The patch titled
Subject: mm/gup: add missing gup_must_unshare() check to gup_huge_pgd()
has been added to the -mm mm-unstable branch. Its filename is
mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Subject: mm/gup: add missing gup_must_unshare() check to gup_huge_pgd()
Date: Sat, 6 May 2023 15:05:25 +0100
All other instances of gup_huge_pXd() perform the unshare check, so update
the PGD-specific function to do so as well.
While checking pgd_write() might seem unusual, this function already
performs such a check via pgd_access_permitted() so this is in line with
the existing implementation.
Link: https://lkml.kernel.org/r/cb971ac8dd315df97058ea69442ecc007b9a364a.1683381545.git.lstoakes@xxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/mm/gup.c~mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd
+++ a/mm/gup.c
@@ -2898,6 +2898,11 @@ static int gup_huge_pgd(pgd_t orig, pgd_
return 0;
}
+ if (!pgd_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) {
+ gup_put_folio(folio, refs, flags);
+ return 0;
+ }
+
*nr += refs;
folio_set_referenced(folio);
return 1;
_
Patches currently in -mm which might be from lstoakes@xxxxxxxxx are
mm-mmap-separate-writenotify-and-dirty-tracking-logic.patch
mm-gup-disallow-foll_longterm-gup-nonfast-writing-to-file-backed-mappings.patch
mm-gup-disallow-foll_longterm-gup-fast-writing-to-file-backed-mappings.patch
mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd.patch
