For architectures like aarch64/ppc64 it's needed to propagate the size
of page inside PIEs. For the parasite page size will be defined during
seizing, and for restorer during early initialization.
Afterward we can use PAGE_SIZE in PIEs like we did before.
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Why should we have self-unmapping code in parasite?
It looks like, we can drop this code using simple sys_unmap()
injection (like that I did for `criu exec` action and for cases where we
failed to insert parasite by some reason, but still need to unmap remotes).
It's an RFC, so just a suggestion - maybe I miss something you have in
mind - please, describe that/those things.
My motivation is:
- less code, defined commands for PIE, one BUG() less, one jump to PIE less
- I'm making one 64-bit parasite on x86 instead of two 32 and 64 bit.
It works (branch 32-one-parasite) with long-jump in the beginning to
64-bit code from 32-bit task.
On parasite curing it sig-returns from 64-bit parasite to 32-bit task,
this point we're trapping in CRIU. After that we command parasite to
unmap itself, so it long-jumps again to parasite 64-bit code, unmaps,
we caught task after sys_unmap and the task is with 64-bit CS.
We can't set 32-bit registers after this - kernel checks that
registers set is the same on PTRACE_SETREGSET:
> > static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
> > struct iovec *kiov)
...
> > if (!regset || (kiov->iov_len % regset->size) != 0)
> > return -EINVAL;
So, to return again to 32-bit task I need sigreturn() again or add
long-jump with 32-bit CS.
I've disable that for 32-bit testing with (in compel_cure_remote):
- if (ctl->addr_cmd) {
+ if (ctl->addr_cmd && user_regs_native(&ctl->orig.regs)) {
And it works. It also works for native tasks, so why should we keep it?
travis-ci: success for compel: kill self-unmap in parasite
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This is the final patch in the series. It does a bunch
of renames and fixes headers respectively.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
