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

commit 3685024edd270f7c791f993157d65d3c928f3d6e upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index d322ddfe6791675c232734e8135dc51523d6b42d..ec86e50f3f861356fcc5f6c965d33f4741c888c1 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2957,8 +2957,10 @@ 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;

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3f9255dfacb0c14f9e35f6208b3025e5dc0278a5..fd70a7cd1c8fa8911bfc843368441b31ba072f54 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -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;
 }
 
 /*