Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 3/5] tracing/ftrace: check if debugfs is registered before creating files | Date | Sun, 22 Mar 2009 23:10:45 +0100 |
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Impact: fix a crash with ftrace={nop,boot} parameter
If the nop or initcall tracers are launched as boot tracers, they will attempt to create their option directory and files. But these tracers are registered very early and then assigned as "boot tracers" very early if asked to.
Since they do this before debugfs has been registered (core initcall), a crash is triggered.
Another early tracers could also come later. So we fix it by checking if debugfs is initialized before creating the root tracing directory.
Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- kernel/trace/trace.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ace685c..f0e1337 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3513,6 +3513,9 @@ struct dentry *tracing_init_dentry(void) if (d_tracer) return d_tracer; + if (!debugfs_initialized()) + return NULL; + d_tracer = debugfs_create_dir("tracing", NULL); if (!d_tracer && !once) { -- 1.6.1
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