[SRU Bionic][PATCH 0/2] Fix invalid syscall return for traced tasks

[Dan Streetman]

On Thu, Apr 22, 2021 at 4:09 AM Stefan Bader <stefan.bader at canonical.com> wrote:
>
> On 21.04.21 20:40, Dan Streetman wrote:
> > BugLink: https://bugs.launchpad.net/bugs/1895132
> >
> > For any traced task, that has _TIF_TRACED set, invalid syscalls are
> > sent to the tracing code, which returns EPERM instead of ENOSYS, and
> > breaks userspace.
> >
> > Note that in focal (5.4) the return value was the actual syscall number,
> > while in bionic the return value is EPERM. However either value breaks
> > userspace.
> >
> > This is causing narrow failures of hirsute containers on bionic hosts
> > that are running the 4.15 kernel, as detailed in bug 1916485.
> >
> > Sven Schnelle (2):
> >    s390/ptrace: return -ENOSYS when invalid syscall is supplied
> >    s390/ptrace: pass invalid syscall numbers to tracing
> >
> >   arch/s390/kernel/entry.S  |  2 +-
> >   arch/s390/kernel/ptrace.c | 23 ++++++++++++++---------
> >   2 files changed, 15 insertions(+), 10 deletions(-)
> >
>
> Cover email should contain the target series (:<kernel>) for simpler reviews.
> The bug task should have status and importance set (I did that). And just
> wnodering, have you not been subscribed to the kermel-team mailing list before?
> Just baecause now all your posts need moderation.

sorry, I'm probably subscribed as my full email instead of
'ddstreet@', i'll change that

>
> -Stefan
>