lkml.org 
[lkml]   [2009]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/5] tracing/ftrace: check if debugfs is registered before creating files

* Steven Rostedt <rostedt@goodmis.org> wrote:

>
> On Sun, 22 Mar 2009, Frederic Weisbecker wrote:
>
> > 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);
> >
>
> Hmm, those tracers should separate out the debugfs code, and put
> it into a fs_initcall(), where debugfs should already initialized.

indeed, this seems much cleaner and we'll have the debugfs
structures initialized as well.

Ingo


\
 
 \ /
  Last update: 2009-03-23 20:25    [W:0.132 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site