linux/lib/fault-inject.c
Qi Zheng 3f913fc5f9 mm: fix missing handler for __GFP_NOWARN
We expect no warnings to be issued when we specify __GFP_NOWARN, but
currently in paths like alloc_pages() and kmalloc(), there are still some
warnings printed, fix it.

But for some warnings that report usage problems, we don't deal with them.
If such warnings are printed, then we should fix the usage problems. 
Such as the following case:

	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));

[zhengqi.arch@bytedance.com: v2]
 Link: https://lkml.kernel.org/r/20220511061951.1114-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20220510113809.80626-1-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-19 14:08:55 -07:00

238 lines
5.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/stacktrace.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 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;
}
EXPORT_SYMBOL_GPL(setup_fault_attr);
static void fail_dump(struct fault_attr *attr)
{
if (attr->no_warn)
return;
if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) {
printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n"
"name %pd, interval %lu, probability %lu, "
"space %d, times %d\n", attr->dname,
attr->interval, attr->probability,
atomic_read(&attr->space),
atomic_read(&attr->times));
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_task() && task->make_it_fail;
}
#define MAX_STACK_TRACE_DEPTH 32
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
static bool fail_stacktrace(struct fault_attr *attr)
{
int depth = attr->stacktrace_depth;
unsigned long entries[MAX_STACK_TRACE_DEPTH];
int n, nr_entries;
bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
if (depth == 0)
return found;
nr_entries = stack_trace_save(entries, depth, 1);
for (n = 0; n < 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 (in_task()) {
unsigned int fail_nth = READ_ONCE(current->fail_nth);
if (fail_nth) {
fail_nth--;
WRITE_ONCE(current->fail_nth, fail_nth);
if (!fail_nth)
goto fail;
return false;
}
}
/* No need to check any other properties if the probability is 0 */
if (attr->probability == 0)
return false;
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 <= prandom_u32() % 100)
return false;
if (!fail_stacktrace(attr))
return false;
fail:
fail_dump(attr);
if (atomic_read(&attr->times) != -1)
atomic_dec_not_zero(&attr->times);
return true;
}
EXPORT_SYMBOL_GPL(should_fail);
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int debugfs_ul_set(void *data, u64 val)
{
*(unsigned long *)data = val;
return 0;
}
static int debugfs_ul_get(void *data, u64 *val)
{
*val = *(unsigned long *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
static void debugfs_create_ul(const char *name, umode_t mode,
struct dentry *parent, unsigned long *value)
{
debugfs_create_file(name, mode, parent, value, &fops_ul);
}
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
static int debugfs_stacktrace_depth_set(void *data, u64 val)
{
*(unsigned long *)data =
min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
debugfs_stacktrace_depth_set, "%llu\n");
static void debugfs_create_stacktrace_depth(const char *name, umode_t mode,
struct dentry *parent,
unsigned long *value)
{
debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth);
}
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
struct dentry *fault_create_debugfs_attr(const char *name,
struct dentry *parent, struct fault_attr *attr)
{
umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
struct dentry *dir;
dir = debugfs_create_dir(name, parent);
if (IS_ERR(dir))
return dir;
debugfs_create_ul("probability", mode, dir, &attr->probability);
debugfs_create_ul("interval", mode, dir, &attr->interval);
debugfs_create_atomic_t("times", mode, dir, &attr->times);
debugfs_create_atomic_t("space", mode, dir, &attr->space);
debugfs_create_ul("verbose", mode, dir, &attr->verbose);
debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
&attr->ratelimit_state.interval);
debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
&attr->ratelimit_state.burst);
debugfs_create_bool("task-filter", mode, dir, &attr->task_filter);
#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
&attr->stacktrace_depth);
debugfs_create_ul("require-start", mode, dir, &attr->require_start);
debugfs_create_ul("require-end", mode, dir, &attr->require_end);
debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
attr->dname = dget(dir);
return dir;
}
EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */