From: Vasily Gorbik <gor@linux.ibm.com>
Date: Fri, 21 Aug 2020 16:27:36 +0000 (+0200)
Subject: s390/vmem: fix vmem_add_range for 4-level paging
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=bffc2f7aa96343f91931272d7a8a2d8d925e1ab2;p=linux.git

s390/vmem: fix vmem_add_range for 4-level paging

The kernel currently crashes if 4-level paging is used. Add missing
p4d_populate for just allocated pud entry.

Fixes: 3e0d3e408e63 ("s390/vmem: consolidate vmem_add_range() and vmem_remove_range()")
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 1aed1a4dfc2d6..eddf71c22875e 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -402,6 +402,7 @@ static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
 			pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
 			if (!pud)
 				goto out;
+			p4d_populate(&init_mm, p4d, pud);
 		}
 		ret = modify_pud_table(p4d, addr, next, add, direct);
 		if (ret)