summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSteven Rostedt (VMware) <rostedt@goodmis.org>2019-10-11 17:56:57 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2019-10-12 20:40:21 -0400
commit9ef16693aff8137faa21d16ffe65bb9832d24d71 (patch)
tree7e23890397b42a49853612a91c2edb9f48f489f2
parent3ed270b129a45c7c502c819a4286b464a52dac61 (diff)
downloadlinux-sh-9ef16693aff8137faa21d16ffe65bb9832d24d71.tar.gz
ftrace: Get a reference counter for the trace_array on filter files
The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for an instance now. They need to take a reference to the instance otherwise there could be a race between accessing the files and deleting the instance. It wasn't until the :mod: caching where these file operations started referencing the trace_array directly. Cc: stable@vger.kernel.org Fixes: 673feb9d76ab3 ("ftrace: Add :mod: caching infrastructure to trace_array") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-rw-r--r--kernel/trace/ftrace.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 62a50bf399d6..32c2eb167de0 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3540,21 +3540,22 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
struct ftrace_hash *hash;
struct list_head *mod_head;
struct trace_array *tr = ops->private;
- int ret = 0;
+ int ret = -ENOMEM;
ftrace_ops_init(ops);
if (unlikely(ftrace_disabled))
return -ENODEV;
+ if (tr && trace_array_get(tr) < 0)
+ return -ENODEV;
+
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
- return -ENOMEM;
+ goto out;
- if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
- kfree(iter);
- return -ENOMEM;
- }
+ if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
+ goto out;
iter->ops = ops;
iter->flags = flag;
@@ -3584,13 +3585,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
if (!iter->hash) {
trace_parser_put(&iter->parser);
- kfree(iter);
- ret = -ENOMEM;
goto out_unlock;
}
} else
iter->hash = hash;
+ ret = 0;
+
if (file->f_mode & FMODE_READ) {
iter->pg = ftrace_pages_start;
@@ -3602,7 +3603,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
/* Failed */
free_ftrace_hash(iter->hash);
trace_parser_put(&iter->parser);
- kfree(iter);
}
} else
file->private_data = iter;
@@ -3610,6 +3610,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
out_unlock:
mutex_unlock(&ops->func_hash->regex_lock);
+ out:
+ if (ret) {
+ kfree(iter);
+ if (tr)
+ trace_array_put(tr);
+ }
+
return ret;
}
@@ -5037,6 +5044,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
mutex_unlock(&iter->ops->func_hash->regex_lock);
free_ftrace_hash(iter->hash);
+ if (iter->tr)
+ trace_array_put(iter->tr);
kfree(iter);
return 0;