From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752784AbdBTLGi (ORCPT ); Mon, 20 Feb 2017 06:06:38 -0500 Received: from mga02.intel.com ([134.134.136.20]:57934 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751436AbdBTLGg (ORCPT ); Mon, 20 Feb 2017 06:06:36 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,186,1484035200"; d="scan'208";a="826325766" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, x86@kernel.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, hpa@zytor.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 2/4] x86: convert threshold_bank.cpus from atomic_t to refcount_t Date: Mon, 20 Feb 2017 13:06:19 +0200 Message-Id: <1487588781-15123-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487588781-15123-1-git-send-email-elena.reshetova@intel.com> References: <1487588781-15123-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- arch/x86/include/asm/amd_nb.h | 3 ++- arch/x86/kernel/cpu/mcheck/mce_amd.c | 6 +++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h index 00c88a0..da181ad 100644 --- a/arch/x86/include/asm/amd_nb.h +++ b/arch/x86/include/asm/amd_nb.h @@ -3,6 +3,7 @@ #include #include +#include struct amd_nb_bus_dev_range { u8 bus; @@ -55,7 +56,7 @@ struct threshold_bank { struct threshold_block *blocks; /* initialized to the number of CPUs on the node sharing this bank */ - atomic_t cpus; + refcount_t cpus; }; struct amd_northbridge { diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index 524cc57..cfe0838 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -1202,7 +1202,7 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank) goto out; per_cpu(threshold_banks, cpu)[bank] = b; - atomic_inc(&b->cpus); + refcount_inc(&b->cpus); err = __threshold_add_blocks(b); @@ -1225,7 +1225,7 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank) per_cpu(threshold_banks, cpu)[bank] = b; if (is_shared_bank(bank)) { - atomic_set(&b->cpus, 1); + refcount_set(&b->cpus, 1); /* nb is already initialized, see above */ if (nb) { @@ -1289,7 +1289,7 @@ static void threshold_remove_bank(unsigned int cpu, int bank) goto free_out; if (is_shared_bank(bank)) { - if (!atomic_dec_and_test(&b->cpus)) { + if (!refcount_dec_and_test(&b->cpus)) { __threshold_remove_blocks(b); per_cpu(threshold_banks, cpu)[bank] = NULL; return; -- 2.7.4