Commit 3685024e authored Feb 26, 2025 by Ryan Roberts Committed by Andrew Morton Mar 05, 2025

mm: don't skip arch_sync_kernel_mappings() in error paths

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: 2ba3e694 ("mm/vmalloc: track which page-table levels were modified")
Fixes: 0c95cba4 ("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>

parent adae46ac

mm/memory.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -3051,8 +3051,10 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
		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;

mm/vmalloc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -586,13 +586,13 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
		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;
		}

		/*