From 8b1291994d8e5e621a8af7e165b106e50d04bbf1 Mon Sep 17 00:00:00 2001 From: Jiaxing Wang Date: Fri, 6 Nov 2015 16:04:16 +0800 Subject: [PATCH] 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 Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2198a63..08af79c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -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); /* -- 2.7.4