From: Nadav Amit <nadav.amit@gmail.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
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Ben Segall <bsegall@google.com>,
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dianders@chromium.org, dietmar.eggemann@arm.com,
eric.devolder@oracle.com, Heiko Carstens <hca@linux.ibm.com>,
"hch@infradead.org" <hch@infradead.org>,
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"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
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Ingo Molnar <mingo@redhat.com>,
mjguzik@gmail.com, "Michael S. Tsirkin" <mst@redhat.com>,
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"Peter Zijlstra (Intel)" <peterz@infradead.org>,
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Rick P Edgecombe <rick.p.edgecombe@intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Suren Baghdasaryan <surenb@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Uladzislau Rezki <urezki@gmail.com>,
vincent.guittot@linaro.org,
Valentin Schneider <vschneid@redhat.com>
Subject: Re: [RFC 11/14] x86: add support for Dynamic Kernel Stacks
Date: Tue, 12 Mar 2024 09:20:40 +0200 [thread overview]
Message-ID: <32BCF7CC-CBE8-45AD-B3D8-2856DD4FFF30@gmail.com> (raw)
In-Reply-To: <11e673cf-8bfa-4493-ab86-2f1f97ddd732@app.fastmail.com>
> On 12 Mar 2024, at 2:02, Andy Lutomirski <luto@kernel.org> wrote:
>
> Doesn't this buy a new problem? Install a page, run the thread without using the page but speculatively load the PTE as read-only into the TLB, context-switch out the thread, (entirely safely and correctly) determine that the page wasn't used, remove it from the PTE, use it for something else and fill it with things that aren't zero, run the thread again, and read from it. Now it has some other thread's data!
Yes, you are correct. Bad idea of mine. Regardless of data leak, it opens the door for subtle hard-to-analyze bugs where 2 reads return different values.
next prev parent reply other threads:[~2024-03-12 7:20 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-11 16:46 [RFC 00/14] Dynamic Kernel Stacks Pasha Tatashin
2024-03-11 16:46 ` [RFC 01/14] task_stack.h: remove obsolete __HAVE_ARCH_KSTACK_END check Pasha Tatashin
2024-03-17 14:36 ` Christophe JAILLET
2024-03-17 15:13 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 02/14] fork: Clean-up ifdef logic around stack allocation Pasha Tatashin
2024-03-11 16:46 ` [RFC 03/14] fork: Clean-up naming of vm_strack/vm_struct variables in vmap stacks code Pasha Tatashin
2024-03-17 14:42 ` Christophe JAILLET
2024-03-19 16:32 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 04/14] fork: Remove assumption that vm_area->nr_pages equals to THREAD_SIZE Pasha Tatashin
2024-03-17 14:45 ` Christophe JAILLET
2024-03-17 15:14 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 05/14] fork: check charging success before zeroing stack Pasha Tatashin
2024-03-12 15:57 ` Kirill A. Shutemov
2024-03-12 16:52 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 06/14] fork: zero vmap stack using clear_page() instead of memset() Pasha Tatashin
2024-03-12 7:15 ` Nikolay Borisov
2024-03-12 16:53 ` Pasha Tatashin
2024-03-14 7:55 ` Christophe Leroy
2024-03-14 13:52 ` Pasha Tatashin
2024-03-17 14:48 ` Christophe JAILLET
2024-03-17 15:15 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 07/14] fork: use the first page in stack to store vm_stack in cached_stacks Pasha Tatashin
2024-03-11 16:46 ` [RFC 08/14] fork: separate vmap stack alloction and free calls Pasha Tatashin
2024-03-14 15:18 ` Jeff Xie
2024-03-14 17:14 ` Pasha Tatashin
2024-03-17 14:51 ` Christophe JAILLET
2024-03-17 15:15 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 09/14] mm/vmalloc: Add a get_vm_area_node() and vmap_pages_range_noflush() public functions Pasha Tatashin
2024-03-11 16:46 ` [RFC 10/14] fork: Dynamic Kernel Stacks Pasha Tatashin
2024-03-11 19:32 ` Randy Dunlap
2024-03-11 19:55 ` Pasha Tatashin
2024-03-11 16:46 ` [RFC 11/14] x86: add support for " Pasha Tatashin
2024-03-11 22:17 ` Andy Lutomirski
2024-03-11 23:10 ` Pasha Tatashin
2024-03-11 23:33 ` Thomas Gleixner
2024-03-11 23:34 ` Andy Lutomirski
2024-03-12 0:08 ` Pasha Tatashin
2024-03-12 0:23 ` Pasha Tatashin
2024-03-11 23:34 ` Dave Hansen
2024-03-11 23:41 ` Andy Lutomirski
2024-03-11 23:56 ` Nadav Amit
2024-03-12 0:02 ` Andy Lutomirski
2024-03-12 7:20 ` Nadav Amit [this message]
2024-03-12 0:53 ` Dave Hansen
2024-03-12 1:25 ` H. Peter Anvin
2024-03-12 2:16 ` Andy Lutomirski
2024-03-12 2:20 ` H. Peter Anvin
2024-03-12 21:58 ` Andi Kleen
2024-03-13 10:23 ` Thomas Gleixner
2024-03-13 13:43 ` Pasha Tatashin
2024-03-13 15:28 ` Pasha Tatashin
2024-03-13 16:12 ` Thomas Gleixner
2024-03-14 14:03 ` Pasha Tatashin
2024-03-14 18:26 ` Thomas Gleixner
2024-03-11 16:46 ` [RFC 12/14] task_stack.h: Clean-up stack_not_used() implementation Pasha Tatashin
2024-03-11 16:46 ` [RFC 13/14] task_stack.h: Add stack_not_used() support for dynamic stack Pasha Tatashin
2024-03-11 16:46 ` [RFC 14/14] fork: Dynamic Kernel Stack accounting Pasha Tatashin
2024-03-11 17:09 ` [RFC 00/14] Dynamic Kernel Stacks Mateusz Guzik
2024-03-11 18:58 ` Pasha Tatashin
2024-03-11 19:21 ` Mateusz Guzik
2024-03-11 19:55 ` Pasha Tatashin
2024-03-12 17:18 ` H. Peter Anvin
2024-03-12 19:45 ` Pasha Tatashin
2024-03-12 21:36 ` H. Peter Anvin
2024-03-14 19:05 ` Kent Overstreet
2024-03-14 19:23 ` Pasha Tatashin
2024-03-14 19:28 ` Kent Overstreet
2024-03-14 19:34 ` Pasha Tatashin
2024-03-14 19:49 ` Kent Overstreet
2024-03-12 22:18 ` David Laight
2024-03-14 19:43 ` Matthew Wilcox
2024-03-14 19:53 ` Kent Overstreet
2024-03-14 19:57 ` Matthew Wilcox
2024-03-14 19:58 ` Kent Overstreet
2024-03-15 3:13 ` Pasha Tatashin
2024-03-15 3:39 ` H. Peter Anvin
2024-03-16 19:17 ` Pasha Tatashin
2024-03-17 0:41 ` Matthew Wilcox
2024-03-17 1:32 ` Kent Overstreet
2024-03-17 14:19 ` Pasha Tatashin
2024-03-17 14:43 ` Brian Gerst
2024-03-17 16:15 ` Pasha Tatashin
2024-03-17 21:30 ` Brian Gerst
2024-03-18 14:59 ` Pasha Tatashin
2024-03-18 21:02 ` Brian Gerst
2024-03-19 14:56 ` Pasha Tatashin
2024-03-17 18:57 ` David Laight
2024-03-18 15:09 ` Pasha Tatashin
2024-03-18 15:13 ` Pasha Tatashin
2024-03-18 15:19 ` Matthew Wilcox
2024-03-18 15:30 ` Pasha Tatashin
2024-03-18 15:53 ` David Laight
2024-03-18 16:57 ` Pasha Tatashin
2024-03-18 15:38 ` David Laight
2024-03-18 17:00 ` Pasha Tatashin
2024-03-18 17:37 ` Pasha Tatashin
2024-03-15 4:17 ` H. Peter Anvin
2024-03-17 0:47 ` H. Peter Anvin
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