Re: [PATCH] modpost: abort if a module symbol is too long

[Takashi Iwai <tiwai@suse.de>]

On Thu, 06 Aug 2015 23:09:12 +0200,
Rusty Russell wrote:
> 
> Takashi Iwai <tiwai@suse.de> writes:
> > Module symbols have a limited length, but currently the build system
> > allows the build finishing even if the driver code contains a too long
> > symbol name, which eventually overflows the modversion_info[] item.
> > The compiler may catch at compiling *.mod.c like
> >   CC      xxx.mod.o
> >   xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
> > but it's merely a warning.
> >
> > This patch adds the check of the symbol length in modpost and stops
> > the build properly.
> >
> > As of now, MODULE_NAME_LEN is copied in modpost.c.  At best, this
> > should be read directly from kernel headers.  But including
> > linux/module.h is too troublesome for now, so just paper over it.
> >
> > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > ---
> >  scripts/mod/modpost.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > index 12d3db3bd46b..25bda9d2868c 100644
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -2133,6 +2133,9 @@ static void add_staging_flag(struct buffer *b, const char *name)
> >  		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
> >  }
> >  
> > +/* FIXME: better to be included from kernel header */
> > +#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
> 
> This isn't quite right, since modpost handles cross-compilation.
> 
> #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
> 
> Should work...

Alright, I'll resubmit with this fix.


Thanks!

Takashi