[PATCH AUTOSEL 5.9 001/147] powerpc/vmemmap: Fix memory leak with vmemmap list allocation failures.

Sasha Levin
2020-10-26T23:49:12Z

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

[ Upstream commit ccaea15296f9773abd43aaa17ee4b88848e4a505 ]

If we fail to allocate vmemmap list, we don't keep track of allocated
vmemmap block buf. Hence on section deactivate we skip vmemmap block
buf free. This results in memory leak.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200731113500.248306-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/mm/init_64.c | 35 ++++++++++++++++++++++++++++-------
1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 8459056cce671..2ae42c2a5cf04 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -162,16 +162,16 @@ static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
return next++;
}

-static __meminit void vmemmap_list_populate(unsigned long phys,
- unsigned long start,
- int node)
+static __meminit int vmemmap_list_populate(unsigned long phys,
+ unsigned long start,
+ int node)
{
struct vmemmap_backing *vmem_back;

vmem_back = vmemmap_list_alloc(node);
if (unlikely(!vmem_back)) {
- WARN_ON(1);
- return;
+ pr_debug("vmemap list allocation failed\n");
+ return -ENOMEM;
}

vmem_back->phys = phys;
@@ -179,6 +179,7 @@ static __meminit void vmemmap_list_populate(unsigned long phys,
vmem_back->list = vmemmap_list;

vmemmap_list = vmem_back;
+ return 0;
}

static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
@@ -199,6 +200,7 @@ static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long star
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
struct vmem_altmap *altmap)
{
+ bool altmap_alloc;
unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;

/* Align to the page size of the linear mapping. */
@@ -228,13 +230,32 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
p = vmemmap_alloc_block_buf(page_size, node, altmap);
if (!p)
pr_debug("altmap block allocation failed, falling back to system memory");
+ else
+ altmap_alloc = true;
}
- if (!p)
+ if (!p) {
p = vmemmap_alloc_block_buf(page_size, node, NULL);
+ altmap_alloc = false;
+ }
if (!p)
return -ENOMEM;

- vmemmap_list_populate(__pa(p), start, node);
+ if (vmemmap_list_populate(__pa(p), start, node)) {
+ /*
+ * If we don't populate vmemap list, we don't have
+ * the ability to free the allocated vmemmap
+ * pages in section_deactivate. Hence free them
+ * here.
+ */
+ int nr_pfns = page_size >> PAGE_SHIFT;
+ unsigned long page_order = get_order(page_size);
+
+ if (altmap_alloc)
+ vmem_altmap_free(altmap, nr_pfns);
+ else
+ free_pages((unsigned long)p, page_order);
+ return -ENOMEM;
+ }

pr_debug(" * %016lx..%016lx allocated at %p\n",
start, start + page_size, p);
--
2.25.1