Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753290AbdHWF7x (ORCPT ); Wed, 23 Aug 2017 01:59:53 -0400 Received: from mail-pf0-f169.google.com ([209.85.192.169]:36168 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751519AbdHWF7v (ORCPT ); Wed, 23 Aug 2017 01:59:51 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170822230043.9968-1-bart.vanassche@wdc.com> <20170822230043.9968-2-bart.vanassche@wdc.com> From: Dmitry Vyukov Date: Wed, 23 Aug 2017 07:59:30 +0200 Message-ID: Subject: Re: [PATCH v2 1/2] fault-inject: Restore support for task-independent fault injection To: Akinobu Mita Cc: Bart Van Assche , Andrew Morton , linux-block@vger.kernel.org, LKML , Michal Hocko Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4415 Lines: 97 On Wed, Aug 23, 2017 at 2:10 AM, Akinobu Mita wrote: > 2017-08-23 8:00 GMT+09:00 Bart Van Assche : >> Certain faults should be injected independent of the context >> in which these occur. Commit e41d58185f14 made it impossible to >> inject faults independent of their context. Restore support for >> task-independent fault injection by adding the attribute 'global'. > > There was a the problem reported by fail-make-request user and the > problem is introduced by the follow-up patches for systematic > fault injection. > > Please check the commit 9eeb52ae712e ("fault-inject: fix wrong > should_fail() decision in task context") and see if the problem > you reported is identical to the commit. Agree. Otherwise I don't understand this commit. We now have 2 orthogonal injection mechanisms: one global (original) and the new local. If one needs global injection, he/she just enables the global one. We don't seem to need the global flag on fault attributes. >> References: commit e41d58185f14 ("fault-inject: support systematic fault injection") >> Signed-off-by: Bart Van Assche >> Cc: Dmitry Vyukov >> Cc: Akinobu Mita >> Cc: Michal Hocko >> Cc: Andrew Morton >> --- >> include/linux/fault-inject.h | 11 +++++++++-- >> lib/fault-inject.c | 4 +++- >> 2 files changed, 12 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h >> index 728d4e0292aa..88dae2f21881 100644 >> --- a/include/linux/fault-inject.h >> +++ b/include/linux/fault-inject.h >> @@ -18,6 +18,7 @@ struct fault_attr { >> atomic_t times; >> atomic_t space; >> unsigned long verbose; >> + bool global; >> bool task_filter; >> unsigned long stacktrace_depth; >> unsigned long require_start; >> @@ -30,17 +31,23 @@ struct fault_attr { >> struct dentry *dname; >> }; >> >> -#define FAULT_ATTR_INITIALIZER { \ >> +#define __FAULT_ATTR_INITIALIZER(__global) { \ >> .interval = 1, \ >> .times = ATOMIC_INIT(1), \ >> .require_end = ULONG_MAX, \ >> + .global = (__global), \ >> .stacktrace_depth = 32, \ >> .ratelimit_state = RATELIMIT_STATE_INIT_DISABLED, \ >> .verbose = 2, \ >> .dname = NULL, \ >> } >> >> -#define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER >> +#define FAULT_ATTR_INITIALIZER __FAULT_ATTR_INITIALIZER(false) >> + >> +#define DECLARE_FAULT_ATTR(name) \ >> + struct fault_attr name = __FAULT_ATTR_INITIALIZER(false) >> +#define DECLARE_GLOBAL_FAULT_ATTR(name) \ >> + struct fault_attr name = __FAULT_ATTR_INITIALIZER(true) >> int setup_fault_attr(struct fault_attr *attr, char *str); >> bool should_fail(struct fault_attr *attr, ssize_t size); >> >> diff --git a/lib/fault-inject.c b/lib/fault-inject.c >> index 7d315fdb9f13..c8f6ef5df3c6 100644 >> --- a/lib/fault-inject.c >> +++ b/lib/fault-inject.c >> @@ -107,7 +107,7 @@ static inline bool fail_stacktrace(struct fault_attr *attr) >> >> bool should_fail(struct fault_attr *attr, ssize_t size) >> { >> - if (in_task()) { >> + if (!attr->global && in_task()) { >> unsigned int fail_nth = READ_ONCE(current->fail_nth); >> >> if (fail_nth && !WRITE_ONCE(current->fail_nth, fail_nth - 1)) >> @@ -224,6 +224,8 @@ struct dentry *fault_create_debugfs_attr(const char *name, >> if (!debugfs_create_u32("verbose_ratelimit_burst", mode, dir, >> &attr->ratelimit_state.burst)) >> goto fail; >> + if (!debugfs_create_bool("global", mode, dir, &attr->global)) >> + goto fail; >> if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter)) >> goto fail; >> >> -- >> 2.14.0 >>