Re: Runtime trouble with commit dbd952127d (seccomp: introduce writer locking)

[Oleg Nesterov <oleg@redhat.com>]

On 08/09, Kees Cook wrote:
>
> On Sat, Aug 9, 2014 at 6:47 PM, Guenter Roeck <private@roeck-us.net> wrote:
> > Hi folks,
> >
> > I am having some trouble with commit dbd952127d (seccomp: introduce
> > writer locking) when running my qemu tests on the upstream kernel.
>
> Eek, sorry this is causing you trouble!
>
> > With powerpc, I get the following crash.
> >
> > ftrace: allocating 20093 entries in 59 pages
> > ------------[ cut here ]------------
> > kernel BUG at kernel/fork.c:1108!
>
> For your tree, does this resolve to copy_seccomp()'s
>
>         BUG_ON(!spin_is_locked(&current->sighand->siglock));
>
> line?

This is almost off-topic, and I too do not understand whats going on...

But I'd suggest to change this check to use  lockdep_is_held() in any
case.

Oleg.