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

[Alexander Gordeev]

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

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/r/202506132017.T1l1l6ME-lkp@xxxxxxxxx/
Fixes: 44562c71e2cf ("mm/vmalloc: Enter lazy mmu mode while manipulating vmalloc ptes")
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
---
 mm/vmalloc.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ab986dd09b6a..6dbcdceecae1 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -514,6 +514,7 @@ 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;
 
 	/*
@@ -530,12 +531,18 @@ 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)++;
@@ -543,7 +550,8 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
 
 	arch_leave_lazy_mmu_mode();
 	*mask |= PGTBL_PTE_MODIFIED;
-	return 0;
+
+	return err;
 }
 
 static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,
-- 
2.48.1