From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1715849-1520641504-2-15387379203092241353 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES enro, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520641503; b=i/RVO7y8Ol91oTqHg2DaGNcWGlqxENHuJywqKrRfhsd2Q4G DZBlFTNbn0HThoZwmv92iidkkgC8KUd+jF6a/yoJ7S1az7lPvje/VVlkwI/31FG6 bhY7iYFXdyXSyCjZgGpQTI1NDFrXL+REkY3Ik91U4IAmPUQRkLs8aeNci6JlFRL5 iRI2pDvdpeWvxNAwki9oQb4/MkU4o5KHjY8mXjouwwZRAFqV2/Q5puuhvz2Dv8c4 xrelHYEaWmB2rFdnLp96uXUKLZq17wG3wGF6WssAPZqPDXG2Ik0Vm17s33KjFr/o qgxO8dENvvWdfZHzpaHocowPPN/kYJFRKU2IQrw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1520641503; bh=UMhp8YryDIeu2azFNz7LL91KZ8 R09OzJu+SMfXU4DDs=; b=UxDPu5vhdBJ0d440jhiBmDY6COv1Jdread/N5hANmi uh0HgKkLCGqvSeR3+jb/DMh5eOqYYnw/94nukSaIvCMVUyvn5tOSdHsfFVgKTd0I +995JHmrVwDWVu9alvU1U6RNV5d7c2bINorKKhRG1O8ment5TOsbu5zVVVQOAYLH hpi35TvMmYt78MIPcN7iAp9TVzv9gkX1z+NXLOPQifkI60MuJ+Aqci0N8pOGqw3/ viFxvIP5MOo9bH4X2mvnn6yt8Y6pKR974Dz4SLaezLz1GgkUplZZAum7JpZPrw/A ewY8W3OPUR5EArnLdecBNBFP6r0J/E4OIhjpWXcfs2nw== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933657AbeCJAYg (ORCPT ); Fri, 9 Mar 2018 19:24:36 -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 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: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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;