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authorDaniel Borkmann <daniel@iogearbox.net>2015-03-12 20:03:12 +0100
committerDavid S. Miller <davem@davemloft.net>2015-03-12 18:33:15 -0400
commit54720df130b3e6356391ed4f8a1a024318bcae23 (patch)
treebb15547c48f3937e6f36ffd89f0d98494c490c7e /net/sched/cls_bpf.c
parent06741d055bb1a630f793e36a486a209698ea672b (diff)
downloadlinux-54720df130b3e6356391ed4f8a1a024318bcae23.tar.bz2
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>
Diffstat (limited to 'net/sched/cls_bpf.c')
-rw-r--r--net/sched/cls_bpf.c9
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)