* [PATCH] bpf: grab rcu read lock for bpf_percpu_hash_update
@ 2016-02-19 2:56 Sasha Levin
2016-02-19 3:12 ` Alexei Starovoitov
0 siblings, 1 reply; 2+ messages in thread
From: Sasha Levin @ 2016-02-19 2:56 UTC (permalink / raw)
To: ast; +Cc: netdev, linux-kernel, davem, Sasha Levin
bpf_percpu_hash_update() expects rcu lock to be held and warns if it's not,
which pointed out a missing rcu read lock.
Fixes: 15a07b338 ("bpf: add lookup/update support for per-cpu hash and array maps")
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
kernel/bpf/syscall.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c95a753..94324b8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -348,7 +348,9 @@ static int map_update_elem(union bpf_attr *attr)
goto free_value;
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
+ rcu_read_lock();
err = bpf_percpu_hash_update(map, key, value, attr->flags);
+ rcu_read_unlock();
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
err = bpf_percpu_array_update(map, key, value, attr->flags);
} else {
--
1.7.10.4
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] bpf: grab rcu read lock for bpf_percpu_hash_update
2016-02-19 2:56 [PATCH] bpf: grab rcu read lock for bpf_percpu_hash_update Sasha Levin
@ 2016-02-19 3:12 ` Alexei Starovoitov
0 siblings, 0 replies; 2+ messages in thread
From: Alexei Starovoitov @ 2016-02-19 3:12 UTC (permalink / raw)
To: Sasha Levin; +Cc: ast, netdev, linux-kernel, davem
On Thu, Feb 18, 2016 at 09:56:22PM -0500, Sasha Levin wrote:
> bpf_percpu_hash_update() expects rcu lock to be held and warns if it's not,
> which pointed out a missing rcu read lock.
>
> Fixes: 15a07b338 ("bpf: add lookup/update support for per-cpu hash and array maps")
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> ---
> kernel/bpf/syscall.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index c95a753..94324b8 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -348,7 +348,9 @@ static int map_update_elem(union bpf_attr *attr)
> goto free_value;
>
> if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
> + rcu_read_lock();
> err = bpf_percpu_hash_update(map, key, value, attr->flags);
> + rcu_read_unlock();
good catch. thanks, but could you add rcu_read_lock/unlock
inside bpf_percpu_hash_update() instead... to match what
bpf_percpu_hash_copy/bpf_percpu_array_update/bpf_percpu_array_copy are doing.
Otherwise it's inconsistent.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2016-02-19 2:56 [PATCH] bpf: grab rcu read lock for bpf_percpu_hash_update Sasha Levin
2016-02-19 3:12 ` Alexei Starovoitov
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