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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-06-26 11:47:31 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-06-26 11:53:04 -0400
commit8c08f0d5c6fb10ff93ffb1cbf416f4f1c3a52a80 (patch)
treed4d025db4b5ec05a0e2d553c028ea23694f7e777 /kernel/trace
parentftrace: Implement cached modules tracing on module load (diff)
downloadwireguard-linux-8c08f0d5c6fb10ff93ffb1cbf416f4f1c3a52a80.tar.xz
wireguard-linux-8c08f0d5c6fb10ff93ffb1cbf416f4f1c3a52a80.zip
ftrace: Have cached module filters be an active filter
When a module filter is added to set_ftrace_filter, if the module is not loaded, it is cached. This should be considered an active filter, and function tracing should be filtered by this. That is, if a cached module filter is the only filter set, then no function tracing should be happening, as all the functions available will be filtered out. This makes sense, as the reason to add a cached module filter, is to trace the module when you load it. There shouldn't be any other tracing happening until then. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c20
-rw-r--r--kernel/trace/trace.h7
2 files changed, 21 insertions, 6 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f1ccf8be9df7..914539e3e301 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1410,6 +1410,9 @@ alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
if (!new_hash)
return NULL;
+ if (hash)
+ new_hash->flags = hash->flags;
+
/* Empty hash? */
if (ftrace_hash_empty(hash))
return new_hash;
@@ -1454,7 +1457,7 @@ __ftrace_hash_move(struct ftrace_hash *src)
/*
* If the new source is empty, just return the empty_hash.
*/
- if (!src->count)
+ if (ftrace_hash_empty(src))
return EMPTY_HASH;
/*
@@ -1471,6 +1474,8 @@ __ftrace_hash_move(struct ftrace_hash *src)
if (!new_hash)
return NULL;
+ new_hash->flags = src->flags;
+
size = 1 << src->size_bits;
for (i = 0; i < size; i++) {
hhd = &src->buckets[i];
@@ -1701,7 +1706,7 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
struct dyn_ftrace *rec;
bool update = false;
int count = 0;
- int all = 0;
+ int all = false;
/* Only update if the ops has been registered */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
@@ -1722,7 +1727,7 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
hash = ops->func_hash->filter_hash;
other_hash = ops->func_hash->notrace_hash;
if (ftrace_hash_empty(hash))
- all = 1;
+ all = true;
} else {
inc = !inc;
hash = ops->func_hash->notrace_hash;
@@ -4028,6 +4033,9 @@ static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
free_ftrace_mod(ftrace_mod);
}
+ if (enable && list_empty(head))
+ new_hash->flags &= ~FTRACE_HASH_FL_MOD;
+
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
@@ -5035,9 +5043,11 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
if (file->f_mode & FMODE_WRITE) {
filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
- if (filter_hash)
+ if (filter_hash) {
orig_hash = &iter->ops->func_hash->filter_hash;
- else
+ if (!list_empty(&iter->tr->mod_trace))
+ iter->hash->flags |= FTRACE_HASH_FL_MOD;
+ } else
orig_hash = &iter->ops->func_hash->notrace_hash;
mutex_lock(&ftrace_lock);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d63550cdbdfa..13823951e42b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -773,10 +773,15 @@ struct ftrace_mod_load {
int enable;
};
+enum {
+ FTRACE_HASH_FL_MOD = (1 << 0),
+};
+
struct ftrace_hash {
unsigned long size_bits;
struct hlist_head *buckets;
unsigned long count;
+ unsigned long flags;
struct rcu_head rcu;
};
@@ -785,7 +790,7 @@ ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip);
static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
{
- return !hash || !hash->count;
+ return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
}
/* Standard output formatting function used for function return traces */