mm/vmalloc: leave lazy MMU mode on PTE mapping error

commit fea18c6 upstream.

vmap_pages_pte_range() enters the lazy MMU mode, but fails to leave it in
case an error is encountered.

Link: https://lkml.kernel.org/r/20250623075721.2817094-1-agordeev@linux.ibm.com
Fixes: 2ba3e69 ("mm/vmalloc: track which page-table levels were modified")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202506132017.T1l1l6ME-lkp@intel.com/
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mm/vmalloc.c

@@ -487,6 +487,7 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
 		unsigned long end, pgprot_t prot, struct page **pages, int *nr,
 		pgtbl_mod_mask *mask)
 {
+	int err = 0;
 	pte_t *pte;
 
 	/*
@@ -500,18 +501,25 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
 	do {
 		struct page *page = pages[*nr];
 
-		if (WARN_ON(!pte_none(ptep_get(pte))))
-			return -EBUSY;
-		if (WARN_ON(!page))
-			return -ENOMEM;
-		if (WARN_ON(!pfn_valid(page_to_pfn(page))))
-			return -EINVAL;
+		if (WARN_ON(!pte_none(ptep_get(pte)))) {
+			err = -EBUSY;
+			break;
+		}
+		if (WARN_ON(!page)) {
+			err = -ENOMEM;
+			break;
+		}
+		if (WARN_ON(!pfn_valid(page_to_pfn(page)))) {
+			err = -EINVAL;
+			break;
+		}
 
 		set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
 		(*nr)++;
 	} while (pte++, addr += PAGE_SIZE, addr != end);
 	*mask |= PGTBL_PTE_MODIFIED;
-	return 0;
+
+	return err;
 }
 
 static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,