From 2de7852fe9096e92c5f10faa472550a2a7121cea Mon Sep 17 00:00:00 2001
From: Peng Fan <peng.fan@nxp.com>
Date: Wed, 20 Feb 2019 13:32:55 +0000
Subject: [PATCH 1/2] percpu: use nr_groups as check condition
group_cnt array is defined with NR_CPUS entries, but normally
nr_groups will not reach up to NR_CPUS. So there is no issue
to the current code.
Checking other parts of pcpu_build_alloc_info, use nr_groups as
check condition, so make it consistent to use 'group < nr_groups'
as for loop check. In case we do have nr_groups equals with NR_CPUS,
we could also avoid memory access out of bounds.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
mm/percpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/percpu.c b/mm/percpu.c
index db86282fd024..c5c750781628 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2384,7 +2384,7 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
ai->atom_size = atom_size;
ai->alloc_size = alloc_size;
- for (group = 0, unit = 0; group_cnt[group]; group++) {
+ for (group = 0, unit = 0; group < nr_groups; group++) {
struct pcpu_group_info *gi = &ai->groups[group];
/*
From 1b046b445c0f856c3c1eed38a348bd87cc2dc730 Mon Sep 17 00:00:00 2001
From: Peng Fan <peng.fan@nxp.com>
Date: Sun, 24 Feb 2019 13:13:50 +0000
Subject: [PATCH 2/2] percpu: km: no need to consider pcpu_group_offsets[0]
percpu-km is used on UP systems which only has one group,
so the group offset will be always 0, there is no need
to subtract pcpu_group_offsets[0] when assigning chunk->base_addr
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
mm/percpu-km.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index 0f643dc2dc65..b68d5df14731 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -67,7 +67,7 @@ static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
pcpu_set_page_chunk(nth_page(pages, i), chunk);
chunk->data = pages;
- chunk->base_addr = page_address(pages) - pcpu_group_offsets[0];
+ chunk->base_addr = page_address(pages);
spin_lock_irqsave(&pcpu_lock, flags);
pcpu_chunk_populated(chunk, 0, nr_pages, false);