From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: [kernel-hardening] Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core)
Date: Thu, 23 Jun 2016 21:11:23 +0200 [thread overview]
Message-ID: <20160623191123.GE30935@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160623143126.GA16664@redhat.com>
On Thu, Jun 23, 2016 at 04:31:26PM +0200, Oleg Nesterov wrote:
> On 06/22, Linus Torvalds wrote:
> >
> > Oleg, what do you think? Would it be reasonable to free the stack and
> > thread_info synchronously at exit time, clear the pointer (to catch
> > any odd use), and only RCU-delay the task_struct itself?
>
> I didn't see the patches yet, quite possibly I misunderstood... But no,
> I don't this we can do this (if we are not going to move ti->flags to
> task_struct at least).
Didn't we talk about using SLAB_DESTROY_BY_RCU for task_struct before?
If that is possible, a reuse in per-cpu cache is equally possible.
All we really want to guarantee is that the memory remains a
task_struct, it need not remain the same task, right?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core)
Date: Thu, 23 Jun 2016 21:11:23 +0200 [thread overview]
Message-ID: <20160623191123.GE30935@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160623143126.GA16664@redhat.com>
On Thu, Jun 23, 2016 at 04:31:26PM +0200, Oleg Nesterov wrote:
> On 06/22, Linus Torvalds wrote:
> >
> > Oleg, what do you think? Would it be reasonable to free the stack and
> > thread_info synchronously at exit time, clear the pointer (to catch
> > any odd use), and only RCU-delay the task_struct itself?
>
> I didn't see the patches yet, quite possibly I misunderstood... But no,
> I don't this we can do this (if we are not going to move ti->flags to
> task_struct at least).
Didn't we talk about using SLAB_DESTROY_BY_RCU for task_struct before?
If that is possible, a reuse in per-cpu cache is equally possible.
All we really want to guarantee is that the memory remains a
task_struct, it need not remain the same task, right?
next prev parent reply other threads:[~2016-06-23 19:11 UTC|newest]
Thread overview: 188+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 23:43 [kernel-hardening] [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 02/13] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 03/13] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-21 9:53 ` [kernel-hardening] " Matt Fleming
2016-06-21 9:53 ` Matt Fleming
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-21 9:46 ` [kernel-hardening] " Vladimir Davydov
2016-06-21 9:46 ` Vladimir Davydov
2016-06-21 9:46 ` Vladimir Davydov
2016-06-21 9:46 ` Vladimir Davydov
2016-06-22 7:35 ` [kernel-hardening] " Michal Hocko
2016-06-22 7:35 ` Michal Hocko
2016-06-22 7:35 ` Michal Hocko
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 05/13] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-21 9:54 ` [kernel-hardening] " Vladimir Davydov
2016-06-21 9:54 ` Vladimir Davydov
2016-06-21 9:54 ` Vladimir Davydov
2016-06-21 9:54 ` Vladimir Davydov
2016-06-22 7:38 ` [kernel-hardening] " Michal Hocko
2016-06-22 7:38 ` Michal Hocko
2016-06-22 7:38 ` Michal Hocko
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 06/13] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-21 7:30 ` [kernel-hardening] " Jann Horn
2016-06-21 7:30 ` Jann Horn
2016-06-21 16:59 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 16:59 ` Andy Lutomirski
2016-06-21 17:13 ` [kernel-hardening] " Kees Cook
2016-06-21 17:13 ` Kees Cook
2016-06-21 17:28 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 17:28 ` Andy Lutomirski
2016-06-21 18:32 ` [kernel-hardening] " Rik van Riel
2016-06-21 18:32 ` Rik van Riel
2016-06-21 19:44 ` [kernel-hardening] " Arnd Bergmann
2016-06-21 19:44 ` Arnd Bergmann
2016-06-21 19:43 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 19:43 ` Andy Lutomirski
2016-07-11 17:00 ` [kernel-hardening] " Andrey Ryabinin
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 07/13] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-20 23:43 ` [kernel-hardening] [PATCH v3 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
2016-06-20 23:43 ` Andy Lutomirski
2016-06-21 4:01 ` [kernel-hardening] Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Linus Torvalds
2016-06-21 4:01 ` Linus Torvalds
2016-06-21 16:45 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 16:45 ` Andy Lutomirski
2016-06-21 17:16 ` [kernel-hardening] " Linus Torvalds
2016-06-21 17:16 ` Linus Torvalds
2016-06-21 17:27 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 17:27 ` Andy Lutomirski
2016-06-21 18:12 ` [kernel-hardening] " Kees Cook
2016-06-21 18:12 ` Kees Cook
2016-06-21 18:19 ` [kernel-hardening] " Rik van Riel
2016-06-21 18:19 ` Rik van Riel
2016-06-23 1:22 ` [kernel-hardening] " Andy Lutomirski
2016-06-23 1:22 ` Andy Lutomirski
2016-06-23 6:02 ` [kernel-hardening] " Linus Torvalds
2016-06-23 6:02 ` Linus Torvalds
2016-06-23 14:31 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 14:31 ` Oleg Nesterov
2016-06-23 16:30 ` [kernel-hardening] " Linus Torvalds
2016-06-23 16:30 ` Linus Torvalds
2016-06-23 16:41 ` [kernel-hardening] " Andy Lutomirski
2016-06-23 16:41 ` Andy Lutomirski
2016-06-23 17:10 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 17:10 ` Oleg Nesterov
2016-09-06 16:19 ` [kernel-hardening] " Jann Horn
2016-09-06 16:19 ` Jann Horn
2016-09-06 16:40 ` [kernel-hardening] " Andy Lutomirski
2016-09-06 16:40 ` Andy Lutomirski
2016-06-23 17:03 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 17:03 ` Oleg Nesterov
2016-06-23 17:44 ` [kernel-hardening] " Linus Torvalds
2016-06-23 17:44 ` Linus Torvalds
2016-06-23 17:52 ` [kernel-hardening] " Linus Torvalds
2016-06-23 17:52 ` Linus Torvalds
2016-06-23 18:00 ` [kernel-hardening] " Kees Cook
2016-06-23 18:00 ` Kees Cook
2016-06-23 18:54 ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:54 ` Peter Zijlstra
2016-06-23 18:12 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 18:12 ` Oleg Nesterov
2016-06-23 18:55 ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:55 ` Peter Zijlstra
2016-06-23 18:46 ` [kernel-hardening] " Linus Torvalds
2016-06-23 18:46 ` Linus Torvalds
2016-06-23 19:08 ` [kernel-hardening] " Andy Lutomirski
2016-06-23 19:08 ` Andy Lutomirski
2016-06-23 18:53 ` [kernel-hardening] " Peter Zijlstra
2016-06-23 18:53 ` Peter Zijlstra
2016-06-23 19:09 ` [kernel-hardening] " Andy Lutomirski
2016-06-23 19:09 ` Andy Lutomirski
2016-06-23 19:13 ` [kernel-hardening] " Peter Zijlstra
2016-06-23 19:13 ` Peter Zijlstra
2016-06-23 19:17 ` [kernel-hardening] " Linus Torvalds
2016-06-23 19:17 ` Linus Torvalds
2016-06-24 6:17 ` [kernel-hardening] " Linus Torvalds
2016-06-24 6:17 ` Linus Torvalds
2016-06-24 12:25 ` [kernel-hardening] " Brian Gerst
2016-06-24 12:25 ` Brian Gerst
2016-06-24 17:21 ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:21 ` Linus Torvalds
2016-06-24 17:40 ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:40 ` Linus Torvalds
2016-06-24 17:47 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 17:47 ` Andy Lutomirski
2016-06-24 17:56 ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:56 ` Linus Torvalds
2016-06-24 18:36 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 18:36 ` Andy Lutomirski
2016-06-24 17:51 ` [kernel-hardening] " Linus Torvalds
2016-06-24 17:51 ` Linus Torvalds
2016-06-24 18:11 ` [kernel-hardening] " Linus Torvalds
2016-06-24 18:11 ` Linus Torvalds
2016-06-24 20:25 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 20:25 ` Josh Poimboeuf
2016-06-24 20:51 ` [kernel-hardening] " Josh Poimboeuf
2016-06-24 20:51 ` Josh Poimboeuf
2016-06-24 20:53 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 20:53 ` Andy Lutomirski
2016-06-24 21:06 ` [kernel-hardening] " Linus Torvalds
2016-06-24 21:06 ` Linus Torvalds
2016-06-24 21:25 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 21:25 ` Andy Lutomirski
2016-06-24 21:32 ` [kernel-hardening] " Linus Torvalds
2016-06-24 21:32 ` Linus Torvalds
2016-06-24 21:34 ` [kernel-hardening] " Andy Lutomirski
2016-06-24 21:34 ` Andy Lutomirski
2016-06-25 2:41 ` [kernel-hardening] " Linus Torvalds
2016-06-25 2:41 ` Linus Torvalds
2016-06-25 23:19 ` [kernel-hardening] " Andy Lutomirski
2016-06-25 23:19 ` Andy Lutomirski
2016-06-25 23:30 ` [kernel-hardening] " Andy Lutomirski
2016-06-25 23:30 ` Andy Lutomirski
2016-06-26 1:23 ` [kernel-hardening] " Linus Torvalds
2016-06-26 1:23 ` Linus Torvalds
2016-06-23 18:52 ` [kernel-hardening] " Oleg Nesterov
2016-06-23 18:52 ` Oleg Nesterov
2016-06-24 14:05 ` [kernel-hardening] " Michal Hocko
2016-06-24 14:05 ` Michal Hocko
2016-06-24 15:06 ` [kernel-hardening] " Michal Hocko
2016-06-24 15:06 ` Michal Hocko
2016-06-24 15:06 ` Michal Hocko
2016-06-24 15:06 ` Michal Hocko
2016-06-24 20:22 ` [kernel-hardening] " Oleg Nesterov
2016-06-24 20:22 ` Oleg Nesterov
2016-06-27 10:36 ` [kernel-hardening] " Michal Hocko
2016-06-27 10:36 ` Michal Hocko
2016-06-23 19:11 ` Peter Zijlstra [this message]
2016-06-23 19:11 ` Peter Zijlstra
2016-06-23 19:34 ` [kernel-hardening] " Linus Torvalds
2016-06-23 19:34 ` Linus Torvalds
2016-06-23 19:46 ` [kernel-hardening] " Peter Zijlstra
2016-06-23 19:46 ` Peter Zijlstra
2016-06-21 9:24 ` [kernel-hardening] " Arnd Bergmann
2016-06-21 9:24 ` Arnd Bergmann
2016-06-21 17:16 ` [kernel-hardening] " Kees Cook
2016-06-21 17:16 ` Kees Cook
2016-06-21 18:02 ` [kernel-hardening] " Rik van Riel
2016-06-21 18:02 ` Rik van Riel
2016-06-21 18:05 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 18:05 ` Andy Lutomirski
2016-06-21 19:47 ` [kernel-hardening] " Arnd Bergmann
2016-06-21 19:47 ` Arnd Bergmann
2016-06-21 19:47 ` [kernel-hardening] " Andy Lutomirski
2016-06-21 19:47 ` Andy Lutomirski
2016-06-21 20:18 ` [kernel-hardening] " Kees Cook
2016-06-21 20:18 ` Kees Cook
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