From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
khorenko@virtuozzo.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Cyrill Gorcunov <gorcunov@openvz.org>,
xemul@virtuozzo.com, X86 ML <x86@kernel.org>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32)
Date: Fri, 10 Jun 2016 22:07:49 +0200 [thread overview]
Message-ID: <20160610200739.GA14789@redhat.com> (raw)
In-Reply-To: <CALCETrWD8cvyNqW_2rxSDd2A345nOv47t+i2JhrCU2V7TpPNBQ@mail.gmail.com>
On 06/09, Andy Lutomirski wrote:
>
> On Jun 6, 2016 3:21 PM, "Oleg Nesterov" <oleg@redhat.com> wrote:
> >
> > On 06/01, Dmitry Safonov wrote:
> > >
> > > Note, that this will work only if application has changed it's CS.
> >
> > So, suppose it changes it's CS and crashes,
> >
> > > If the application does 32-bit syscall with __USER_CS, ptrace
> > > @@ -1355,7 +1355,7 @@ void update_regset_xstate_info(unsigned int size, u64 xstate_mask)
> > > const struct user_regset_view *task_user_regset_view(struct task_struct *task)
> > > {
> > > #ifdef CONFIG_IA32_EMULATION
> > > - if (test_tsk_thread_flag(task, TIF_IA32))
> > > + if (!user_64bit_mode(task_pt_regs(task)))
> > > #endif
> >
> > then coredump will do fill_elf_header(view->e_machine) and use EM_X86_64
> > instead of EM_386, or vice versa...
> >
> > I simply can't understand is this better or worse, I guess gdb or any
> > other tool which looks at this coredump will be confused anyway.
> >
>
> I think it's better.
and I tend to agree, I didn't try to argue with this change, but
> CRIU will change CS and someone will make the
> restored process crash afterwards.
I don't understand what do you mean... could you explain?
IIRC, CRIU can't c/r the 32-bit applications, or this is no longer true?
Oleg.
next prev parent reply other threads:[~2016-06-10 20:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 13:11 [PATCH 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
2016-06-01 13:11 ` [PATCH 1/6] x86/vdso: unmap vdso blob on vvar mapping failure Dmitry Safonov
2016-06-01 13:11 ` [PATCH 2/6] x86/vdso: introduce do_map_vdso() and vdso_type enum Dmitry Safonov
2016-06-03 9:50 ` Cyrill Gorcunov
2016-06-03 10:03 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* Dmitry Safonov
2016-06-01 13:11 ` [PATCH 4/6] x86/coredump: use core regs, rather that TIF_IA32 flag Dmitry Safonov
2016-06-03 9:51 ` Cyrill Gorcunov
2016-06-03 9:56 ` Dmitry Safonov
2016-06-03 10:01 ` Cyrill Gorcunov
2016-06-06 20:45 ` Oleg Nesterov
2016-06-06 22:43 ` Oleg Nesterov
2016-06-08 13:28 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32) Dmitry Safonov
2016-06-03 9:57 ` Cyrill Gorcunov
2016-06-03 10:27 ` Dmitry Safonov
2016-06-03 10:41 ` Cyrill Gorcunov
2016-06-06 21:19 ` Oleg Nesterov
2016-06-07 11:38 ` Dmitry Safonov
2016-06-09 17:21 ` Andy Lutomirski
2016-06-10 20:07 ` Oleg Nesterov [this message]
2016-06-10 20:14 ` Andy Lutomirski
2016-06-13 13:50 ` Oleg Nesterov
2016-06-13 20:40 ` Andy Lutomirski
2016-06-14 14:34 ` Oleg Nesterov
2016-06-14 14:43 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags Dmitry Safonov
2016-06-04 5:08 ` Andy Lutomirski
2016-06-04 15:57 ` Dmitry Safonov
2016-06-01 13:15 ` [PATCH 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
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