[PATCH 5.8 251/464] powerpc/mm/radix: Free PUD table when freeing pagetable

From: Greg Kroah-Hartman
Date: Mon Aug 17 2020 - 11:35:04 EST


From: Bharata B Rao <bharata@xxxxxxxxxxxxx>

[ Upstream commit 9ce8853b4a735c8115f55ac0e9c2b27a4c8f80b5 ]

remove_pagetable() isn't freeing PUD table. This causes memory
leak during memory unplug. Fix this.

Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
Signed-off-by: Bharata B Rao <bharata@xxxxxxxxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200709131925.922266-3-aneesh.kumar@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/powerpc/mm/book3s64/radix_pgtable.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index bb00e0cba1195..c2989c1718839 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -700,6 +700,21 @@ static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
pud_clear(pud);
}

+static void free_pud_table(pud_t *pud_start, p4d_t *p4d)
+{
+ pud_t *pud;
+ int i;
+
+ for (i = 0; i < PTRS_PER_PUD; i++) {
+ pud = pud_start + i;
+ if (!pud_none(*pud))
+ return;
+ }
+
+ pud_free(&init_mm, pud_start);
+ p4d_clear(p4d);
+}
+
struct change_mapping_params {
pte_t *pte;
unsigned long start;
@@ -874,6 +889,7 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end)

pud_base = (pud_t *)p4d_page_vaddr(*p4d);
remove_pud_table(pud_base, addr, next);
+ free_pud_table(pud_base, p4d);
}

spin_unlock(&init_mm.page_table_lock);
--
2.25.1