[PATCH v4 3/8] s390/mm: Use lock_mm_and_find_vma() in do_secure_storage_access()

[Heiko Carstens <hca@linux.ibm.com>]

do_secure_storage_access() uses find_vma() without verifying that the
faulting address is within the returned vma. Add this missing check by
converting to lock_mm_and_find_vma().

This is not a critical fix, since the worst that could happen is a
WARN_ON_ONCE() in folio_walk_start().

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260717093904.E4A421F00A3E@smtp.kernel.org/
Link: https://lore.kernel.org/all/20260717093904.E4A421F00A3E@smtp.kernel.org/
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/mm/fault.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 2839d7a64401..f150d97cac2e 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -455,10 +455,9 @@ void do_secure_storage_access(struct pt_regs *regs)
 	} else {
 		if (faulthandler_disabled() || !mm)
 			return handle_fault_error_nolock(regs, 0);
-		mmap_read_lock(mm);
-		vma = find_vma(mm, addr);
+		vma = lock_mm_and_find_vma(mm, addr, regs);
 		if (!vma)
-			return handle_fault_error(regs, SEGV_MAPERR);
+			return handle_fault_error_nolock(regs, SEGV_MAPERR);
 		folio = folio_walk_start(&fw, vma, addr, 0);
 		if (!folio) {
 			mmap_read_unlock(mm);
-- 
2.53.0