The patch titled
Subject: mm: don't skip arch_sync_kernel_mappings() in error paths
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-dont-skip-arch_sync_kernel_mappings-in-error-paths.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-dont-skip-arch_sync_kernel_mappings-in-error-paths.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Ryan Roberts <ryan.roberts@xxxxxxx>
Subject: mm: don't skip arch_sync_kernel_mappings() in error paths
Date: Wed, 26 Feb 2025 12:16:09 +0000
Fix callers that previously skipped calling arch_sync_kernel_mappings() if
an error occurred during a pgtable update. The call is still required to
sync any pgtable updates that may have occurred prior to hitting the error
condition.
These are theoretical bugs discovered during code review.
Link: https://lkml.kernel.org/r/20250226121610.2401743-1-ryan.roberts@xxxxxxx
Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
Fixes: 0c95cba49255 ("mm: apply_to_pte_range warn and fail if a large pte is encountered")
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christop Hellwig <hch@xxxxxxxxxxxxx>
Cc: "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 6 ++++--
mm/vmalloc.c | 4 ++--
2 files changed, 6 insertions(+), 4 deletions(-)
--- a/mm/memory.c~mm-dont-skip-arch_sync_kernel_mappings-in-error-paths
+++ a/mm/memory.c
@@ -3051,8 +3051,10 @@ static int __apply_to_page_range(struct
next = pgd_addr_end(addr, end);
if (pgd_none(*pgd) && !create)
continue;
- if (WARN_ON_ONCE(pgd_leaf(*pgd)))
- return -EINVAL;
+ if (WARN_ON_ONCE(pgd_leaf(*pgd))) {
+ err = -EINVAL;
+ break;
+ }
if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) {
if (!create)
continue;
--- a/mm/vmalloc.c~mm-dont-skip-arch_sync_kernel_mappings-in-error-paths
+++ a/mm/vmalloc.c
@@ -586,13 +586,13 @@ static int vmap_small_pages_range_noflus
mask |= PGTBL_PGD_MODIFIED;
err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
if (err)
- return err;
+ break;
} while (pgd++, addr = next, addr != end);
if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
arch_sync_kernel_mappings(start, end);
- return 0;
+ return err;
}
/*
_
Patches currently in -mm which might be from ryan.roberts@xxxxxxx are
mm-dont-skip-arch_sync_kernel_mappings-in-error-paths.patch
mm-ioremap-pass-pgprot_t-to-ioremap_prot-instead-of-unsigned-long.patch
