Commit-ID: 3e1f60b80cafcb5d7e8d3665b35962fbb8fb9efa Gitweb: http://git.kernel.org/tip/3e1f60b80cafcb5d7e8d3665b35962fbb8fb9efa Author: Frederic Weisbecker <fweisbec@xxxxxxxxx> AuthorDate: Sun, 22 Mar 2009 23:10:45 +0100 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Mon, 23 Mar 2009 16:25:47 +0100 tracing/ftrace: check if debugfs is registered before creating files 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. Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- 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) { -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html