Re: FAILED: patch "[PATCH] of: fdt: add missing allocation-failure check" failed to apply to 4.4-stable tree

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, May 22, 2017 at 03:46:29PM -0500, Rob Herring wrote:
> On Mon, May 22, 2017 at 2:17 PM,  <gregkh@linuxfoundation.org> wrote:
> >
> > The patch below does not apply to the 4.4-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> >
> > thanks,
> >
> > greg k-h
> >
> > ------------------ original commit in Linus's tree ------------------
> >
> > From 49e67dd17649b60b4d54966e18ec9c80198227f0 Mon Sep 17 00:00:00 2001
> > From: Johan Hovold <johan@kernel.org>
> > Date: Wed, 17 May 2017 17:29:09 +0200
> > Subject: [PATCH] of: fdt: add missing allocation-failure check
> >
> > The memory allocator passed to __unflatten_device_tree() (e.g. a wrapped
> > kzalloc) can fail so add the missing sanity check to avoid dereferencing
> > a NULL pointer.
> >
> > Fixes: fe14042358fa ("of/flattree: Refactor unflatten_device_tree and add fdt_unflatten_tree")
> > Cc: stable <stable@vger.kernel.org>     # 2.6.38
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> > Signed-off-by: Rob Herring <robh@kernel.org>
> >
> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> > index a0972219ccfc..0373ae49d24d 100644
> > --- a/drivers/of/fdt.c
> > +++ b/drivers/of/fdt.c
> > @@ -507,6 +507,9 @@ void *__unflatten_device_tree(const void *blob,
> 
> The context looks the same, it's just the line number is 416 in v4.4.
> 
> >
> >         /* Allocate memory for the expanded device tree */
> >         mem = dt_alloc(size + 4, __alignof__(struct device_node));
> > +       if (!mem)
> > +               return NULL;
> > +

No, in 4.4 this function's return type is "void", not "void *" so the
build fails (well, has a warning, which means it isn't correct.)

thanks,

greg k-h