ftrace: Convert graph filter to use hash tables
Use ftrace_hash instead of a static array of a fixed size. This is useful when a graph filter pattern matches to a large number of functions. Now hash lookup is done with preemption disabled to protect from the hash being changed/freed. Link: http://lkml.kernel.org/r/20170120024447.26097-3-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Namhyung Kim
Steven Rostedt (VMware)
parent
4046bf023b
commit
b9b0c831be
2 changed files with 156 additions and 94 deletions
|
|
@ -4378,7 +4378,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
|
|||
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
||||
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
|
||||
static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
|
||||
static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
|
||||
static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
|
||||
|
||||
static unsigned long save_global_trampoline;
|
||||
static unsigned long save_global_flags;
|
||||
|
|
@ -4401,18 +4401,17 @@ static void __init set_ftrace_early_graph(char *buf, int enable)
|
|||
{
|
||||
int ret;
|
||||
char *func;
|
||||
unsigned long *table = ftrace_graph_funcs;
|
||||
int *count = &ftrace_graph_count;
|
||||
struct ftrace_hash *hash;
|
||||
|
||||
if (!enable) {
|
||||
table = ftrace_graph_notrace_funcs;
|
||||
count = &ftrace_graph_notrace_count;
|
||||
}
|
||||
if (enable)
|
||||
hash = ftrace_graph_hash;
|
||||
else
|
||||
hash = ftrace_graph_notrace_hash;
|
||||
|
||||
while (buf) {
|
||||
func = strsep(&buf, ",");
|
||||
/* we allow only one expression at a time */
|
||||
ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
|
||||
ret = ftrace_graph_set_hash(hash, func);
|
||||
if (ret)
|
||||
printk(KERN_DEBUG "ftrace: function %s not "
|
||||
"traceable\n", func);
|
||||
|
|
@ -4536,15 +4535,20 @@ static const struct file_operations ftrace_notrace_fops = {
|
|||
|
||||
static DEFINE_MUTEX(graph_lock);
|
||||
|
||||
int ftrace_graph_count;
|
||||
int ftrace_graph_notrace_count;
|
||||
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
|
||||
unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
|
||||
struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
|
||||
struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
|
||||
|
||||
enum graph_filter_type {
|
||||
GRAPH_FILTER_NOTRACE = 0,
|
||||
GRAPH_FILTER_FUNCTION,
|
||||
};
|
||||
|
||||
struct ftrace_graph_data {
|
||||
unsigned long *table;
|
||||
size_t size;
|
||||
int *count;
|
||||
struct ftrace_hash *hash;
|
||||
struct ftrace_func_entry *entry;
|
||||
int idx; /* for hash table iteration */
|
||||
enum graph_filter_type type;
|
||||
struct ftrace_hash *new_hash;
|
||||
const struct seq_operations *seq_ops;
|
||||
};
|
||||
|
||||
|
|
@ -4552,10 +4556,31 @@ static void *
|
|||
__g_next(struct seq_file *m, loff_t *pos)
|
||||
{
|
||||
struct ftrace_graph_data *fgd = m->private;
|
||||
struct ftrace_func_entry *entry = fgd->entry;
|
||||
struct hlist_head *head;
|
||||
int i, idx = fgd->idx;
|
||||
|
||||
if (*pos >= *fgd->count)
|
||||
if (*pos >= fgd->hash->count)
|
||||
return NULL;
|
||||
return &fgd->table[*pos];
|
||||
|
||||
if (entry) {
|
||||
hlist_for_each_entry_continue(entry, hlist) {
|
||||
fgd->entry = entry;
|
||||
return entry;
|
||||
}
|
||||
|
||||
idx++;
|
||||
}
|
||||
|
||||
for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
|
||||
head = &fgd->hash->buckets[i];
|
||||
hlist_for_each_entry(entry, head, hlist) {
|
||||
fgd->entry = entry;
|
||||
fgd->idx = i;
|
||||
return entry;
|
||||
}
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static void *
|
||||
|
|
@ -4572,9 +4597,11 @@ static void *g_start(struct seq_file *m, loff_t *pos)
|
|||
mutex_lock(&graph_lock);
|
||||
|
||||
/* Nothing, tell g_show to print all functions are enabled */
|
||||
if (!*fgd->count && !*pos)
|
||||
if (ftrace_hash_empty(fgd->hash) && !*pos)
|
||||
return (void *)1;
|
||||
|
||||
fgd->idx = 0;
|
||||
fgd->entry = NULL;
|
||||
return __g_next(m, pos);
|
||||
}
|
||||
|
||||
|
|
@ -4585,22 +4612,22 @@ static void g_stop(struct seq_file *m, void *p)
|
|||
|
||||
static int g_show(struct seq_file *m, void *v)
|
||||
{
|
||||
unsigned long *ptr = v;
|
||||
struct ftrace_func_entry *entry = v;
|
||||
|
||||
if (!ptr)
|
||||
if (!entry)
|
||||
return 0;
|
||||
|
||||
if (ptr == (unsigned long *)1) {
|
||||
if (entry == (void *)1) {
|
||||
struct ftrace_graph_data *fgd = m->private;
|
||||
|
||||
if (fgd->table == ftrace_graph_funcs)
|
||||
if (fgd->type == GRAPH_FILTER_FUNCTION)
|
||||
seq_puts(m, "#### all functions enabled ####\n");
|
||||
else
|
||||
seq_puts(m, "#### no functions disabled ####\n");
|
||||
return 0;
|
||||
}
|
||||
|
||||
seq_printf(m, "%ps\n", (void *)*ptr);
|
||||
seq_printf(m, "%ps\n", (void *)entry->ip);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -4617,24 +4644,37 @@ __ftrace_graph_open(struct inode *inode, struct file *file,
|
|||
struct ftrace_graph_data *fgd)
|
||||
{
|
||||
int ret = 0;
|
||||
struct ftrace_hash *new_hash = NULL;
|
||||
|
||||
mutex_lock(&graph_lock);
|
||||
if ((file->f_mode & FMODE_WRITE) &&
|
||||
(file->f_flags & O_TRUNC)) {
|
||||
*fgd->count = 0;
|
||||
memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
|
||||
if (file->f_mode & FMODE_WRITE) {
|
||||
const int size_bits = FTRACE_HASH_DEFAULT_BITS;
|
||||
|
||||
if (file->f_flags & O_TRUNC)
|
||||
new_hash = alloc_ftrace_hash(size_bits);
|
||||
else
|
||||
new_hash = alloc_and_copy_ftrace_hash(size_bits,
|
||||
fgd->hash);
|
||||
if (!new_hash) {
|
||||
ret = -ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
mutex_unlock(&graph_lock);
|
||||
|
||||
if (file->f_mode & FMODE_READ) {
|
||||
ret = seq_open(file, fgd->seq_ops);
|
||||
ret = seq_open(file, &ftrace_graph_seq_ops);
|
||||
if (!ret) {
|
||||
struct seq_file *m = file->private_data;
|
||||
m->private = fgd;
|
||||
} else {
|
||||
/* Failed */
|
||||
free_ftrace_hash(new_hash);
|
||||
new_hash = NULL;
|
||||
}
|
||||
} else
|
||||
file->private_data = fgd;
|
||||
|
||||
out:
|
||||
fgd->new_hash = new_hash;
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
@ -4642,6 +4682,7 @@ static int
|
|||
ftrace_graph_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct ftrace_graph_data *fgd;
|
||||
int ret;
|
||||
|
||||
if (unlikely(ftrace_disabled))
|
||||
return -ENODEV;
|
||||
|
|
@ -4650,18 +4691,25 @@ ftrace_graph_open(struct inode *inode, struct file *file)
|
|||
if (fgd == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
fgd->table = ftrace_graph_funcs;
|
||||
fgd->size = FTRACE_GRAPH_MAX_FUNCS;
|
||||
fgd->count = &ftrace_graph_count;
|
||||
mutex_lock(&graph_lock);
|
||||
|
||||
fgd->hash = ftrace_graph_hash;
|
||||
fgd->type = GRAPH_FILTER_FUNCTION;
|
||||
fgd->seq_ops = &ftrace_graph_seq_ops;
|
||||
|
||||
return __ftrace_graph_open(inode, file, fgd);
|
||||
ret = __ftrace_graph_open(inode, file, fgd);
|
||||
if (ret < 0)
|
||||
kfree(fgd);
|
||||
|
||||
mutex_unlock(&graph_lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int
|
||||
ftrace_graph_notrace_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct ftrace_graph_data *fgd;
|
||||
int ret;
|
||||
|
||||
if (unlikely(ftrace_disabled))
|
||||
return -ENODEV;
|
||||
|
|
@ -4670,45 +4718,53 @@ ftrace_graph_notrace_open(struct inode *inode, struct file *file)
|
|||
if (fgd == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
fgd->table = ftrace_graph_notrace_funcs;
|
||||
fgd->size = FTRACE_GRAPH_MAX_FUNCS;
|
||||
fgd->count = &ftrace_graph_notrace_count;
|
||||
mutex_lock(&graph_lock);
|
||||
|
||||
fgd->hash = ftrace_graph_notrace_hash;
|
||||
fgd->type = GRAPH_FILTER_NOTRACE;
|
||||
fgd->seq_ops = &ftrace_graph_seq_ops;
|
||||
|
||||
return __ftrace_graph_open(inode, file, fgd);
|
||||
ret = __ftrace_graph_open(inode, file, fgd);
|
||||
if (ret < 0)
|
||||
kfree(fgd);
|
||||
|
||||
mutex_unlock(&graph_lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int
|
||||
ftrace_graph_release(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct ftrace_graph_data *fgd;
|
||||
|
||||
if (file->f_mode & FMODE_READ) {
|
||||
struct seq_file *m = file->private_data;
|
||||
|
||||
kfree(m->private);
|
||||
fgd = m->private;
|
||||
seq_release(inode, file);
|
||||
} else {
|
||||
kfree(file->private_data);
|
||||
fgd = file->private_data;
|
||||
}
|
||||
|
||||
kfree(fgd->new_hash);
|
||||
kfree(fgd);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
|
||||
ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
|
||||
{
|
||||
struct ftrace_glob func_g;
|
||||
struct dyn_ftrace *rec;
|
||||
struct ftrace_page *pg;
|
||||
struct ftrace_func_entry *entry;
|
||||
int fail = 1;
|
||||
int not;
|
||||
bool exists;
|
||||
int i;
|
||||
|
||||
/* decode regex */
|
||||
func_g.type = filter_parse_regex(buffer, strlen(buffer),
|
||||
&func_g.search, ¬);
|
||||
if (!not && *idx >= size)
|
||||
return -EBUSY;
|
||||
|
||||
func_g.len = strlen(func_g.search);
|
||||
|
||||
|
|
@ -4725,26 +4781,18 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
|
|||
continue;
|
||||
|
||||
if (ftrace_match_record(rec, &func_g, NULL, 0)) {
|
||||
/* if it is in the array */
|
||||
exists = false;
|
||||
for (i = 0; i < *idx; i++) {
|
||||
if (array[i] == rec->ip) {
|
||||
exists = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
entry = ftrace_lookup_ip(hash, rec->ip);
|
||||
|
||||
if (!not) {
|
||||
fail = 0;
|
||||
if (!exists) {
|
||||
array[(*idx)++] = rec->ip;
|
||||
if (*idx >= size)
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (entry)
|
||||
continue;
|
||||
if (add_hash_entry(hash, rec->ip) < 0)
|
||||
goto out;
|
||||
} else {
|
||||
if (exists) {
|
||||
array[i] = array[--(*idx)];
|
||||
array[*idx] = 0;
|
||||
if (entry) {
|
||||
free_hash_entry(hash, entry);
|
||||
fail = 0;
|
||||
}
|
||||
}
|
||||
|
|
@ -4766,6 +4814,7 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
|
|||
struct trace_parser parser;
|
||||
ssize_t read, ret = 0;
|
||||
struct ftrace_graph_data *fgd = file->private_data;
|
||||
struct ftrace_hash *old_hash, *new_hash;
|
||||
|
||||
if (!cnt)
|
||||
return 0;
|
||||
|
|
@ -4781,10 +4830,25 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
|
|||
mutex_lock(&graph_lock);
|
||||
|
||||
/* we allow only one expression at a time */
|
||||
ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
|
||||
parser.buffer);
|
||||
ret = ftrace_graph_set_hash(fgd->new_hash,
|
||||
parser.buffer);
|
||||
|
||||
old_hash = fgd->hash;
|
||||
new_hash = __ftrace_hash_move(fgd->new_hash);
|
||||
if (!new_hash)
|
||||
ret = -ENOMEM;
|
||||
|
||||
if (fgd->type == GRAPH_FILTER_FUNCTION)
|
||||
rcu_assign_pointer(ftrace_graph_hash, new_hash);
|
||||
else
|
||||
rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
|
||||
|
||||
mutex_unlock(&graph_lock);
|
||||
|
||||
/* Wait till all users are no longer using the old hash */
|
||||
synchronize_sched();
|
||||
|
||||
free_ftrace_hash(old_hash);
|
||||
}
|
||||
|
||||
if (!ret)
|
||||
|
|
|
|||
|
|
@ -803,51 +803,49 @@ extern void __trace_graph_return(struct trace_array *tr,
|
|||
unsigned long flags, int pc);
|
||||
|
||||
#ifdef CONFIG_DYNAMIC_FTRACE
|
||||
/* TODO: make this variable */
|
||||
#define FTRACE_GRAPH_MAX_FUNCS 32
|
||||
extern int ftrace_graph_count;
|
||||
extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
|
||||
extern int ftrace_graph_notrace_count;
|
||||
extern unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS];
|
||||
extern struct ftrace_hash *ftrace_graph_hash;
|
||||
extern struct ftrace_hash *ftrace_graph_notrace_hash;
|
||||
|
||||
static inline int ftrace_graph_addr(unsigned long addr)
|
||||
{
|
||||
int i;
|
||||
int ret = 0;
|
||||
|
||||
if (!ftrace_graph_count)
|
||||
return 1;
|
||||
preempt_disable_notrace();
|
||||
|
||||
for (i = 0; i < ftrace_graph_count; i++) {
|
||||
if (addr == ftrace_graph_funcs[i]) {
|
||||
/*
|
||||
* If no irqs are to be traced, but a set_graph_function
|
||||
* is set, and called by an interrupt handler, we still
|
||||
* want to trace it.
|
||||
*/
|
||||
if (in_irq())
|
||||
trace_recursion_set(TRACE_IRQ_BIT);
|
||||
else
|
||||
trace_recursion_clear(TRACE_IRQ_BIT);
|
||||
return 1;
|
||||
}
|
||||
if (ftrace_hash_empty(ftrace_graph_hash)) {
|
||||
ret = 1;
|
||||
goto out;
|
||||
}
|
||||
|
||||
return 0;
|
||||
if (ftrace_lookup_ip(ftrace_graph_hash, addr)) {
|
||||
/*
|
||||
* If no irqs are to be traced, but a set_graph_function
|
||||
* is set, and called by an interrupt handler, we still
|
||||
* want to trace it.
|
||||
*/
|
||||
if (in_irq())
|
||||
trace_recursion_set(TRACE_IRQ_BIT);
|
||||
else
|
||||
trace_recursion_clear(TRACE_IRQ_BIT);
|
||||
ret = 1;
|
||||
}
|
||||
|
||||
out:
|
||||
preempt_enable_notrace();
|
||||
return ret;
|
||||
}
|
||||
|
||||
static inline int ftrace_graph_notrace_addr(unsigned long addr)
|
||||
{
|
||||
int i;
|
||||
int ret = 0;
|
||||
|
||||
if (!ftrace_graph_notrace_count)
|
||||
return 0;
|
||||
preempt_disable_notrace();
|
||||
|
||||
for (i = 0; i < ftrace_graph_notrace_count; i++) {
|
||||
if (addr == ftrace_graph_notrace_funcs[i])
|
||||
return 1;
|
||||
}
|
||||
if (ftrace_lookup_ip(ftrace_graph_notrace_hash, addr))
|
||||
ret = 1;
|
||||
|
||||
return 0;
|
||||
preempt_enable_notrace();
|
||||
return ret;
|
||||
}
|
||||
#else
|
||||
static inline int ftrace_graph_addr(unsigned long addr)
|
||||
|
|
|
|||
Loading…
Reference in a new issue