On Thu, Feb 10, 2011 at 04:23:55PM +0100, Michal Marek wrote:
> On 5.2.2011 00:16, Ulf Magnusson wrote:
> > The Kconfig
> >
> > config FOO
> > bool "FOO" if BAR
> > select BAR
> >
> > has a dependency loop involving an undefined symbol BAR. This causes a
> > segfault in sym_check_print_recursive() as it assumes all symbols have a
> > non-null 'prop', which is not the case for undefined symbols. This is a
> > proposed fix.
> >
> > Signed-off-by: Ulf Magnusson <ulfalizer.lkml@xxxxxxxxx>
> > ---
> > scripts/kconfig/symbol.c | 32 ++++++++++++++++++++++++++++----
> > 1 files changed, 28 insertions(+), 4 deletions(-)
> >
> > diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
> > index a796c95..81a217f 100644
> > --- a/scripts/kconfig/symbol.c
> > +++ b/scripts/kconfig/symbol.c
> > @@ -5,6 +5,7 @@
> >
> > #include <ctype.h>
> > #include <stdlib.h>
> > +#include <stdio.h>
> > #include <string.h>
> > #include <regex.h>
> > #include <sys/utsname.h>
> > @@ -972,6 +973,10 @@ static void sym_check_print_recursive(struct symbol *last_sym)
> > struct menu *menu = NULL;
> > struct property *prop;
> > struct dep_stack cv_stack;
> > + const char *filename;
> > + int lineno;
> > + char undef_msg_buf[100];
> > + int snprintf_size;
> >
> > if (sym_is_choice_value(last_sym)) {
> > dep_stack_insert(&cv_stack, last_sym);
> > @@ -1001,18 +1006,37 @@ static void sym_check_print_recursive(struct symbol *last_sym)
> > break;
> > }
> > }
> > +
> > + if (prop) {
> > + filename = prop->file->name;
> > + lineno = prop->lineno;
> > + } else {
> > + /* The dependency loop involves an undefined symbol.
> > + * Checking sym->name is probably unnecessary here, but
> > + * just to be on the safe side. */
> > + snprintf_size = snprintf(undef_msg_buf,
> > + sizeof(undef_msg_buf),
> > + "<no file, %s is undefined>",
> > + sym->name ? sym->name :
> > + "<choice>");
> > + if (snprintf_size > sizeof(undef_msg_buf))
> > + undef_msg_buf[sizeof(undef_msg_buf) - 1] = '\0';
> > + filename = undef_msg_buf;
> > + lineno = 0;
>
> Good catch. But as this handles a corner case involving a severely
> borken Kconfig file, I would simply do
> filename = "<unknown>";
> lineno = 0;
> and be done with it.
>
Yeah, it probably isn't very likely to occur in practise, though it
would also happen if a symbol selects an undefined symbol it depends on
via an enclosing menu or if.
Pick whatever version you prefer :)
/Ulf
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