439AbcCWQvD (ORCPT ); Wed, 23 Mar 2016 12:51:03 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,383,1455004800"; d="scan'208";a="770004228" From: Tony Luck Date: Wed, 23 Mar 2016 09:14:40 -0700 Subject: [PATCH] x86/mce: Avoid using object after free in genpool. To: Borislav Petkov Cc: linux-kernel@vger.kernel.org, "Chen, Gong" Message-Id: <0205920@agluck-desk.sc.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we loop over all queued machine check error records to pass them to the registered notifiers we use llist_for_each_entry(). But the loop calls gen_pool_free() for the entry in the body of the loop - and then the iterator looks at node->next after the free. Use llist_for_each_entry_safe() instead. Cc: stable@vger.kernel.org Signed-off-by: Tony Luck --- arch/x86/kernel/cpu/mcheck/mce-genpool.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce-genpool.c b/arch/x86/kernel/cpu/mcheck/mce-genpool.c index 0a850100c594..2658e2af74ec 100644 --- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c +++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c @@ -29,7 +29,7 @@ static char gen_pool_buf[MCE_POOLSZ]; void mce_gen_pool_process(void) { struct llist_node *head; - struct mce_evt_llist *node; + struct mce_evt_llist *node, *tmp; struct mce *mce; head = llist_del_all(&mce_event_llist); @@ -37,7 +37,7 @@ void mce_gen_pool_process(void) return; head = llist_reverse_order(head); - llist_for_each_entry(node, head, llnode) { + llist_for_each_entry_safe(node, tmp, head, llnode) { mce = &node->mce; atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce); gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node)); -- 2.5.0