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...

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: Ryan Roberts ryan.roberts@arm.com 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@arm.com 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@arm.com Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Cc: Christop Hellwig hch@infradead.org Cc: "Uladzislau Rezki (Sony)" urezki@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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@arm.com 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