linux-kernel - [PATCH 1/2] fault-inject: Restore support for task-independent fault injection

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Date:   Tue, 22 Aug 2017 09:52:35 -0700
From:   Bart Van Assche <bart.vanassche@....com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bart Van Assche <bart.vanassche@....com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Akinobu Mita <akinobu.mita@...il.com>,
        Michal Hocko <mhocko@...nel.org>
Subject: [PATCH 1/2] fault-inject: Restore support for task-independent fault injection

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'.

References: commit e41d58185f14 ("fault-inject: support systematic fault injection")
Signed-off-by: Bart Van Assche <bart.vanassche@....com>
Cc: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Akinobu Mita <akinobu.mita@...il.com>
Cc: Michal Hocko <mhocko@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
---
 include/linux/fault-inject.h | 9 +++++++--
 lib/fault-inject.c           | 4 +++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index 728d4e0292aa..8851646d2698 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 +31,21 @@ 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 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