From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757754AbcHCPKV (ORCPT ); Wed, 3 Aug 2016 11:10:21 -0400 Received: from userp1050.oracle.com ([156.151.31.82]:51446 "EHLO userp1050.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756048AbcHCPKI (ORCPT ); Wed, 3 Aug 2016 11:10:08 -0400 From: Vegard Nossum To: Akinobu Mita , Peter Zijlstra , Ingo Molnar Cc: linux-kernel@vger.kernel.org, Vegard Nossum Subject: [PATCH 08/10] fault injection: down_{read,write}_trylock() fault injection Date: Wed, 3 Aug 2016 17:05:53 +0200 Message-Id: <1470236755-29844-8-git-send-email-vegard.nossum@oracle.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1470236755-29844-1-git-send-email-vegard.nossum@oracle.com> References: <1470236755-29844-1-git-send-email-vegard.nossum@oracle.com> X-Source-IP: userp1040.oracle.com [156.151.31.81] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Vegard Nossum --- kernel/locking/rwsem.c | 35 +++++++++++++++++++++++++++++++++-- lib/Kconfig.debug | 6 ++++++ 2 files changed, 39 insertions(+), 2 deletions(-) diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 45ba475..e52ffd3 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -4,6 +4,7 @@ * Derived from asm-i386/semaphore.h */ +#include #include #include #include @@ -13,6 +14,28 @@ #include "rwsem.h" +#ifdef CONFIG_FAIL_RW_SEMAPHORE +DECLARE_FAULT_ATTR(fail_rwsem); + +static int __init fail_rwsem_debugfs(void) +{ + struct dentry *dir = fault_create_debugfs_attr("fail_rwsem", + NULL, &fail_rwsem); + return PTR_ERR_OR_ZERO(dir); +} +late_initcall(fail_rwsem_debugfs); + +static inline bool should_fail_rwsem(struct rw_semaphore *sem) +{ + return should_fail(&fail_rwsem, 1); +} +#else +static inline bool should_fail_rwsem(struct rw_semaphore *sem) +{ + return false; +} +#endif + /* * lock for reading */ @@ -32,8 +55,12 @@ EXPORT_SYMBOL(down_read); */ int down_read_trylock(struct rw_semaphore *sem) { - int ret = __down_read_trylock(sem); + int ret; + + if (should_fail_rwsem(sem)) + return 0; + ret = __down_read_trylock(sem); if (ret == 1) { rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); rwsem_set_reader_owned(sem); @@ -81,8 +108,12 @@ EXPORT_SYMBOL(down_write_killable); */ int down_write_trylock(struct rw_semaphore *sem) { - int ret = __down_write_trylock(sem); + int ret; + + if (should_fail_rwsem(sem)) + return 0; + ret = __down_write_trylock(sem); if (ret == 1) { rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_); rwsem_set_owner(sem); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 5473759..a69289a 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1675,6 +1675,12 @@ config FAIL_SEMAPHORE help Provide fault-injection capability for down_trylock(). +config FAIL_RW_SEMAPHORE + bool "Fault-injection capability for RW semaphores" + depends on FAULT_INJECTION + help + Provide fault-injection capability for down_{read,write}_trylock(). + config FAULT_INJECTION_DEBUG_FS bool "Debugfs entries for fault-injection capabilities" depends on FAULT_INJECTION && SYSFS && DEBUG_FS -- 1.9.1