From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 6DF9CC2BC84 for ; Fri, 4 Sep 2020 08:29:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40825206CA for ; Fri, 4 Sep 2020 08:29:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729917AbgIDI3K (ORCPT ); Fri, 4 Sep 2020 04:29:10 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:42708 "EHLO fornost.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728636AbgIDI3J (ORCPT ); Fri, 4 Sep 2020 04:29:09 -0400 Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kE75j-0001TK-23; Fri, 04 Sep 2020 18:29:04 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Fri, 04 Sep 2020 18:29:03 +1000 Date: Fri, 4 Sep 2020 18:29:03 +1000 From: Herbert Xu To: Daniel Jordan Cc: Steffen Klassert , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] padata: fix possible padata_works_lock deadlock Message-ID: <20200904082902.GF1214@gondor.apana.org.au> References: <20200902170756.332491-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200902170756.332491-1-daniel.m.jordan@oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 02, 2020 at 01:07:56PM -0400, Daniel Jordan wrote: > syzbot reports, > > WARNING: inconsistent lock state > 5.9.0-rc2-syzkaller #0 Not tainted > -------------------------------- > inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. > syz-executor.0/26715 takes: > (padata_works_lock){+.?.}-{2:2}, at: padata_do_parallel kernel/padata.c:220 > {IN-SOFTIRQ-W} state was registered at: > spin_lock include/linux/spinlock.h:354 [inline] > padata_do_parallel kernel/padata.c:220 > ... > __do_softirq kernel/softirq.c:298 > ... > sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1091 > asm_sysvec_apic_timer_interrupt arch/x86/include/asm/idtentry.h:581 > > Possible unsafe locking scenario: > > CPU0 > ---- > lock(padata_works_lock); > > lock(padata_works_lock); > > padata_do_parallel() takes padata_works_lock with softirqs enabled, so a > deadlock is possible if, on the same CPU, the lock is acquired in > process context and then softirq handling done in an interrupt leads to > the same path. > > Fix by leaving softirqs disabled while do_parallel holds > padata_works_lock. > > Reported-by: syzbot+f4b9f49e38e25eb4ef52@syzkaller.appspotmail.com > Fixes: 4611ce2246889 ("padata: allocate work structures for parallel jobs from a pool") > Signed-off-by: Daniel Jordan > Cc: Herbert Xu > Cc: Steffen Klassert > Cc: linux-crypto@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > --- > kernel/padata.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Patch applied. Thanks. -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt