From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933215AbcDFIGU (ORCPT ); Wed, 6 Apr 2016 04:06:20 -0400 Received: from mail.skyhub.de ([78.46.96.112]:39234 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753400AbcDFIFX (ORCPT ); Wed, 6 Apr 2016 04:05:23 -0400 From: Borislav Petkov To: X86 ML Cc: LKML , stable@vger.kernel.org, Gong Chen , "H. Peter Anvin" , Ingo Molnar , linux-edac , Thomas Gleixner , Tony Luck Subject: [PATCH 3/3] x86/mce: Avoid using object after free in genpool Date: Wed, 6 Apr 2016 10:05:16 +0200 Message-Id: <1459929916-12852-4-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.7.3 In-Reply-To: <1459929916-12852-1-git-send-email-bp@alien8.de> References: <1459929916-12852-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tony Luck 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. Signed-off-by: Tony Luck Cc: Cc: Gong Chen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml Link: http://lkml.kernel.org/r/0205920@agluck-desk.sc.intel.com Signed-off-by: Borislav Petkov --- 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)); -- 2.7.3