On Wed, Aug 23, 2017 at 2:10 AM, Akinobu Mita <akinobu.mita@xxxxxxxxx> wrote:
> 2017-08-23 8:00 GMT+09:00 Bart Van Assche <bart.vanassche@xxxxxxx>:
>> 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 <bart.vanassche@xxxxxxx>
>> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
>> Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> ---
>> 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
>>
