On Fri, Jan 24, 2020 at 04:48:03PM +0000, Anton Ivanov wrote:
>
>
> On 24/01/2020 16:44, Dan Carpenter wrote:
> > On Fri, Jan 24, 2020 at 12:52:18PM +0000, Anton Ivanov wrote:
> > >
> > >
> > > On 24/01/2020 10:14, Dan Carpenter wrote:
> > > > 1) The uml_vector_user_bpf() returns pointers so it should return NULL
> > > > instead of false.
> > > > 2) If the "bpf_prog" allocation failed, it would have eventually lead to
> > > > a crash. We can't succeed after the error happens so it should just
> > > > return.
> > > >
> > > > Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers")
> > > > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > > > ---
> > > > arch/um/drivers/vector_user.c | 10 +++++-----
> > > > 1 file changed, 5 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c
> > > > index ddcd917be0af..88483f5b034c 100644
> > > > --- a/arch/um/drivers/vector_user.c
> > > > +++ b/arch/um/drivers/vector_user.c
> > > > @@ -732,13 +732,13 @@ void *uml_vector_user_bpf(char *filename)
> > > > if (stat(filename, &statbuf) < 0) {
> > > > printk(KERN_ERR "Error %d reading bpf file", -errno);
> > > > - return false;
> > > > + return NULL;
> > >
> > > I will sort this one out, thanks for noticing.
> > >
> > > > }
> > > > bpf_prog = uml_kmalloc(sizeof(struct sock_fprog), UM_GFP_KERNEL);
> > > > - if (bpf_prog != NULL) {
> > > > - bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter);
> > > > - bpf_prog->filter = NULL;
> > > > - }
> > > > + if (!pfg_prog)
> > >
> > > ^^^^^ ?
> >
> > If we don't return here it leads to a NULL dereference.
>
> It says pfg_prog
>
> I cannot find this identifier :)
>
Oh wow... That's very embarrassing. My QC scripts do compile these
as part of the process. But this wasn't a in of my allmodconfig
and when I do "make arch/um/drivers/vector_user.o", it just silently
returns without printing anything. I didn't notice that it hadn't
built.
Even "make V=2 arch/um/drivers/vector_user.o" doesn't generate output.
I will resend the patch (on Monday though).
regards,
dan carpenter
