Commit 8b129199 authored Nov 06, 2015 by Jiaxing Wang Committed by Steven Rostedt Nov 06, 2015

tracing: Make tracing work when debugfs is not configured in

Currently tracing_init_dentry() returns -ENODEV when debugfs is not
configured in, which causes tracefs not populated with tracing files and
directories, so we will get an empty directory even after we manually
mount tracefs.

We can make tracing_init_dentry() return NULL if debugfs is not
configured in and can manually mount tracefs. But return -ENODEV
if debugfs is configured in but not initialized or failed to create
automount point as that would break backward compatibility with older
tools.

Link: http://lkml.kernel.org/r/1446797056-11683-1-git-send-email-hello.wjx@gmail.com



Signed-off-by: Jiaxing Wang <hello.wjx@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent d227c3ae

kernel/trace/trace.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -6847,7 +6847,9 @@ struct dentry *tracing_init_dentry(void)
		if (tr->dir)
		return NULL;

		if (WARN_ON(!debugfs_initialized()))
		if (WARN_ON(!tracefs_initialized()) \|\|
		(IS_ENABLED(CONFIG_DEBUG_FS) &&
		WARN_ON(!debugfs_initialized())))
		return ERR_PTR(-ENODEV);

		/*

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