From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: [bpf PATCH v2 0/3] sockmap error path fixes Date: Wed, 02 May 2018 13:50:14 -0700 Message-ID: <20180502204748.12776.80509.stgit@john-Precision-Tower-5810> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: borkmann@iogearbox.net, ast@kernel.org Return-path: Received: from [184.63.162.180] ([184.63.162.180]:43658 "EHLO john-Precision-Tower-5810" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750939AbeEBUuS (ORCPT ); Wed, 2 May 2018 16:50:18 -0400 Sender: netdev-owner@vger.kernel.org List-ID: When I added the test_sockmap to selftests I mistakenly changed the test logic a bit. The result of this was on redirect cases we ended up choosing the wrong sock from the BPF program and ended up sending to a socket that had no receive handler. The result was the actual receive handler, running on a different socket, is timing out and closing the socket. This results in errors (-EPIPE to be specific) on the sending side. Typically happening if the sender does not complete the send before the receive side times out. So depending on timing and the size of the send we may get errors. This exposed some bugs in the sockmap error path handling. This series fixes the errors. The primary issue is we did not do proper memory accounting in these cases which resulted in missing a sk_mem_uncharge(). This happened in the redirect path and in one case on the normal send path. See the three patches for the details. The other take-away from this is we need to fix the test_sockmap and also add more negative test cases. That will happen in bpf-next. Finally, I tested this using the existing test_sockmap program, the older sockmap sample test script, and a few real use cases with Cilium. All of these seem to be in working correctly. v2: fix compiler warning, drop iterator variable 'i' that is no longer used in patch 3. --- John Fastabend (3): bpf: sockmap, fix scatterlist update on error path in send with apply bpf: sockmap, zero sg_size on error when buffer is released bpf: sockmap, fix error handling in redirect failures kernel/bpf/sockmap.c | 48 ++++++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 22 deletions(-)