[PATCH 2/2] tracing: Add free_trace_iter_content() helper function
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2023-07-13 15:47:11
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: "Steven Rostedt (Google)" <rostedt@goodmis.org> As the trace iterator is created and used by various interfaces, the clean up of it needs to be consistent. Create a free_trace_iter_content() helper function that frees the content of the iterator and use that to clean it up in all places that it is used. Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- kernel/trace/trace.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1c370ffbe062..3f38250637e2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c@@ -4815,6 +4815,25 @@ static const struct seq_operations tracer_seq_ops = { .show = s_show, }; +/* + * Note, as iter itself can be allocated and freed in different + * ways, this function is only used to free its content, and not + * the iterator itself. The only requirement to all the allocations + * is that it must zero all fields (kzalloc), as freeing works with + * ethier allocated content or NULL. + */ +static void free_trace_iter_content(struct trace_iterator *iter) +{ + /* The fmt is either NULL, allocated or points to static_fmt_buf */ + if (iter->fmt != static_fmt_buf) + kfree(iter->fmt); + + kfree(iter->temp); + kfree(iter->buffer_iter); + mutex_destroy(&iter->mutex); + free_cpumask_var(iter->started); +} + static struct trace_iterator * __tracing_open(struct inode *inode, struct file *file, bool snapshot) {
@@ -4922,8 +4941,7 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) fail: mutex_unlock(&trace_types_lock); - kfree(iter->temp); - kfree(iter->buffer_iter); + free_trace_iter_content(iter); release: seq_release_private(inode, file); return ERR_PTR(-ENOMEM);
@@ -5002,11 +5020,7 @@ static int tracing_release(struct inode *inode, struct file *file) mutex_unlock(&trace_types_lock); - mutex_destroy(&iter->mutex); - free_cpumask_var(iter->started); - kfree(iter->fmt); - kfree(iter->temp); - kfree(iter->buffer_iter); + free_trace_iter_content(iter); seq_release_private(inode, file); return 0;
@@ -6709,7 +6723,12 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) } trace_seq_init(&iter->seq); - iter->trace = tr->current_trace; + + iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL); + if (!iter->trace) + goto fail; + + *iter->trace = *tr->current_trace; if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { ret = -ENOMEM;
@@ -6763,10 +6782,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) mutex_unlock(&trace_types_lock); - free_cpumask_var(iter->started); - kfree(iter->fmt); - kfree(iter->temp); - mutex_destroy(&iter->mutex); + free_trace_iter_content(iter); kfree(iter); trace_array_put(tr);
--
2.40.1