[PATCH AUTOSEL 5.1 086/141] powerpc/mm: Handle page table allocation failures

Sasha Levin
2019-07-19T04:05:32Z

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>

[ Upstream commit 2230ebf6e6dd0b7751e2921b40f6cfe34f09bb16 ]

This fixes kernel crash that arises due to not handling page table allocation
failures while allocating hugetlb page table.

Fixes: e2b3d202d1db ("powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/mm/hugetlbpage.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 9e732bb2c84a..88888e098a08 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -154,6 +154,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
+ if (!pu)
+ return NULL;
if (pshift == PUD_SHIFT)
return (pte_t *)pu;
else if (pshift > PMD_SHIFT) {
@@ -162,6 +164,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
+ if (!pm)
+ return NULL;
if (pshift == PMD_SHIFT)
/* 16MB hugepage */
return (pte_t *)pm;
@@ -178,12 +182,16 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
+ if (!pu)
+ return NULL;
if (pshift >= PUD_SHIFT) {
ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
+ if (!pm)
+ return NULL;
ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
}
--
2.20.1