The patch titled
Subject: mm: extend max struct page size for kmsan
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-extend-max-struct-page-size-for-kmsan.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-extend-max-struct-page-size-for-kmsan.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: Arnd Bergmann <arnd@xxxxxxxx>
Subject: mm: extend max struct page size for kmsan
Date: Mon, 30 Jan 2023 14:07:26 +0100
After x86 enabled support for KMSAN, it has become possible to have larger
'struct page' than was expected when commit 5470dea49f53 ("mm: use
mm_zero_struct_page from SPARC on all 64b architectures") was merged:
include/linux/mm.h:156:10: warning: no case matching constant switch condition '96'
switch (sizeof(struct page)) {
Extend the maximum accordingly.
Link: https://lkml.kernel.org/r/20230130130739.563628-1-arnd@xxxxxxxxxx
Fixes: 5470dea49f53 ("mm: use mm_zero_struct_page from SPARC on all 64b architectures")
Fixes: 4ca8cc8d1bbe ("x86: kmsan: enable KMSAN builds for x86")
Fixes: f80be4571b19 ("kmsan: add KMSAN runtime core")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alex Sierra <alex.sierra@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/include/linux/mm.h~mm-extend-max-struct-page-size-for-kmsan
+++ a/include/linux/mm.h
@@ -137,7 +137,7 @@ extern int mmap_rnd_compat_bits __read_m
* define their own version of this macro in <asm/pgtable.h>
*/
#if BITS_PER_LONG == 64
-/* This function must be updated when the size of struct page grows above 80
+/* This function must be updated when the size of struct page grows above 96
* or reduces below 56. The idea that compiler optimizes out switch()
* statement, and only leaves move/store instructions. Also the compiler can
* combine write statements if they are both assignments and can be reordered,
@@ -148,12 +148,18 @@ static inline void __mm_zero_struct_page
{
unsigned long *_pp = (void *)page;
- /* Check that struct page is either 56, 64, 72, or 80 bytes */
+ /* Check that struct page is either 56, 64, 72, 80, 88 or 96 bytes */
BUILD_BUG_ON(sizeof(struct page) & 7);
BUILD_BUG_ON(sizeof(struct page) < 56);
- BUILD_BUG_ON(sizeof(struct page) > 80);
+ BUILD_BUG_ON(sizeof(struct page) > 96);
switch (sizeof(struct page)) {
+ case 96:
+ _pp[11] = 0;
+ fallthrough;
+ case 88:
+ _pp[10] = 0;
+ fallthrough;
case 80:
_pp[9] = 0;
fallthrough;
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
zsmalloc-fix-a-race-with-deferred_handles-storing-fix.patch
mm-extend-max-struct-page-size-for-kmsan.patch
mm-hugetlb-convert-get_hwpoison_huge_page-to-folios-fix.patch
