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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Oleg Nesterov <oleg@redhat.com>,
	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>,
	"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: Fri, 24 Jun 2016 10:40:46 -0700	[thread overview]
Message-ID: <CA+55aFyu=G09-Qg=M-7CmAudS1Mj+OZMPNerd9VfUwvNk8VL+Q@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFwJ1=pyr9fP_UzDjnyX2qJ4mpxg_DTTiOJTv9PFW4dHgg@mail.gmail.com>

On Fri, Jun 24, 2016 at 10:21 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> But as mentioned, I must have missed something. There were a number of
> places where the code used the task_stack_page() and
> task_thread_info() interchangably, which used to work and is no longer
> true. There might simply be cases I missed.

.. and immediately as I wrote that, I went "Duh".

One place I missed was free_thread_info(), which should now free the
stack, not the ti pointer. But it does

        struct page *page = virt_to_page(ti);

and frees that, which is bogus. It turns out that we do do

        free_thread_info(tsk->stack);

which is bogus too, and undoes it, but I think I have a few new places
to look at..

                Linus

  reply	other threads:[~2016-06-24 17:40 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-20 23:43 [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-20 23:43 ` [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 ` [PATCH v3 03/13] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski
2016-06-21  9:53   ` Matt Fleming
2016-06-20 23:43 ` [PATCH v3 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-21  9:46   ` Vladimir Davydov
2016-06-22  7:35   ` Michal Hocko
2016-06-20 23:43 ` [PATCH v3 05/13] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski
2016-06-21  9:54   ` Vladimir Davydov
2016-06-22  7:38   ` Michal Hocko
2016-06-20 23:43 ` [PATCH v3 06/13] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-21  7:30   ` Jann Horn
2016-06-21 16:59     ` Andy Lutomirski
2016-06-21 17:13       ` Kees Cook
2016-06-21 17:28         ` Andy Lutomirski
2016-06-21 18:32         ` [kernel-hardening] " Rik van Riel
2016-06-21 19:44           ` Arnd Bergmann
2016-06-21 19:43             ` Andy Lutomirski
2016-07-11 17:00           ` Andrey Ryabinin
2016-06-20 23:43 ` [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 ` [PATCH v3 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-20 23:43 ` [PATCH v3 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
2016-06-21  4:01 ` [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) Linus Torvalds
2016-06-21 16:45   ` Andy Lutomirski
2016-06-21 17:16     ` Linus Torvalds
2016-06-21 17:27       ` Andy Lutomirski
2016-06-21 18:12         ` Kees Cook
2016-06-21 18:19           ` [kernel-hardening] " Rik van Riel
2016-06-23  1:22   ` Andy Lutomirski
2016-06-23  6:02     ` Linus Torvalds
2016-06-23 14:31       ` Oleg Nesterov
2016-06-23 16:30         ` Linus Torvalds
2016-06-23 16:41           ` Andy Lutomirski
2016-06-23 17:10             ` Oleg Nesterov
2016-09-06 16:19             ` Jann Horn
2016-09-06 16:40               ` Andy Lutomirski
2016-06-23 17:03           ` Oleg Nesterov
2016-06-23 17:44             ` Linus Torvalds
2016-06-23 17:52               ` Linus Torvalds
2016-06-23 18:00                 ` Kees Cook
2016-06-23 18:54                   ` Peter Zijlstra
2016-06-23 18:12                 ` Oleg Nesterov
2016-06-23 18:55                   ` Peter Zijlstra
2016-06-23 18:46                 ` Linus Torvalds
2016-06-23 19:08                   ` Andy Lutomirski
2016-06-23 18:53                 ` Peter Zijlstra
2016-06-23 19:09                   ` Andy Lutomirski
2016-06-23 19:13                     ` Peter Zijlstra
2016-06-23 19:17                   ` Linus Torvalds
2016-06-24  6:17                     ` Linus Torvalds
2016-06-24 12:25                       ` Brian Gerst
2016-06-24 17:21                         ` Linus Torvalds
2016-06-24 17:40                           ` Linus Torvalds [this message]
2016-06-24 17:47                             ` Andy Lutomirski
2016-06-24 17:56                               ` Linus Torvalds
2016-06-24 18:36                                 ` Andy Lutomirski
2016-06-24 17:51                             ` Linus Torvalds
2016-06-24 18:11                               ` Linus Torvalds
2016-06-24 20:25                                 ` Josh Poimboeuf
2016-06-24 20:51                                   ` Josh Poimboeuf
2016-06-24 20:53                                     ` Andy Lutomirski
2016-06-24 21:06                                     ` Linus Torvalds
2016-06-24 21:25                                       ` Andy Lutomirski
2016-06-24 21:32                                         ` Linus Torvalds
2016-06-24 21:34                                           ` Andy Lutomirski
2016-06-25  2:41                                             ` Linus Torvalds
2016-06-25 23:19                                               ` Andy Lutomirski
2016-06-25 23:30                                                 ` Andy Lutomirski
2016-06-26  1:23                                                   ` Linus Torvalds
2016-06-23 18:52               ` Oleg Nesterov
2016-06-24 14:05                 ` Michal Hocko
2016-06-24 15:06                   ` Michal Hocko
2016-06-24 20:22                     ` Oleg Nesterov
2016-06-27 10:36                       ` Michal Hocko
2016-06-23 19:11         ` Peter Zijlstra
2016-06-23 19:34           ` Linus Torvalds
2016-06-23 19:46             ` Peter Zijlstra
2016-06-21  9:24 ` Arnd Bergmann
2016-06-21 17:16   ` Kees Cook
2016-06-21 18:02     ` [kernel-hardening] " Rik van Riel
2016-06-21 18:05       ` Andy Lutomirski
2016-06-21 19:47     ` Arnd Bergmann
2016-06-21 19:47       ` Andy Lutomirski
2016-06-21 20:18         ` Kees Cook

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