+ mm-disable-config_per_vma_lock-until-its-fixed.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: mm: disable CONFIG_PER_VMA_LOCK until its fixed
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-disable-config_per_vma_lock-until-its-fixed.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-disable-config_per_vma_lock-until-its-fixed.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Suren Baghdasaryan <surenb@google.com>
Subject: mm: disable CONFIG_PER_VMA_LOCK until its fixed
Date: Wed, 5 Jul 2023 18:14:00 -0700

A memory corruption was reported in [1] with bisection pointing to the
patch [2] enabling per-VMA locks for x86.  Disable per-VMA locks config to
prevent this issue until the fix is confirmed.  This is expected to be a
temporary measure.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=217624
[2] https://lore.kernel.org/all/20230227173632.3292573-30-surenb@google.com

Link: https://lkml.kernel.org/r/20230706011400.2949242-3-surenb@google.com
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/
Reported-by: Jacob Young <jacobly.alt@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624
Fixes: 0bff0aaea03e ("x86/mm: try VMA lock-based page fault handling first")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Holger Hoffstätte <holger@applied-asynchrony.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/Kconfig |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/Kconfig~mm-disable-config_per_vma_lock-until-its-fixed
+++ a/mm/Kconfig
@@ -1224,8 +1224,9 @@ config ARCH_SUPPORTS_PER_VMA_LOCK
        def_bool n
 
 config PER_VMA_LOCK
-	def_bool y
+	bool "Enable per-vma locking during page fault handling."
 	depends on ARCH_SUPPORTS_PER_VMA_LOCK && MMU && SMP
+	depends on BROKEN
 	help
 	  Allow per-vma locking during page fault handling.
 
_

Patches currently in -mm which might be from surenb@google.com are

fork-lock-vmas-of-the-parent-process-when-forking.patch
mm-disable-config_per_vma_lock-until-its-fixed.patch
swap-remove-remnants-of-polling-from-read_swap_cache_async.patch
mm-add-missing-vm_fault_result_trace-name-for-vm_fault_completed.patch
mm-drop-per-vma-lock-when-returning-vm_fault_retry-or-vm_fault_completed.patch
mm-change-folio_lock_or_retry-to-use-vm_fault-directly.patch
mm-handle-swap-page-faults-under-per-vma-lock.patch
mm-handle-userfaults-under-vma-lock.patch