[Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()

[Alexei Starovoitov]

On Mon, Jul 13, 2020 at 9:38 PM Andrii Nakryiko
<andrii.nakryiko at gmail.com> wrote:
>
> On Mon, Jul 13, 2020 at 6:29 PM Peilin Ye <yepeilin.cs at gmail.com> wrote:
> >
> > Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
> > as NULL. This patch fixes the following syzbot bug:
> >
> >     https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355

The link looks wrong?
Nothing in the stack trace indicates this issue.

> > Reported-by: syzbot+ee09bda7017345f1fbe6 at syzkaller.appspotmail.com
> > Signed-off-by: Peilin Ye <yepeilin.cs at gmail.com>
> > ---
> > Thank you for reviewing my patch! I am new to Linux kernel development; would
> > the log message and errno be appropriate for this case?
>
> I think it's good enough, thanks for the fix.
>
> Acked-by: Andrii Nakryiko <andriin at fb.com>
>
> >
> > Change in v2:
> >     - Split NULL and IS_ERR cases.
> >
> >  kernel/bpf/btf.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
>
> [...]