From patchwork Wed Dec 2 23:13:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 336517 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 911ADC64E7B for ; Wed, 2 Dec 2020 23:14:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F7D4221EB for ; Wed, 2 Dec 2020 23:14:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387734AbgLBXOV (ORCPT ); Wed, 2 Dec 2020 18:14:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387622AbgLBXOV (ORCPT ); Wed, 2 Dec 2020 18:14:21 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F7DDC0613D6 for ; Wed, 2 Dec 2020 15:13:35 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id c137so363952ybf.21 for ; Wed, 02 Dec 2020 15:13:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=ZFxjFlPOGRZwOnY0RO0nkySg3CsVohaI0ePFi9oHcrY=; b=szsqI7ZLY+xJ2u/4byOrY+YuFCqH/PIjA8qOolHBjTgjEKAkupUiyZ8j4v2OZ57gUj R7LJplZbv2B7JHFxpiwDx0v0VdhW4rH/iSq39aMrDaRDHpXy0DTPj44jJdKVANd6yukd /OGtLa41bdcBWFyg/xPnuo1j7w4Vyyr73QHcArGvSsAZ8v8nzVkdxYJbpx5lznzT8vN+ TmgxT2gDwPjN+jGudK8e9TWM3jDVFegBoRjMLGP+4J2HlGRw7WVxjvakdRYBCI9Cd+8A EBjq8FSvk8ydGmd4qovuTb/PnKLaNHLQk5sJyeR9lqNpewApwUSq5CTS23WwLkUIz0y+ UpHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=ZFxjFlPOGRZwOnY0RO0nkySg3CsVohaI0ePFi9oHcrY=; b=sYyKBwQyzosnSmf9nUfVZIkIR3tVNg1wdCw0HzRHUHZqdoqdeescaw++ahzeKhAEaB k2PU105CAfmFyDsMCleg4/xMLBkzK5QXCUxA2RLOeIHDkb6eJYKDQWAcTTpqC7R7F70C aszQRvGg9WQpE9i7z7q2bS3/nDHLFL2HpfT2dVfeIl+EaZDwM16ASExFd+Ot2espS3r5 6WZoV1TeXwJUhimrurPDnZQW6o/MdUhKiOx79xiwnrF8R5FlAQqT9VfrLsYFM9FKBkyo yh/NvVBPvKgXRY6Rg4M9csG6Ny/l8frC+1VYzUJKbBQg7IWENcSnekkS4pRHwnqTZrrz /umw== X-Gm-Message-State: AOAM531wCe38ai35JDImyQoOP6ATRymW3sKvX+6Be9/S69J19d/vfui8 nYtzlVWFltjmu5mzQya6xyacxP7gGnmM+QS7n+4dDX90uSjwYpnGulcNttITdv9atbV6U/A3GR1 Edl23FMGk5DK2ww70Gvix3RaMc9yXKhKmFOWafDcYNusExhGElH6xFA== X-Google-Smtp-Source: ABdhPJwexRD95gDCy4awzIG4X7TlQfJTt9TcopPQLJvcCZF3h9HVFS3ezLar8PpCNCfEGO+xsJNaM44= Sender: "sdf via sendgmr" X-Received: from sdf2.svl.corp.google.com ([2620:15c:2c4:1:7220:84ff:fe09:7732]) (user=sdf job=sendgmr) by 2002:a25:c503:: with SMTP id v3mr655637ybe.15.1606950814299; Wed, 02 Dec 2020 15:13:34 -0800 (PST) Date: Wed, 2 Dec 2020 15:13:32 -0800 Message-Id: <20201202231332.3923644-1-sdf@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH bpf-next] libbpf: cap retries in sys_bpf_prog_load From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev , Andrii Nakryiko Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org I've seen a situation, where a process that's under pprof constantly generates SIGPROF which prevents program loading indefinitely. The right thing to do probably is to disable signals in the upper layers while loading, but it still would be nice to get some error from libbpf instead of an endless loop. Let's add some small retry limit to the program loading: try loading the program 5 (arbitrary) times and give up. v2: * 10 -> 5 retires (Andrii Nakryiko) Signed-off-by: Stanislav Fomichev Acked-by: Andrii Nakryiko --- tools/lib/bpf/bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index d27e34133973..4025266d0fb0 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -67,11 +67,12 @@ static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size) { + int retries = 5; int fd; do { fd = sys_bpf(BPF_PROG_LOAD, attr, size); - } while (fd < 0 && errno == EAGAIN); + } while (fd < 0 && errno == EAGAIN && retries-- > 0); return fd; }