* [PATCH bpf] devmap: use bpf_map_area_alloc() for allocating hash buckets
@ 2020-06-16 14:28 Toke Høiland-Jørgensen
2020-06-17 6:06 ` John Fastabend
0 siblings, 1 reply; 3+ messages in thread
From: Toke Høiland-Jørgensen @ 2020-06-16 14:28 UTC (permalink / raw)
To: daniel, ast; +Cc: Toke Høiland-Jørgensen, bpf, netdev, Xiumei Mu
Syzkaller discovered that creating a hash of type devmap_hash with a large
number of entries can hit the memory allocator limit for allocating
contiguous memory regions. There's really no reason to use kmalloc_array()
directly in the devmap code, so just switch it to the existing
bpf_map_area_alloc() function that is used elsewhere.
Reported-by: Xiumei Mu <xmu@redhat.com>
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
kernel/bpf/devmap.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 0cbb72cdaf63..5fdbc776a760 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -86,12 +86,13 @@ static DEFINE_PER_CPU(struct list_head, dev_flush_list);
static DEFINE_SPINLOCK(dev_map_lock);
static LIST_HEAD(dev_map_list);
-static struct hlist_head *dev_map_create_hash(unsigned int entries)
+static struct hlist_head *dev_map_create_hash(unsigned int entries,
+ int numa_node)
{
int i;
struct hlist_head *hash;
- hash = kmalloc_array(entries, sizeof(*hash), GFP_KERNEL);
+ hash = bpf_map_area_alloc(entries * sizeof(*hash), numa_node);
if (hash != NULL)
for (i = 0; i < entries; i++)
INIT_HLIST_HEAD(&hash[i]);
@@ -145,7 +146,8 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
return -EINVAL;
if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
- dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets);
+ dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
+ dtab->map.numa_node);
if (!dtab->dev_index_head)
goto free_charge;
@@ -232,7 +234,7 @@ static void dev_map_free(struct bpf_map *map)
}
}
- kfree(dtab->dev_index_head);
+ bpf_map_area_free(dtab->dev_index_head);
} else {
for (i = 0; i < dtab->map.max_entries; i++) {
struct bpf_dtab_netdev *dev;
--
2.27.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH bpf] devmap: use bpf_map_area_alloc() for allocating hash buckets
2020-06-16 14:28 [PATCH bpf] devmap: use bpf_map_area_alloc() for allocating hash buckets Toke Høiland-Jørgensen
@ 2020-06-17 6:06 ` John Fastabend
2020-06-17 17:03 ` Alexei Starovoitov
0 siblings, 1 reply; 3+ messages in thread
From: John Fastabend @ 2020-06-17 6:06 UTC (permalink / raw)
To: Toke Høiland-Jørgensen, daniel, ast
Cc: Toke Høiland-Jørgensen, bpf, netdev, Xiumei Mu
Toke Høiland-Jørgensen wrote:
> Syzkaller discovered that creating a hash of type devmap_hash with a large
> number of entries can hit the memory allocator limit for allocating
> contiguous memory regions. There's really no reason to use kmalloc_array()
> directly in the devmap code, so just switch it to the existing
> bpf_map_area_alloc() function that is used elsewhere.
>
> Reported-by: Xiumei Mu <xmu@redhat.com>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
> kernel/bpf/devmap.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf] devmap: use bpf_map_area_alloc() for allocating hash buckets
2020-06-17 6:06 ` John Fastabend
@ 2020-06-17 17:03 ` Alexei Starovoitov
0 siblings, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2020-06-17 17:03 UTC (permalink / raw)
To: John Fastabend
Cc: Toke Høiland-Jørgensen, Daniel Borkmann,
Alexei Starovoitov, bpf, Network Development, Xiumei Mu
On Tue, Jun 16, 2020 at 11:07 PM John Fastabend
<john.fastabend@gmail.com> wrote:
>
> Toke Høiland-Jørgensen wrote:
> > Syzkaller discovered that creating a hash of type devmap_hash with a large
> > number of entries can hit the memory allocator limit for allocating
> > contiguous memory regions. There's really no reason to use kmalloc_array()
> > directly in the devmap code, so just switch it to the existing
> > bpf_map_area_alloc() function that is used elsewhere.
> >
> > Reported-by: Xiumei Mu <xmu@redhat.com>
> > Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> > ---
> > kernel/bpf/devmap.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
Applied. Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-06-16 14:28 [PATCH bpf] devmap: use bpf_map_area_alloc() for allocating hash buckets Toke Høiland-Jørgensen
2020-06-17 6:06 ` John Fastabend
2020-06-17 17:03 ` Alexei Starovoitov
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