Received: by 10.223.185.111 with SMTP id b44csp902581wrg; Fri, 9 Mar 2018 16:26:02 -0800 (PST) X-Google-Smtp-Source: AG47ELvQXafQTeOazjCugBaARo5dq6XDEUHMTmcBi1WNfHD/E2srOkfkkxB764Cc0cHLAFu4jDrp X-Received: by 10.99.147.72 with SMTP id w8mr294763pgm.208.1520641562246; Fri, 09 Mar 2018 16:26:02 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1520641562; cv=none; d=google.com; s=arc-20160816; b=bgDJY2xGvXERe83+EzFclh6HKS/BX/AIVLL+OdfGKTngQg8rlYOzBl67x4Sy5thSs7 xq9F0/pVtAC+zs188HwIrl7OOKt7/y76W/yh2eZ9Gn7ZhXakVYYvGfal8sksh8wOLG/y 8BSyfVhiyE8lix3oL9/V0BiyLtUzqC7UdcJU/c70+ek834N+NIRILR/9hmVD4YFPVQ/K f59ZMDLnpnsmHJPZzIiYWD4FMV7JtrruignZ0EvHeAsc6WtrkzMkUlhm4tvKfzpSQWUy ciD0XhU0T93yeBAZqJIncbQgi979QZwhPtPh3dCou5GngpydX+iukHEqhBq6BQ4sD0xB Bg/A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:user-agent:references :in-reply-to:message-id:date:subject:cc:to:from :arc-authentication-results; bh=UMhp8YryDIeu2azFNz7LL91KZ8R09OzJu+SMfXU4DDs=; b=fNBnrkL5puSRZ1BdrooLG621yEyYlv65cf6Wr7A7PnVWMlv7M+2MA+vKYfVqSHMNvK i/HsXKMXRGPOQSpiIlr5sHrvln8epJI+/YsLFKGdYt9EVHjYrO0P0wYEQwQp8I32wDlL YZzdgsAlHyvBa5mwCGeASAwnQmY4wjT/nXh6M9lHTU0scVe7thMZeBlT5N43Xbsxqbfx Qn77xZbV9VRqNE4Padnu3Uxn3hbT7Yc1Eb3BowKVf3kJaJX6fdm2ZdxjripOr5H8UiOk KYI7a7mp4i626UYh9uTlB78szYheTTPUuKWHpmJlmgqtSfxoL0QWHzOKMOwafqCHRMqp 0UHQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f11si1468994pgs.782.2018.03.09.16.25.47; Fri, 09 Mar 2018 16:26:02 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934249AbeCJAYi (ORCPT + 99 others); Fri, 9 Mar 2018 19:24:38 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41226 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934185AbeCJAXu (ORCPT ); Fri, 9 Mar 2018 19:23:50 -0500 Received: from localhost (unknown [185.236.200.248]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id C2A59BBC; Sat, 10 Mar 2018 00:23:49 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Eric Dumazet" , syzbot , Daniel Borkmann , Eric Dumazet Subject: [PATCH 4.15 06/11] bpf: add schedule points in percpu arrays management Date: Fri, 9 Mar 2018 16:19:20 -0800 Message-Id: <20180310001834.899044596@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180310001834.560857664@linuxfoundation.org> References: <20180310001834.560857664@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ upstream commit 32fff239de37ef226d5b66329dd133f64d63b22d ] syszbot managed to trigger RCU detected stalls in bpf_array_free_percpu() It takes time to allocate a huge percpu map, but even more time to free it. Since we run in process context, use cond_resched() to yield cpu if needed. Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/arraymap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -26,8 +26,10 @@ static void bpf_array_free_percpu(struct { int i; - for (i = 0; i < array->map.max_entries; i++) + for (i = 0; i < array->map.max_entries; i++) { free_percpu(array->pptrs[i]); + cond_resched(); + } } static int bpf_array_alloc_percpu(struct bpf_array *array) @@ -43,6 +45,7 @@ static int bpf_array_alloc_percpu(struct return -ENOMEM; } array->pptrs[i] = ptr; + cond_resched(); } return 0;