Re: [PATCH 1/9] trace: Fix uninitialized variable compiler warning

From: Jiri Olsa
Date: Mon Nov 28 2011 - 11:25:11 EST




On Mon, Nov 28, 2011 at 11:19:18AM -0500, Steven Rostedt wrote:
> On Sun, 2011-11-27 at 19:04 +0100, Jiri Olsa wrote:
> > Initialize page2 variable to make compiler happy.
>
> What compiler is this? Because this is a compiler bug. In fact, there's
> no check for page2 being NULL, so if it is used uninitialized it will
> crash the kernel. I don't like these "make the compiler shut up" fixes,
> because honestly, changes like this hide bugs.

[jolsa@krava1 ~]$ gcc --version
gcc (GCC) 4.4.5 20110214 (Red Hat 4.4.5-6)

>
> Nacked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

understood, np

jirka
>
> -- Steve
>
> >
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > kernel/trace/trace.c | 3 +--
> > 1 files changed, 1 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> > index 9e158cc..4a06862 100644
> > --- a/kernel/trace/trace.c
> > +++ b/kernel/trace/trace.c
> > @@ -3655,8 +3655,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
> > struct page *pages[2];
> > int nr_pages = 1;
> > ssize_t written;
> > - void *page1;
> > - void *page2;
> > + void *page1, *page2 = NULL;
> > int offset;
> > int size;
> > int len;
>
>
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