Hello Andrew,
A recent change in the fault injection code introduced an undesired change
in the behavior of the I/O timeout failure injection code. This series
restores the original behavior. Please consider these patches for kernel
v4.14.
Thanks,
Bart.
Bart Van Assche (2):
fault-inject: Restore support for task-independent fault injection
block: Make I/O timeout failure injection support again
task-independent
block/blk-timeout.c | 2 +-
include/linux/fault-inject.h | 9 +++++++--
lib/fault-inject.c | 4 +++-
3 files changed, 11 insertions(+), 4 deletions(-)
--
2.14.0
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 <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrew Morton <[email protected]>
---
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
Commit e41d58185f14 made all faults that are triggered from task
context, including I/O timeouts, dependent on the failure
injection settings for that task. Make it again possible to inject
I/O timeout failures independent of task context. An example for a
fault injection for which this patch makes a difference (from a VM
booted with the 'threadirqs' command line parameter):
FAULT_INJECTION: forcing a failure. name fail_io_timeout, interval 1, probability 100, space 0, times 1
CPU: 6 PID: 1253 Comm: irq/36-skd0-msi Not tainted 4.13.0-rc2-dbg+ #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc26 04/01/2014
Call Trace:
dump_stack+0x8e/0xcd
should_fail+0x154/0x160
blk_should_fake_timeout+0x27/0x30
blk_mq_complete_request+0x11/0x30
skd_end_request+0x32/0xc0 [skd]
skd_isr_completion_posted.isra.30+0x14a/0x400 [skd]
skd_comp_q+0x40/0xb0 [skd]
irq_forced_thread_fn+0x2a/0x70
irq_thread+0x144/0x1a0
kthread+0x125/0x140
ret_from_fork+0x2a/0x40
Fixes: commit e41d58185f14 ("fault-inject: support systematic fault injection")
Signed-off-by: Bart Van Assche <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrew Morton <[email protected]>
---
block/blk-timeout.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 17ec83bb0900..2e92b20b125f 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -11,7 +11,7 @@
#ifdef CONFIG_FAIL_IO_TIMEOUT
-static DECLARE_FAULT_ATTR(fail_io_timeout);
+static DECLARE_GLOBAL_FAULT_ATTR(fail_io_timeout);
static int __init setup_fail_io_timeout(char *str)
{
--
2.14.0