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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 D0072C4CEC9 for ; Tue, 17 Sep 2019 07:16:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9EA0521670 for ; Tue, 17 Sep 2019 07:16:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9EA0521670 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4820C6B0006; Tue, 17 Sep 2019 03:16:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4320E6B0008; Tue, 17 Sep 2019 03:16:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 346C56B000A; Tue, 17 Sep 2019 03:16:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id 0C27C6B0006 for ; Tue, 17 Sep 2019 03:16:45 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id B7E722C12 for ; Tue, 17 Sep 2019 07:16:44 +0000 (UTC) X-FDA: 75943555128.06.laugh15_57f32b134ad5f X-HE-Tag: laugh15_57f32b134ad5f X-Filterd-Recvd-Size: 2878 Received: from Galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Tue, 17 Sep 2019 07:16:44 +0000 (UTC) Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1iA7j1-0004ha-7O; Tue, 17 Sep 2019 09:16:35 +0200 Date: Tue, 17 Sep 2019 09:16:35 +0200 From: Sebastian Andrzej Siewior To: Qian Cai Cc: peterz@infradead.org, mingo@redhat.com, akpm@linux-foundation.org, tglx@linutronix.de, thgarnie@google.com, tytso@mit.edu, cl@linux.com, penberg@kernel.org, rientjes@google.com, will@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, keescook@chromium.org Subject: Re: [PATCH] mm/slub: fix a deadlock in shuffle_freelist() Message-ID: <20190917071634.c7i3i6jg676ejiw5@linutronix.de> References: <1568392064-3052-1-git-send-email-cai@lca.pw> <20190916090336.2mugbds4rrwxh6uz@linutronix.de> <1568642487.5576.152.camel@lca.pw> <20190916195115.g4hj3j3wstofpsdr@linutronix.de> <1568669494.5576.157.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <1568669494.5576.157.camel@lca.pw> User-Agent: NeoMutt/20180716 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000664, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2019-09-16 17:31:34 [-0400], Qian Cai wrote: =E2=80=A6 > get_random_u64() is also busted. =E2=80=A6 > [=C2=A0=C2=A0753.486588]=C2=A0=C2=A0Possible unsafe locking scenario: >=20 > [=C2=A0=C2=A0753.493890]=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0C= PU0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0CPU1 > [=C2=A0=C2=A0753.499108]=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0-= ---=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0---- > [=C2=A0=C2=A0753.504324]=C2=A0=C2=A0=C2=A0lock(batched_entropy_u64.lock); > [=C2=A0=C2=A0753.509372]=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0lock(&= (&zone->lock)->rlock); > [=C2=A0=C2=A0753.516675]=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0lock(b= atched_entropy_u64.lock); > [=C2=A0=C2=A0753.524238]=C2=A0=C2=A0=C2=A0lock(random_write_wait.lock); > [=C2=A0=C2=A0753.529113]=C2=A0 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0*** DEADLOCK *** This is the same scenario as the previous one in regard to the batched_entropy_=E2=80=A6.lock. Sebastian