Re: [Qemu-devel] [PATCH v6 10/10] block/vvfat: fix setbuf stream parameter may be NULL

[zhanghailiang]

On 2014/8/14 18:36, Michael S. Tsirkin wrote:
> On Thu, Aug 14, 2014 at 03:29:21PM +0800, zhanghailiang wrote:
> > From: Li Liu<address@hidden>
> >
> > fopen() may return NULL which will cause setbuf() segmentfault
> >
> > Signed-off-by: zhanghailiang<address@hidden>
> > Signed-off-by: Li Liu<address@hidden>
> > ---
> >   block/vvfat.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/block/vvfat.c b/block/vvfat.c
> > index 70176b1..6889ea9 100644
> > --- a/block/vvfat.c
> > +++ b/block/vvfat.c
> > @@ -1084,7 +1084,10 @@ static int vvfat_open(BlockDriverState *bs, QDict 
> > *options, int flags,
> >
> >   DLOG(if (stderr == NULL) {
> >       stderr = fopen("vvfat.log", "a");
> > -    setbuf(stderr, NULL);
> > +
> > +    if (stderr) {
> > +        setbuf(stderr, NULL);
> > +    }
> >   })
> >
> >       opts = qemu_opts_create(&runtime_opts, NULL, 0,&error_abort);
>
> I would say assert on failure here.
> If one is trying to debug, seeing no output will just confuse
> matters more.

OK, i will change it to use assert here, thanks.