From: Alexei Starovoitov ast@kernel.org
mainline inclusion from mainline-5.12-rc1 commit 638e4b825d523bed7a55e776c153049fb7716466 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Since sleepable programs are now executing under migrate_disable the per-cpu maps are safe to use. The map-in-map were ok to use in sleepable from the time sleepable progs were introduced.
Note that non-preallocated maps are still not safe, since there is no rcu_read_lock yet in sleepable programs and dynamically allocated map elements are relying on rcu protection. The sleepable programs have rcu_read_lock_trace instead. That limitation will be addresses in the future.
Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Andrii Nakryiko andrii@kernel.org Acked-by: KP Singh kpsingh@kernel.org Link: https://lore.kernel.org/bpf/20210210033634.62081-9-alexei.starovoitov@gmail.... (cherry picked from commit 638e4b825d523bed7a55e776c153049fb7716466) Signed-off-by: Wang Yufen wangyufen@huawei.com --- kernel/bpf/hashtab.c | 4 ++-- kernel/bpf/verifier.c | 7 ++++++- 2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index a61c40dd5976..53e641ff3b9e 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1164,7 +1164,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key, /* unknown flags */ return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
key_size = map->key_size;
@@ -1218,7 +1218,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, /* unknown flags */ return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
key_size = map->key_size;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2d6dd6c3a59a..606790c02cf4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10462,9 +10462,14 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_HASH: case BPF_MAP_TYPE_LRU_HASH: case BPF_MAP_TYPE_ARRAY: + case BPF_MAP_TYPE_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_ARRAY: + case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_ARRAY_OF_MAPS: + case BPF_MAP_TYPE_HASH_OF_MAPS: if (!is_preallocated_map(map)) { verbose(env, - "Sleepable programs can only use preallocated hash maps\n"); + "Sleepable programs can only use preallocated maps\n"); return -EINVAL; } break;