From: Andrew Morton <akpm@linux-foundation.org>
To: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Hugh Dickins <hughd@google.com>,
Nicholas Piggin <npiggin@gmail.com>,
Guenter Roeck <linux@roeck-us.net>,
Juergen Gross <jgross@suse.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kasan-dev@googlegroups.com, sparclinux@vger.kernel.org,
xen-devel@lists.xenproject.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2 3/3] mm: Protect kernel pgtables in apply_to_pte_range()
Date: Thu, 10 Apr 2025 15:47:44 -0700 [thread overview]
Message-ID: <20250410154744.44991b2abe5f842e34320917@linux-foundation.org> (raw)
In-Reply-To: <Z/fauW5hDSt+ciwr@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com>
On Thu, 10 Apr 2025 16:50:33 +0200 Alexander Gordeev <agordeev@linux.ibm.com> wrote:
> On Tue, Apr 08, 2025 at 06:07:32PM +0200, Alexander Gordeev wrote:
>
> Hi Andrew,
>
> > The lazy MMU mode can only be entered and left under the protection
> > of the page table locks for all page tables which may be modified.
>
> Heiko Carstens noticed that the above claim is not valid, since
> v6.15-rc1 commit 691ee97e1a9d ("mm: fix lazy mmu docs and usage"),
> which restates it to:
>
> "In the general case, no lock is guaranteed to be held between entry and exit
> of the lazy mode. So the implementation must assume preemption may be enabled"
>
> That effectively invalidates this patch, so it needs to be dropped.
>
> Patch 2 still could be fine, except -stable and Fixes tags and it does
> not need to aim 6.15-rcX. Do you want me to repost it?
I dropped the whole series - let's start again.
prev parent reply other threads:[~2025-04-10 22:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-08 16:07 [PATCH v2 0/3] mm: Fix apply_to_pte_range() vs lazy MMU mode Alexander Gordeev
2025-04-08 16:07 ` [PATCH v2 1/3] kasan: Avoid sleepable page allocation from atomic context Alexander Gordeev
2025-04-09 14:10 ` Andrey Ryabinin
2025-04-09 14:25 ` Alexander Gordeev
2025-04-09 14:56 ` Andrey Ryabinin
2025-04-10 15:18 ` Alexander Gordeev
2025-04-08 16:07 ` [PATCH v2 2/3] mm: Cleanup apply_to_pte_range() routine Alexander Gordeev
2025-04-08 16:07 ` [PATCH v2 3/3] mm: Protect kernel pgtables in apply_to_pte_range() Alexander Gordeev
2025-04-10 14:50 ` Alexander Gordeev
2025-04-10 22:47 ` Andrew Morton [this message]
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