3.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
commit 33b7f99cf003ca6c1d31c42b50e1100ad71aaec0 upstream.
Currently the top level debug file system function tracer shares its
ftrace_ops with the function graph tracer. This was thought to be fine
because the tracers are not used together, as one can only enable
function or function_graph tracer in the current_tracer file.
But that assumption proved to be incorrect. The function profiler
can use the function graph tracer when function tracing is enabled.
Since all function graph users uses the function tracing ftrace_ops
this causes a conflict and when a user enables both function profiling
as well as the function tracer it will crash ftrace and disable it.
The quick solution so far is to move them as separate ftrace_ops like
it was earlier. The problem though is to synchronize the functions that
are traced because both function and function_graph tracer are limited
by the selections made in the set_ftrace_filter and set_ftrace_notrace
files.
To handle this, a new structure is made called ftrace_ops_hash. This
structure will now hold the filter_hash and notrace_hash, and the
ftrace_ops will point to this structure. That will allow two ftrace_ops
to share the same hashes.
Since most ftrace_ops do not share the hashes, and to keep allocation
simple, the ftrace_ops structure will include both a pointer to the
ftrace_ops_hash called func_hash, as well as the structure itself,
called local_hash. When the ops are registered, the func_hash pointer
will be initialized to point to the local_hash within the ftrace_ops
structure. Some of the ftrace internal ftrace_ops will be initialized
statically. This will allow for the function and function_graph tracer
to have separate ops but still share the same hash tables that determine
what functions they trace.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/ftrace.h | 13 +++++-
kernel/trace/ftrace.c | 98 +++++++++++++++++++++++++------------------------
2 files changed, 62 insertions(+), 49 deletions(-)
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -103,6 +103,15 @@ enum {
FTRACE_OPS_FL_DELETED = 1 << 8,
};
+#ifdef CONFIG_DYNAMIC_FTRACE
+/* The hash used to know what functions callbacks trace */
+struct ftrace_ops_hash {
+ struct ftrace_hash *notrace_hash;
+ struct ftrace_hash *filter_hash;
+ struct mutex regex_lock;
+};
+#endif
+
/*
* Note, ftrace_ops can be referenced outside of RCU protection.
* (Although, for perf, the control ops prevent that). If ftrace_ops is
@@ -121,8 +130,8 @@ struct ftrace_ops {
int __percpu *disabled;
void *private;
#ifdef CONFIG_DYNAMIC_FTRACE
- struct ftrace_hash *notrace_hash;
- struct ftrace_hash *filter_hash;
+ struct ftrace_ops_hash local_hash;
+ struct ftrace_ops_hash *func_hash;
struct mutex regex_lock;
#endif
};
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -65,15 +65,17 @@
#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
#ifdef CONFIG_DYNAMIC_FTRACE
-#define INIT_REGEX_LOCK(opsname) \
- .regex_lock = __MUTEX_INITIALIZER(opsname.regex_lock),
+#define INIT_OPS_HASH(opsname) \
+ .func_hash = &opsname.local_hash, \
+ .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
#else
-#define INIT_REGEX_LOCK(opsname)
+#define INIT_OPS_HASH(opsname)
#endif
static struct ftrace_ops ftrace_list_end __read_mostly = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
+ INIT_OPS_HASH(ftrace_list_end)
};
/* ftrace_enabled is a method to turn ftrace on or off */
@@ -143,7 +145,8 @@ static inline void ftrace_ops_init(struc
{
#ifdef CONFIG_DYNAMIC_FTRACE
if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
- mutex_init(&ops->regex_lock);
+ mutex_init(&ops->local_hash.regex_lock);
+ ops->func_hash = &ops->local_hash;
ops->flags |= FTRACE_OPS_FL_INITIALIZED;
}
#endif
@@ -902,7 +905,7 @@ static void unregister_ftrace_profiler(v
static struct ftrace_ops ftrace_profile_ops __read_mostly = {
.func = function_profile_call,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
- INIT_REGEX_LOCK(ftrace_profile_ops)
+ INIT_OPS_HASH(ftrace_profile_ops)
};
static int register_ftrace_profiler(void)
@@ -1082,11 +1085,12 @@ static const struct ftrace_hash empty_ha
#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
static struct ftrace_ops global_ops = {
- .func = ftrace_stub,
- .notrace_hash = EMPTY_HASH,
- .filter_hash = EMPTY_HASH,
- .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
- INIT_REGEX_LOCK(global_ops)
+ .func = ftrace_stub,
+ .local_hash.notrace_hash = EMPTY_HASH,
+ .local_hash.filter_hash = EMPTY_HASH,
+ INIT_OPS_HASH(global_ops)
+ .flags = FTRACE_OPS_FL_RECURSION_SAFE |
+ FTRACE_OPS_FL_INITIALIZED,
};
struct ftrace_page {
@@ -1227,8 +1231,8 @@ static void free_ftrace_hash_rcu(struct
void ftrace_free_filter(struct ftrace_ops *ops)
{
ftrace_ops_init(ops);
- free_ftrace_hash(ops->filter_hash);
- free_ftrace_hash(ops->notrace_hash);
+ free_ftrace_hash(ops->func_hash->filter_hash);
+ free_ftrace_hash(ops->func_hash->notrace_hash);
}
static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
@@ -1394,8 +1398,8 @@ ftrace_ops_test(struct ftrace_ops *ops,
return 0;
#endif
- filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
- notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
+ filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
+ notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
if ((ftrace_hash_empty(filter_hash) ||
ftrace_lookup_ip(filter_hash, ip)) &&
@@ -1519,14 +1523,14 @@ static void __ftrace_hash_rec_update(str
* gets inversed.
*/
if (filter_hash) {
- hash = ops->filter_hash;
- other_hash = ops->notrace_hash;
+ hash = ops->func_hash->filter_hash;
+ other_hash = ops->func_hash->notrace_hash;
if (ftrace_hash_empty(hash))
all = 1;
} else {
inc = !inc;
- hash = ops->notrace_hash;
- other_hash = ops->filter_hash;
+ hash = ops->func_hash->notrace_hash;
+ other_hash = ops->func_hash->filter_hash;
/*
* If the notrace hash has no items,
* then there's nothing to do.
@@ -2196,8 +2200,8 @@ static inline int ops_traces_mod(struct
* Filter_hash being empty will default to trace module.
* But notrace hash requires a test of individual module functions.
*/
- return ftrace_hash_empty(ops->filter_hash) &&
- ftrace_hash_empty(ops->notrace_hash);
+ return ftrace_hash_empty(ops->func_hash->filter_hash) &&
+ ftrace_hash_empty(ops->func_hash->notrace_hash);
}
/*
@@ -2219,12 +2223,12 @@ ops_references_rec(struct ftrace_ops *op
return 0;
/* The function must be in the filter */
- if (!ftrace_hash_empty(ops->filter_hash) &&
- !ftrace_lookup_ip(ops->filter_hash, rec->ip))
+ if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
+ !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
return 0;
/* If in notrace hash, we ignore it too */
- if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
+ if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
return 0;
return 1;
@@ -2544,10 +2548,10 @@ t_next(struct seq_file *m, void *v, loff
} else {
rec = &iter->pg->records[iter->idx++];
if (((iter->flags & FTRACE_ITER_FILTER) &&
- !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
+ !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
((iter->flags & FTRACE_ITER_NOTRACE) &&
- !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
+ !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
((iter->flags & FTRACE_ITER_ENABLED) &&
!(rec->flags & FTRACE_FL_ENABLED))) {
@@ -2596,7 +2600,7 @@ static void *t_start(struct seq_file *m,
* functions are enabled.
*/
if (iter->flags & FTRACE_ITER_FILTER &&
- ftrace_hash_empty(ops->filter_hash)) {
+ ftrace_hash_empty(ops->func_hash->filter_hash)) {
if (*pos > 0)
return t_hash_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
@@ -2750,12 +2754,12 @@ ftrace_regex_open(struct ftrace_ops *ops
iter->ops = ops;
iter->flags = flag;
- mutex_lock(&ops->regex_lock);
+ mutex_lock(&ops->func_hash->regex_lock);
if (flag & FTRACE_ITER_NOTRACE)
- hash = ops->notrace_hash;
+ hash = ops->func_hash->notrace_hash;
else
- hash = ops->filter_hash;
+ hash = ops->func_hash->filter_hash;
if (file->f_mode & FMODE_WRITE) {
iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
@@ -2788,7 +2792,7 @@ ftrace_regex_open(struct ftrace_ops *ops
file->private_data = iter;
out_unlock:
- mutex_unlock(&ops->regex_lock);
+ mutex_unlock(&ops->func_hash->regex_lock);
return ret;
}
@@ -3026,7 +3030,7 @@ static struct ftrace_ops trace_probe_ops
{
.func = function_trace_probe_call,
.flags = FTRACE_OPS_FL_INITIALIZED,
- INIT_REGEX_LOCK(trace_probe_ops)
+ INIT_OPS_HASH(trace_probe_ops)
};
static int ftrace_probe_registered;
@@ -3089,7 +3093,7 @@ register_ftrace_function_probe(char *glo
void *data)
{
struct ftrace_func_probe *entry;
- struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
+ struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
struct ftrace_hash *hash;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
@@ -3106,7 +3110,7 @@ register_ftrace_function_probe(char *glo
if (WARN_ON(not))
return -EINVAL;
- mutex_lock(&trace_probe_ops.regex_lock);
+ mutex_lock(&trace_probe_ops.func_hash->regex_lock);
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash) {
@@ -3175,7 +3179,7 @@ register_ftrace_function_probe(char *glo
out_unlock:
mutex_unlock(&ftrace_lock);
out:
- mutex_unlock(&trace_probe_ops.regex_lock);
+ mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
free_ftrace_hash(hash);
return count;
@@ -3193,7 +3197,7 @@ __unregister_ftrace_function_probe(char
struct ftrace_func_entry *rec_entry;
struct ftrace_func_probe *entry;
struct ftrace_func_probe *p;
- struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
+ struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
struct list_head free_list;
struct ftrace_hash *hash;
struct hlist_node *tmp;
@@ -3215,7 +3219,7 @@ __unregister_ftrace_function_probe(char
return;
}
- mutex_lock(&trace_probe_ops.regex_lock);
+ mutex_lock(&trace_probe_ops.func_hash->regex_lock);
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash)
@@ -3268,7 +3272,7 @@ __unregister_ftrace_function_probe(char
mutex_unlock(&ftrace_lock);
out_unlock:
- mutex_unlock(&trace_probe_ops.regex_lock);
+ mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
free_ftrace_hash(hash);
}
@@ -3464,12 +3468,12 @@ ftrace_set_hash(struct ftrace_ops *ops,
if (unlikely(ftrace_disabled))
return -ENODEV;
- mutex_lock(&ops->regex_lock);
+ mutex_lock(&ops->func_hash->regex_lock);
if (enable)
- orig_hash = &ops->filter_hash;
+ orig_hash = &ops->func_hash->filter_hash;
else
- orig_hash = &ops->notrace_hash;
+ orig_hash = &ops->func_hash->notrace_hash;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash) {
@@ -3497,7 +3501,7 @@ ftrace_set_hash(struct ftrace_ops *ops,
mutex_unlock(&ftrace_lock);
out_regex_unlock:
- mutex_unlock(&ops->regex_lock);
+ mutex_unlock(&ops->func_hash->regex_lock);
free_ftrace_hash(hash);
return ret;
@@ -3704,15 +3708,15 @@ int ftrace_regex_release(struct inode *i
trace_parser_put(parser);
- mutex_lock(&iter->ops->regex_lock);
+ mutex_lock(&iter->ops->func_hash->regex_lock);
if (file->f_mode & FMODE_WRITE) {
filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
if (filter_hash)
- orig_hash = &iter->ops->filter_hash;
+ orig_hash = &iter->ops->func_hash->filter_hash;
else
- orig_hash = &iter->ops->notrace_hash;
+ orig_hash = &iter->ops->func_hash->notrace_hash;
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move(iter->ops, filter_hash,
@@ -3723,7 +3727,7 @@ int ftrace_regex_release(struct inode *i
mutex_unlock(&ftrace_lock);
}
- mutex_unlock(&iter->ops->regex_lock);
+ mutex_unlock(&iter->ops->func_hash->regex_lock);
free_ftrace_hash(iter->hash);
kfree(iter);
@@ -4335,7 +4339,7 @@ void __init ftrace_init(void)
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
- INIT_REGEX_LOCK(global_ops)
+ INIT_OPS_HASH(global_ops)
};
static int __init ftrace_nodyn_init(void)
@@ -4437,7 +4441,7 @@ ftrace_ops_control_func(unsigned long ip
static struct ftrace_ops control_ops = {
.func = ftrace_ops_control_func,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
- INIT_REGEX_LOCK(control_ops)
+ INIT_OPS_HASH(control_ops)
};
static inline void
--
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