From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Rick P Edgecombe <rick.p.edgecombe@intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"H.J. Lu" <hjl.tools@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"andreyknvl@gmail.com" <andreyknvl@gmail.com>,
"kcc@google.com" <kcc@google.com>,
Andi Kleen <ak@linux.intel.com>,
"dvyukov@google.com" <dvyukov@google.com>,
the arch/x86 maintainers <x86@kernel.org>,
"ryabinin.a.a@gmail.com" <ryabinin.a.a@gmail.com>,
"glider@google.com" <glider@google.com>
Subject: Re: [PATCHv3 6/8] x86/mm: Provide ARCH_GET_UNTAG_MASK and ARCH_ENABLE_TAGGED_ADDR
Date: Thu, 16 Jun 2022 11:44:59 +0200 [thread overview]
Message-ID: <Yqr7mzvX1+hWM8NL@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <5d3b281f-3d8b-4bbd-9681-b226810c3e8b@www.fastmail.com>
On Sun, Jun 12, 2022 at 02:03:43PM -0700, Andy Lutomirski wrote:
> >> > > > + /* LAM has to be enabled before spawning threads */
> >> > > > + if (get_nr_threads(current) > 1)
> >> > > > + return -EBUSY;
> >> > > Does this work for vfork()? I guess the idea is that locking is
vfork() isn't the problem, the problem is that Linux allows CLONE_VM
without CLONE_THREAD. Now, mostly nobody does that these days, but it is
possible.
> get_nr_threads() is the wrong thing. Either look at mm->mm_users or
> find a way to get rid of this restriction entirely.
mm->mm_users should indeed be sufficient here.
> IMO it would not be insane to have a way to iterate over all tasks
> using an mm. But doing this for io_uring, etc might be interesting.
That has come up so often over the past 15+ years I've no idea how come
we've still not managed to actually do that ;-)
next prev parent reply other threads:[~2022-06-16 9:45 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 14:35 [PATCHv3 0/8] Linear Address Masking enabling Kirill A. Shutemov
2022-06-10 14:35 ` [PATCHv3 1/8] x86/mm: Fix CR3_ADDR_MASK Kirill A. Shutemov
2022-06-10 23:32 ` Edgecombe, Rick P
2022-06-10 14:35 ` [PATCHv3 2/8] x86: CPUID and CR3/CR4 flags for Linear Address Masking Kirill A. Shutemov
2022-06-10 14:35 ` [PATCHv3 3/8] mm: Pass down mm_struct to untagged_addr() Kirill A. Shutemov
2022-06-10 23:33 ` Edgecombe, Rick P
2022-06-17 15:27 ` Alexander Potapenko
2022-06-17 22:38 ` Kirill A. Shutemov
2022-06-10 14:35 ` [PATCHv3 4/8] x86/mm: Handle LAM on context switch Kirill A. Shutemov
2022-06-10 23:55 ` Edgecombe, Rick P
2022-06-15 15:54 ` Kirill A. Shutemov
2022-06-16 9:08 ` Peter Zijlstra
2022-06-16 16:40 ` Kirill A. Shutemov
2022-06-17 15:35 ` Alexander Potapenko
2022-06-17 22:39 ` Kirill A. Shutemov
2022-06-28 23:33 ` Andy Lutomirski
2022-06-29 0:34 ` Kirill A. Shutemov
2022-06-30 1:51 ` Andy Lutomirski
2022-06-10 14:35 ` [PATCHv3 5/8] x86/uaccess: Provide untagged_addr() and remove tags before address check Kirill A. Shutemov
2022-06-13 17:36 ` Edgecombe, Rick P
2022-06-15 16:58 ` Kirill A. Shutemov
2022-06-15 19:06 ` Edgecombe, Rick P
2022-06-16 9:30 ` Peter Zijlstra
2022-06-16 16:44 ` Kirill A. Shutemov
2022-06-17 11:36 ` Peter Zijlstra
2022-06-17 14:22 ` H.J. Lu
2022-06-17 14:28 ` Peter Zijlstra
2022-06-16 9:34 ` Peter Zijlstra
2022-06-16 10:02 ` Peter Zijlstra
2022-06-16 16:48 ` Kirill A. Shutemov
2022-06-28 23:40 ` Andy Lutomirski
2022-06-29 0:42 ` Kirill A. Shutemov
2022-06-30 2:38 ` Andy Lutomirski
2022-07-05 0:13 ` Kirill A. Shutemov
2022-06-10 14:35 ` [PATCHv3 6/8] x86/mm: Provide ARCH_GET_UNTAG_MASK and ARCH_ENABLE_TAGGED_ADDR Kirill A. Shutemov
2022-06-10 15:25 ` Edgecombe, Rick P
2022-06-10 18:04 ` Kirill A. Shutemov
2022-06-10 16:16 ` Edgecombe, Rick P
2022-06-10 18:06 ` Kirill A. Shutemov
2022-06-10 18:08 ` Edgecombe, Rick P
2022-06-10 22:18 ` Edgecombe, Rick P
2022-06-11 1:12 ` Kirill A. Shutemov
2022-06-11 2:36 ` Edgecombe, Rick P
2022-06-12 21:03 ` Andy Lutomirski
2022-06-16 9:44 ` Peter Zijlstra [this message]
2022-06-16 16:54 ` Kirill A. Shutemov
2022-06-30 2:04 ` Andy Lutomirski
2022-06-13 14:42 ` Michal Hocko
2022-06-16 17:05 ` Kirill A. Shutemov
2022-06-19 23:40 ` Kirill A. Shutemov
2022-06-16 9:39 ` Peter Zijlstra
2022-06-28 23:42 ` Andy Lutomirski
2022-06-29 0:53 ` Kirill A. Shutemov
2022-06-30 2:29 ` Andy Lutomirski
2022-07-01 15:38 ` Kirill A. Shutemov
2022-07-02 23:55 ` Andy Lutomirski
2022-07-04 13:43 ` Kirill A. Shutemov
2022-06-10 14:35 ` [PATCHv3 7/8] x86: Expose untagging mask in /proc/$PID/arch_status Kirill A. Shutemov
2022-06-10 15:24 ` Dave Hansen
2022-06-11 1:28 ` Kirill A. Shutemov
2022-06-27 12:00 ` Catalin Marinas
2022-06-10 14:35 ` [PATCHv3 OPTIONAL 8/8] x86/mm: Extend LAM to support to LAM_U48 Kirill A. Shutemov
2022-06-16 10:00 ` Peter Zijlstra
2022-06-10 20:22 ` [PATCHv3 0/8] Linear Address Masking enabling Kostya Serebryany
2022-06-16 22:52 ` Edgecombe, Rick P
2022-06-16 23:43 ` Kirill A. Shutemov
2022-06-16 23:48 ` Edgecombe, Rick P
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