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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT 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 B4E83C43381 for ; Tue, 19 Mar 2019 17:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8767020863 for ; Tue, 19 Mar 2019 17:47:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553017656; bh=glXpESmb8KvD8pi524J9aPEOAw15KniUMe1SWTzOc08=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=c3yKrGGor7KOMFwEfWBM/ZXEOeLX8zXbk8UKzKv4ZTNlhEj7enIftx2S6STMXJG0q UdRHe7rlQtiYKUT5k9X9dU5hN1eZTwVXZdlKrMdlZvsoq1hp6DVkn7S3EYqImmNKnF yuyh+6SJv3IjfTei4UZlcf1NYFLqZRw3A7/jrIPw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727087AbfCSRrb (ORCPT ); Tue, 19 Mar 2019 13:47:31 -0400 Received: from mail-yw1-f67.google.com ([209.85.161.67]:46726 "EHLO mail-yw1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726944AbfCSRrb (ORCPT ); Tue, 19 Mar 2019 13:47:31 -0400 Received: by mail-yw1-f67.google.com with SMTP id v127so16309711ywe.13; Tue, 19 Mar 2019 10:47:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3TV5JSMWzDFmGtM2a9PqyZpbM8Cae0apS79wiWWNBuA=; b=Of9nZV6g8OozSHtv9gaoyJHGTNVH7aXpFqRf7RG2ulzzh7pwgQj53Ja9kX4SRoysBf WTKUwYdhh2cfDrebplPomarUMEhL9wABj/zt2or1kA+U9nPmOmvu8bTqYnxuZcgNZUmU tkP6/jg11wyPjsJxwqSNiWbSz57afpm12rthIEQM5jtGDCutSoQDnwIcSgNiW/mDuErG CublhaTz5si8j5tJnDxiB8H4gboyWwZw9o34/V5gWFi4+u58GPYemOmMoJ9Iekhxniya i5AQNeWP/Whmt+HztHFXJQdO2K12aJk/BkdI/7D0PdklhRP84DYlAqncJICe247p4L5Y yU4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=3TV5JSMWzDFmGtM2a9PqyZpbM8Cae0apS79wiWWNBuA=; b=LpzB2GYUUg4vvVjEqGZxVxdzny8+ixFOlg0pYC3O5tGlFMC41o+40V0P2MP0l7J9oI eSdNdgMi88W4VpmZCs1jIu4mIMoNQaveKSl+bUJ2efN2koS+hoCXdo/HxH6TQl3Ss5Px hNnYNeiYVnJ7pfe+CW3cXf6s6gxDALKPan7jfAhEOS+VKyimLpDverfBS2zcvpEvA68+ o5c6eWWkIjFiWEenLqE7UDWOLH03YDJyUSfSX+TBSBS3p/Hb392Gcewl6wPRLXJFuABA ZbiG+m0sALPRKgt0ydHukBXg4YNJx7FbooJ6thw87nCtWD5fnDYiAYlr6tORUfj2+8tL obvQ== X-Gm-Message-State: APjAAAVZ/58O6FftuZHbAwUU06RBGvDLTDhcSPMlOpK1JINGHf8ekaMZ nOVeXwnvr/WwB2mWsZfA46o= X-Google-Smtp-Source: APXvYqwHDJ7YG7jNKx+tHayfCaH93EKIvt1NPX/iUHmKCXdnAs6bD1EZDII0MdWTJsBN7A+pOzcaDQ== X-Received: by 2002:a25:c9c7:: with SMTP id z190mr2210886ybf.234.1553017649632; Tue, 19 Mar 2019 10:47:29 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::2:5a18]) by smtp.gmail.com with ESMTPSA id o64sm8805ywb.25.2019.03.19.10.47.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 Mar 2019 10:47:28 -0700 (PDT) Date: Tue, 19 Mar 2019 10:47:25 -0700 From: Tejun Heo To: Jann Horn Cc: James Morris , "Serge E. Hallyn" , Li Zefan , Johannes Weiner , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Aristeu Rozanski , "Serge E . Hallyn" , Michal Hocko , cgroups@vger.kernel.org Subject: Re: [PATCH] device_cgroup: fix RCU imbalance in error case Message-ID: <20190319174725.GA69236@devbig004.ftw2.facebook.com> References: <20190319013659.86199-1-jannh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190319013659.86199-1-jannh@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Tue, Mar 19, 2019 at 02:36:59AM +0100, Jann Horn wrote: > When dev_exception_add() returns an error (due to a failed memory > allocation), make sure that we move the RCU preemption count back to where > it was before we were called. We dropped the RCU read lock inside the loop > body, so we can't just "break". > > sparse complains about this, too: > > $ make -s C=2 security/device_cgroup.o > ./include/linux/rcupdate.h:647:9: warning: context imbalance in > 'propagate_exception' - unexpected unlock > > Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()") > Cc: stable@vger.kernel.org > Signed-off-by: Jann Horn Applied to cgroup/for-5.1-fixes. Thanks. -- tejun