[PATCH 5.10 76/83] tracing: Have option files inc the trace array ref count

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5.10-stable review patch.  If anyone has any objections, please let me know.


From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

commit 7e2cfbd2d3c86afcd5c26b5c4b1dd251f63c5838 upstream.

The option files update the options for a given trace array. For an
instance, if the file is opened and the instance is deleted, reading or
writing to the file will cause a use after free.

Up the ref count of the trace_array when an option file is opened.

Link: https://lkml.kernel.org/r/20230907024804.086679464@xxxxxxxxxxx
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@xxxxxxxxxx/

Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
 kernel/trace/trace.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8367,12 +8367,33 @@ trace_options_write(struct file *filp, c
 	return cnt;
+static int tracing_open_options(struct inode *inode, struct file *filp)
+	struct trace_option_dentry *topt = inode->i_private;
+	int ret;
+	ret = tracing_check_open_get_tr(topt->tr);
+	if (ret)
+		return ret;
+	filp->private_data = inode->i_private;
+	return 0;
+static int tracing_release_options(struct inode *inode, struct file *file)
+	struct trace_option_dentry *topt = file->private_data;
+	trace_array_put(topt->tr);
+	return 0;
 static const struct file_operations trace_options_fops = {
-	.open = tracing_open_generic,
+	.open = tracing_open_options,
 	.read = trace_options_read,
 	.write = trace_options_write,
 	.llseek	= generic_file_llseek,
+	.release = tracing_release_options,

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