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Groups > linux.kernel > #1206958
| From | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu |
| Date | 2015-08-13 18:50 +0200 |
| Message-ID | <pX3Rw-w6-1@gated-at.bofh.it> (permalink) |
| References | (15 earlier) <pX3eO-8ec-17@gated-at.bofh.it> <pX3ou-8pv-13@gated-at.bofh.it> <pX3y9-92-5@gated-at.bofh.it> <pX3y9-92-3@gated-at.bofh.it> <pX3HQ-kx-39@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Aug 13, 2015 at 9:38 AM, Stas Sergeev <stsp@list.ru> wrote: > 13.08.2015 19:24, Andy Lutomirski пишет: > >> On Thu, Aug 13, 2015 at 9:20 AM, Stas Sergeev <stsp@list.ru> wrote: >>> >>> 13.08.2015 19:09, Andy Lutomirski пишет: >>> >>>> On Thu, Aug 13, 2015 at 9:03 AM, Stas Sergeev <stsp@list.ru> wrote: >>>>> >>>>> 13.08.2015 18:38, Andy Lutomirski пишет: >>>>>> >>>>>> >>>>>> So... what do we do about it? We could revert the whole mess. We >>>>>> could tell everyone to fix their DOSEMU, which violates policy and is >>>>>> especially annoying given how much effort we've put into keeping >>>>>> 16-bit mode fully functional lately. We could add yet more heuristics >>>>>> and teach sigreturn to ignore the saved SS value in sigcontext if the >>>>>> saved CS is 64-bit and the saved SS is unusable. >>>>> >>>>> Andy, why do you constantly ignore the proposal to make >>>>> new behaviour explicitly controlable? You don't have to agree >>>>> with it, but you could at least comment on that possibility >>>>> and/or mention it with the ones you listed above. >>>> >>>> I'm not sure what the proposal is exactly. >>>> >>>> We could add a new uc_flags flag. If set, it means that >>>> sigcontext->ss is valid and should be used by sigreturn. If clear, >>>> then we ignore sigcontext->ss and just restore __USER_DS. >>>> >>>> The problem is that, by itself, this won't fix old DOSEMU. We somehow >>>> need to either detect that something funny is going on or just leave >>>> the flag clear by default. >>>> >>>> We could do this: always save SS to sigcontext->ss, but only restore >>>> sigcontext->ss if userspace explicitly sets the flag before sigreturn. >>>> If we do that, we'd need to also add my patch to preserve the actual >>>> HW SS selector if possible so that old DOSEMU knows what SS to program >>>> into its trampoline. >>>> >>>> This at least lets *new* DOSEMU set the flag and get the improved >>>> behavior. I still don't know what effect it'll have on Wine and CRIU. >>>> >>>> Stas, is that what you were thinking, or were you thinking of something >>>> else? >>> >>> Not quite. >>> I mean the flag that will control not only sigreturn, but >>> the signal delivery as well. This may probably be a sigaction() >>> flag or some other. If not set - ss is ignored by both signal >>> delivery and sigreturn(). If set - ss is saved/restored (and in >>> the future - also fs/gs). >>> Is such a flag possible? >> >> Maybe. I think I'm more nervous about adding new flags in sigaction >> than I am in uc_flags. > > Isn't uc_flags read-only for the user? > I look into setup_rt_frame > <http://lxr.free-electrons.com/ident?v=2.4.37;i=setup_rt_frame>() and see > --- > /* Create the ucontext. */ > err |= __put_user(0, &frame->uc.uc_flags); > --- > so it doesn't look like the flag that user can use to _request_ > something from the kernel. And I am talking about exactly > the flag to request the new behaviour, as only that can remove > the regression completely without patching dosemu. User code could rewrite it in the signal handler to request something. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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[regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 02:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 02:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 10:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 18:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 19:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 20:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 21:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 21:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 22:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 22:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 22:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 22:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 22:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 23:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-12 23:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 00:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 00:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Ingo Molnar <mingo@kernel.org> - 2015-08-13 10:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 12:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 14:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 17:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 17:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 17:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 18:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 18:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 18:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 18:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 18:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 18:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 19:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 19:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 19:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 20:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 20:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 20:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 20:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 20:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 18:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 13:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-12 22:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 17:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 17:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 18:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 18:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 18:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 18:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 18:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Brian Gerst <brgerst@gmail.com> - 2015-08-13 19:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-18 08:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-19 00:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-19 11:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-19 17:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-19 18:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-19 00:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-19 12:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-19 17:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Cyrill Gorcunov <gorcunov@gmail.com> - 2015-08-14 10:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 20:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 20:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 20:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 21:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 21:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 22:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 22:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Cyrill Gorcunov <gorcunov@gmail.com> - 2015-08-13 22:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 22:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Raymond Jennings <shentino@gmail.com> - 2015-08-13 23:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 23:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Raymond Jennings <shentino@gmail.com> - 2015-08-14 00:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 00:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 01:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 01:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Raymond Jennings <shentino@gmail.com> - 2015-08-14 01:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 01:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 02:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 00:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 00:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 00:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 00:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 01:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 01:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 01:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 02:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 02:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 02:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 03:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 03:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 03:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 04:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-18 08:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 03:40 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 02:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-14 02:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 02:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-14 02:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Cyrill Gorcunov <gorcunov@gmail.com> - 2015-08-14 09:30 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Pavel Emelyanov <xemul@parallels.com> - 2015-08-14 12:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Cyrill Gorcunov <gorcunov@gmail.com> - 2015-08-14 13:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 21:00 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Andy Lutomirski <luto@amacapital.net> - 2015-08-13 21:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 21:20 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 21:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 22:10 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-18 08:50 +0200
Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu Stas Sergeev <stsp@list.ru> - 2015-08-13 22:10 +0200
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