[to-be-updated] mm-secretmem-disable-under-highmem.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm/secretmem: disable under HIGHMEM
has been removed from the -mm tree.  Its filename was
     mm-secretmem-disable-under-highmem.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Brendan Jackman <jackmanb@google.com>
Subject: mm/secretmem: disable under HIGHMEM
Date: Fri, 03 Jul 2026 14:48:26 +0000

secretmem_fault() allocates a folio with GFP_HIGHUSER and then calls
set_direct_map_valid_noflush() without checking folio_test_highmem(). 
This causes a warning and process crash (vibe-coded reproducer in Link
below):

Su[   30.071284] ------------[ cut here ]------------
ccessfully allocated and mapped 2097152000 bytes at 0x3a449000
Populating memor[   30.074614] CPA: called for zero pte. vaddr = 0 cpa->vaddr = 0
y...
[   30.078636] WARNING: arch/x86/mm/pat/set_memory.c:1840 at __cpa_process_fault+0x34d/0x360, CPU#5: allocate_secret/570
[   30.084789] CPU: 5 UID: 0 PID: 570 Comm: allocate_secret Not tainted 7.1.0-14063-g4edcdefd4083-dirty #10 PREEMPTLAZY
[   30.090937] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[   30.097543] EIP: __cpa_process_fault+0x34d/0x360
[   30.100514] Code: ff ff 85 c0 0f 89 7d fe ff ff e9 3d fe ff ff 8b 03 8b 00 c7 04 24 c8 ff 64 c1 89 44 24 08 8b 45 e8 89 44 24 04 e8 53 7
a 00 00 <0f> 0b c7 45 f0 f2 ff ff ff e9 fc fc ff ff 90 8d 74 26 00 55 25 00
[   30.110829] EAX: 00000000 EBX: f64afe98 ECX: 00000000 EDX: 00000000
[   30.114799] ESI: 00000000 EDI: f64afe98 EBP: f64afe04 ESP: f64afdcc
[   30.118785] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010246
[   30.123020] CR0: 80050033 CR2: 46c48ffc CR3: 038c8000 CR4: 00000690
[   30.127010] Call Trace:
[   30.129078]  __change_page_attr_set_clr+0x5e7/0x870
[   30.132275]  ? console_unlock+0x99/0x130
[   30.135069]  ? irq_work_queue+0x36/0x70
[   30.137853]  ? page_address+0xd3/0xf0
[   30.140421]  set_direct_map_invalid_noflush+0x52/0x60
[   30.143782]  secretmem_fault+0x128/0x210
[   30.146560]  __do_fault+0x25/0x90
[   30.149053]  handle_mm_fault+0x6d1/0xcb0
[   30.151759]  exc_page_fault+0x135/0x3b0
[   30.154487]  ? doublefault_shim+0x150/0x150
[   30.157416]  handle_exception+0x130/0x130
[   30.160137] EIP: 0x804d29f
[   30.162307] Code: 89 54 08 e1 89 54 08 e5 89 54 08 e9 89 54 08 ed c3 0f b6 44 24 08 89 7c 24 0c 69 c0 01 01 01 01 8b 7c 24 04 f7 c7 0f 0
0 00 00 <89> 44 0f fc 75 0e c1 e9 02 f3 ab 8b 44 24 04 8b 7c 24 0c c3 31 d2
[   30.172936] EAX: 5a5a5a5a EBX: 00000000 ECX: 0c800000 EDX: 3a449000
[   30.176927] ESI: 00000000 EDI: 3a449000 EBP: bfbbae18 ESP: bfbbadac
[   30.180897] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00010246
[   30.185161]  ? doublefault_shim+0x150/0x150
[   30.187979] ---[ end trace 0000000000000000 ]---
Bus error                  (core dumped) ./allocate_secret_i686 2000M

The equivalent bug was pointed out by a local Sashiko instance on
https://lore.kernel.org/all/20260410151746.61150-3-kalyazin@amazon.com/

This hasn't been reproduced on older kernel versions but from code
inspection the bug seems to go back to the original introduction in commit
1507f51255c9f ("mm: introduce memfd_secret system call to create "secret"
memory areas").  If this configuration has always been broken, dropping
support is not really a regression, so do that.

Link: https://github.com/bjackman/limmat-kernel-nix/commit/7b2acba2d3a5ef01400d493a155beb1d135b6bb5
Link: https://lore.kernel.org/20260703-secretmem-highmem-v1-1-30d5ff944664@google.com
Fixes: 1507f51255c9 ("mm: introduce memfd_secret system call to create "secret" memory areas")
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/mm/Kconfig~mm-secretmem-disable-under-highmem
+++ a/mm/Kconfig
@@ -1356,7 +1356,7 @@ config MEMFD_CREATE
 config SECRETMEM
 	default y
 	bool "Enable memfd_secret() system call" if EXPERT
-	depends on ARCH_HAS_SET_DIRECT_MAP
+	depends on ARCH_HAS_SET_DIRECT_MAP && !HIGHMEM
 	help
 	  Enable the memfd_secret() system call with the ability to create
 	  memory areas visible only in the context of the owning process and
_

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

mm-page_alloc-drop-flag-conversion-optimisation.patch
mm-page_alloc-rename-alloc_trylock-alloc_nolock.patch
mm-page_alloc-some-renames-to-clarify-alloc_flags-scopes.patch
mm-name-some-args-in-a-function-declaration.patch
mm-split-out-internal-page_alloch.patch
mm-page_alloc-unify-__alloc_frozen_pages_noprof.patch
mm-page_alloc-relax-gfp-warn-in-nolock-allocs.patch
mm-move-some-stuff-to-mm-page_alloch.patch
perf-x86-intel-use-higher-level-allocator-api.patch
kvm-vmx-use-higher-level-allocator-api.patch
x86-virt-use-higher-level-allocator-api.patch
sgi-xp-use-higher-level-allocator-api.patch
net-funeth-switch-to-higher-level-allocator-api.patch
mm-remove-__alloc_pages_node.patch
mm-move-__alloc_pages-to-mm-page_alloch.patch
mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch
mm-page_alloc-drop-alloc_flags-arg-from-alloc_flags_cma.patch
mm-factor-out-can_spin_trylock.patch
mm-page_alloc-dont-spin_trylock-in-nmi-on-up.patch
mm-page_alloc-dont-spin_trylock-when-disallowed-in-free_one_page.patch
mm-page_alloc-rename-fpi_trylock-fpi_nolock.patch
cgroup-cpuset-update-some-comments-about-the-page-allocator.patch
mm-page_alloc-fixup-alloc_pages_nolock_noprof-comment.patch
mm-page_alloc-remove-a-couple-of-vm_bug_onst.patch