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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-03-12 20:03:12 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-12 23:33:15 +0100 |
| commit | 54720df130b3e6356391ed4f8a1a024318bcae23 (patch) | |
| tree | bb15547c48f3937e6f36ffd89f0d98494c490c7e | |
| parent | Merge branch 'fib_trie_table_merge_fixes' (diff) | |
| download | linux-54720df130b3e6356391ed4f8a1a024318bcae23.tar.xz linux-54720df130b3e6356391ed4f8a1a024318bcae23.zip | |
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps
Currently, it is possible in cls_bpf to access eBPF maps only under
rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(),
the classifier would be called from __netif_receive_skb_core() under
rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via
__dev_queue_xmit().
This rcu/rcu_bh mix doesn't work together with eBPF maps as they require
soley to be called under rcu_read_lock(). eBPF maps could also be shared
among various other eBPF programs (possibly even with other eBPF program
types, f.e. tracing) and user space processes, so any context is assumed.
Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program
invocation under non-bh RCU lock variant.
Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/sched/cls_bpf.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index 243c9f225a73..5c4171c5d2bd 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -64,8 +64,10 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, { struct cls_bpf_head *head = rcu_dereference_bh(tp->root); struct cls_bpf_prog *prog; - int ret; + int ret = -1; + /* Needed here for accessing maps. */ + rcu_read_lock(); list_for_each_entry_rcu(prog, &head->plist, link) { int filter_res = BPF_PROG_RUN(prog->filter, skb); @@ -80,10 +82,11 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, if (ret < 0) continue; - return ret; + break; } + rcu_read_unlock(); - return -1; + return ret; } static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog) |