| Message ID | 20180423182939.17999.41217.stgit@john-Precision-Tower-5810 |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | BPF, a couple sockmap fixes | expand |
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index a7e0536..2389022 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -524,8 +524,6 @@ static int bpf_tcp_ingress(struct sock *sk, int apply_bytes, i = md->sg_start; do { - r->sg_data[i] = md->sg_data[i]; - size = (apply && apply_bytes < md->sg_data[i].length) ? apply_bytes : md->sg_data[i].length; @@ -536,6 +534,7 @@ static int bpf_tcp_ingress(struct sock *sk, int apply_bytes, } sk_mem_charge(sk, size); + r->sg_data[i] = md->sg_data[i]; r->sg_data[i].length = size; md->sg_data[i].length -= size; md->sg_data[i].offset += size;
In the case where the socket memory boundary is hit the redirect path returns an ENOMEM error. However, before checking for this condition the redirect scatterlist buffer is setup with a valid page and length. This is never unwound so when the buffers are released latter in the error path we do a put_page() and clear the scatterlist fields. But, because the initial error happens before completing the scatterlist buffer we end up with both the original buffer and the redirect buffer pointing to the same page resulting in duplicate put_page() calls. To fix this simply move the initial configuration of the redirect scatterlist buffer below the sock memory check. Found this while running TCP_STREAM test with netperf using Cilium. Fixes: fa246693a111 ("bpf: sockmap, BPF_F_INGRESS flag for BPF_SK_SKB_STREAM_VERDICT") Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- kernel/bpf/sockmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)