Re: [PATCH] util/cacheinfo: fix crash when compiling with uClibc

[Carlos Santos]

On Thu, Oct 17, 2019 at 9:47 AM Peter Maydell <address@hidden> wrote:
>
> On Thu, 17 Oct 2019 at 13:39, <address@hidden> wrote:
> >
> > From: Carlos Santos <address@hidden>
> >
> > uClibc defines _SC_LEVEL1_ICACHE_LINESIZE and _SC_LEVEL1_DCACHE_LINESIZE
> > but the corresponding sysconf calls returns -1, which is a valid result,
> > meaning that the limit is indeterminate.
> >
> > Handle this situation using the fallback values instead of crashing due
> > to an assertion failure.
> >
> > Signed-off-by: Carlos Santos <address@hidden>
> > ---
> >  util/cacheinfo.c | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/util/cacheinfo.c b/util/cacheinfo.c
> > index ea6f3e99bf..d94dc6adc8 100644
> > --- a/util/cacheinfo.c
> > +++ b/util/cacheinfo.c
> > @@ -93,10 +93,16 @@ static void sys_cache_info(int *isize, int *dsize)
> >  static void sys_cache_info(int *isize, int *dsize)
> >  {
> >  # ifdef _SC_LEVEL1_ICACHE_LINESIZE
> > -    *isize = sysconf(_SC_LEVEL1_ICACHE_LINESIZE);
> > +    int tmp_isize = (int) sysconf(_SC_LEVEL1_ICACHE_LINESIZE);
>
> Do we need the cast here ?

It's there to remind the reader that a type coercion may occur, since
sysconf() returns a long and isize is an int.

> > +    if (tmp_isize > 0) {
> > +        *isize = tmp_isize;
> > +    }
> >  # endif
> >  # ifdef _SC_LEVEL1_DCACHE_LINESIZE
> > -    *dsize = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
> > +    int tmp_dsize = (int) sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
> > +    if (tmp_dsize > 0) {
> > +        *dsize = tmp_dsize;
> > +    }
> >  # endif
> >  }
> >  #endif /* sys_cache_info */
> > --
>
> thanks
> -- PMM

-- 
Carlos Santos
Senior Software Maintenance Engineer
Red Hat
address@hidden    T: +55-11-3534-6186