From f0dce1d9b7c81fc3dc9d0cc0bc7ef9b3eae22584 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 18 Aug 2021 16:52:15 -0700 Subject: bpf: Use kvmalloc for map values in syscall Use kvmalloc/kvfree for temporary value when manipulating a map via syscall. kmalloc might not be sufficient for percpu maps where the value is big (and further multiplied by hundreds of CPUs). Can be reproduced with netcnt test on qemu with "-smp 255". Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210818235216.1159202-1-sdf@google.com --- kernel/bpf/syscall.c | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) (limited to 'kernel/bpf/syscall.c') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7420e1334ab2..075f650d297a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1076,7 +1076,7 @@ static int map_lookup_elem(union bpf_attr *attr) value_size = bpf_map_value_size(map); err = -ENOMEM; - value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); + value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); if (!value) goto free_key; @@ -1091,7 +1091,7 @@ static int map_lookup_elem(union bpf_attr *attr) err = 0; free_value: - kfree(value); + kvfree(value); free_key: kfree(key); err_put: @@ -1137,16 +1137,10 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) goto err_put; } - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || - map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) - value_size = round_up(map->value_size, 8) * num_possible_cpus(); - else - value_size = map->value_size; + value_size = bpf_map_value_size(map); err = -ENOMEM; - value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); + value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); if (!value) goto free_key; @@ -1157,7 +1151,7 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) err = bpf_map_update_value(map, f, key, value, attr->flags); free_value: - kfree(value); + kvfree(value); free_key: kfree(key); err_put: @@ -1367,7 +1361,7 @@ int generic_map_update_batch(struct bpf_map *map, if (!key) return -ENOMEM; - value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); + value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); if (!value) { kfree(key); return -ENOMEM; @@ -1390,7 +1384,7 @@ int generic_map_update_batch(struct bpf_map *map, if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) err = -EFAULT; - kfree(value); + kvfree(value); kfree(key); return err; } @@ -1429,7 +1423,7 @@ int generic_map_lookup_batch(struct bpf_map *map, if (!buf_prevkey) return -ENOMEM; - buf = kmalloc(map->key_size + value_size, GFP_USER | __GFP_NOWARN); + buf = kvmalloc(map->key_size + value_size, GFP_USER | __GFP_NOWARN); if (!buf) { kfree(buf_prevkey); return -ENOMEM; @@ -1492,7 +1486,7 @@ int generic_map_lookup_batch(struct bpf_map *map, free_buf: kfree(buf_prevkey); - kfree(buf); + kvfree(buf); return err; } @@ -1547,7 +1541,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) value_size = bpf_map_value_size(map); err = -ENOMEM; - value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); + value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); if (!value) goto free_key; @@ -1579,7 +1573,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) err = 0; free_value: - kfree(value); + kvfree(value); free_key: kfree(key); err_put: -- cgit v1.2.3-58-ga151