linux-stable/lib/fault-inject.c
Akinobu Mita 1df49008f4 [PATCH] fault injection: split up stacktrace filter Kconfig option
There is no prompt for CONFIG_STACKTRACE, so FAULT_INJECTION cannot be
selected without LOCKDEP enabled.  (found by Paolo 'Blaisorblade'
Giarrusso)

In order to fix such broken Kconfig dependency, this patch splits up the
stacktrace filter support for fault injection by new Kconfig option, which
enables to use fault injection on the architecture which doesn't have
general stacktrace support.

Cc: "Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-20 17:10:14 -08:00

307 lines
7.6 KiB
C

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/stat.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/unwind.h>
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
#include <linux/fault-inject.h>
/*
* setup_fault_attr() is a helper function for various __setup handlers, so it
* returns 0 on error, because that is what __setup handlers do.
*/
int __init setup_fault_attr(struct fault_attr *attr, char *str)
{
unsigned long probability;
unsigned long interval;
int times;
int space;
/* "<interval>,<probability>,<space>,<times>" */
if (sscanf(str, "%lu,%lu,%d,%d",
&interval, &probability, &space, &times) < 4) {
printk(KERN_WARNING
"FAULT_INJECTION: failed to parse arguments\n");
return 0;
}
attr->probability = probability;
attr->interval = interval;
atomic_set(&attr->times, times);
atomic_set(&attr->space, space);
return 1;
}
static void fail_dump(struct fault_attr *attr)
{
if (attr->verbose > 0)
printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
if (attr->verbose > 1)
dump_stack();
}
#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
static bool fail_task(struct fault_attr *attr, struct task_struct *task)
{
return !in_interrupt() && task->make_it_fail;
}
#define MAX_STACK_TRACE_DEPTH 32
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
static bool fail_stacktrace(struct fault_attr *attr)
{
struct stack_trace trace;
int depth = attr->stacktrace_depth;
unsigned long entries[MAX_STACK_TRACE_DEPTH];
int n;
bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
if (depth == 0)
return found;
trace.nr_entries = 0;
trace.entries = entries;
trace.max_entries = depth;
trace.skip = 1;
trace.all_contexts = 0;
save_stack_trace(&trace, NULL);
for (n = 0; n < trace.nr_entries; n++) {
if (attr->reject_start <= entries[n] &&
entries[n] < attr->reject_end)
return false;
if (attr->require_start <= entries[n] &&
entries[n] < attr->require_end)
found = true;
}
return found;
}
#else
static inline bool fail_stacktrace(struct fault_attr *attr)
{
return true;
}
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
/*
* This code is stolen from failmalloc-1.0
* http://www.nongnu.org/failmalloc/
*/
bool should_fail(struct fault_attr *attr, ssize_t size)
{
if (attr->task_filter && !fail_task(attr, current))
return false;
if (atomic_read(&attr->times) == 0)
return false;
if (atomic_read(&attr->space) > size) {
atomic_sub(size, &attr->space);
return false;
}
if (attr->interval > 1) {
attr->count++;
if (attr->count % attr->interval)
return false;
}
if (attr->probability <= random32() % 100)
return false;
if (!fail_stacktrace(attr))
return false;
fail_dump(attr);
if (atomic_read(&attr->times) != -1)
atomic_dec_not_zero(&attr->times);
return true;
}
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static void debugfs_ul_set(void *data, u64 val)
{
*(unsigned long *)data = val;
}
static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
{
*(unsigned long *)data =
val < MAX_STACK_TRACE_DEPTH ?
val : MAX_STACK_TRACE_DEPTH;
}
static u64 debugfs_ul_get(void *data)
{
return *(unsigned long *)data;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
struct dentry *parent, unsigned long *value)
{
return debugfs_create_file(name, mode, parent, value, &fops_ul);
}
DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
const char *name, mode_t mode,
struct dentry *parent, unsigned long *value)
{
return debugfs_create_file(name, mode, parent, value,
&fops_ul_MAX_STACK_TRACE_DEPTH);
}
static void debugfs_atomic_t_set(void *data, u64 val)
{
atomic_set((atomic_t *)data, val);
}
static u64 debugfs_atomic_t_get(void *data)
{
return atomic_read((atomic_t *)data);
}
DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
debugfs_atomic_t_set, "%lld\n");
static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
struct dentry *parent, atomic_t *value)
{
return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
}
void cleanup_fault_attr_dentries(struct fault_attr *attr)
{
debugfs_remove(attr->dentries.probability_file);
attr->dentries.probability_file = NULL;
debugfs_remove(attr->dentries.interval_file);
attr->dentries.interval_file = NULL;
debugfs_remove(attr->dentries.times_file);
attr->dentries.times_file = NULL;
debugfs_remove(attr->dentries.space_file);
attr->dentries.space_file = NULL;
debugfs_remove(attr->dentries.verbose_file);
attr->dentries.verbose_file = NULL;
debugfs_remove(attr->dentries.task_filter_file);
attr->dentries.task_filter_file = NULL;
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
debugfs_remove(attr->dentries.stacktrace_depth_file);
attr->dentries.stacktrace_depth_file = NULL;
debugfs_remove(attr->dentries.require_start_file);
attr->dentries.require_start_file = NULL;
debugfs_remove(attr->dentries.require_end_file);
attr->dentries.require_end_file = NULL;
debugfs_remove(attr->dentries.reject_start_file);
attr->dentries.reject_start_file = NULL;
debugfs_remove(attr->dentries.reject_end_file);
attr->dentries.reject_end_file = NULL;
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
if (attr->dentries.dir)
WARN_ON(!simple_empty(attr->dentries.dir));
debugfs_remove(attr->dentries.dir);
attr->dentries.dir = NULL;
}
int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
{
mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
struct dentry *dir;
memset(&attr->dentries, 0, sizeof(attr->dentries));
dir = debugfs_create_dir(name, NULL);
if (!dir)
goto fail;
attr->dentries.dir = dir;
attr->dentries.probability_file =
debugfs_create_ul("probability", mode, dir, &attr->probability);
attr->dentries.interval_file =
debugfs_create_ul("interval", mode, dir, &attr->interval);
attr->dentries.times_file =
debugfs_create_atomic_t("times", mode, dir, &attr->times);
attr->dentries.space_file =
debugfs_create_atomic_t("space", mode, dir, &attr->space);
attr->dentries.verbose_file =
debugfs_create_ul("verbose", mode, dir, &attr->verbose);
attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
mode, dir, &attr->task_filter);
if (!attr->dentries.probability_file || !attr->dentries.interval_file ||
!attr->dentries.times_file || !attr->dentries.space_file ||
!attr->dentries.verbose_file || !attr->dentries.task_filter_file)
goto fail;
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
attr->dentries.stacktrace_depth_file =
debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
"stacktrace-depth", mode, dir, &attr->stacktrace_depth);
attr->dentries.require_start_file =
debugfs_create_ul("require-start", mode, dir, &attr->require_start);
attr->dentries.require_end_file =
debugfs_create_ul("require-end", mode, dir, &attr->require_end);
attr->dentries.reject_start_file =
debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
attr->dentries.reject_end_file =
debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
if (!attr->dentries.stacktrace_depth_file ||
!attr->dentries.require_start_file ||
!attr->dentries.require_end_file ||
!attr->dentries.reject_start_file ||
!attr->dentries.reject_end_file)
goto fail;
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
return 0;
fail:
cleanup_fault_attr_dentries(attr);
return -ENOMEM;
}
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */