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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 369FEC433E0 for ; Wed, 3 Feb 2021 22:18:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9B5664DF0 for ; Wed, 3 Feb 2021 22:18:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232184AbhBCWSL (ORCPT ); Wed, 3 Feb 2021 17:18:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229897AbhBCWSK (ORCPT ); Wed, 3 Feb 2021 17:18:10 -0500 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09C5AC061573; Wed, 3 Feb 2021 14:17:30 -0800 (PST) Received: by mail-lj1-x236.google.com with SMTP id m22so961945ljj.4; Wed, 03 Feb 2021 14:17:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=fwKwcjkOakabuMC8IDDuvslB5j91FzNr2ME4Ak/U/ps=; b=V5L8auhbCPrs/G84QeTojaX6uGf030RjbQ/EHQpDA9BBU7ay28h+u1Yt0AjcJEsPJd /YO0xAMPgKvxqnqYh67F5qEX9gwUrYgsEDvxg2AkPheyc/em2Gz+bKtJem0VcUAhFO8x Rr5jnVRW7+e4QfMjp4dGYgCedjvP2MFLa9UDcRcNblPfW0wtYT6aEE5bajWeIbWMIyRu qr+vBSAR21aCXAti7QHDpnoa3Q0en3k3ictIAF/sk/T4dtxtshxdx4zIys9zxuIoR3oM dC6VJfjJoRDI+mNzvnfuW0BWHER+9vA5yb9UhLygriS3GScTyjm4WZixMKJ9IFJAIW95 FLcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=fwKwcjkOakabuMC8IDDuvslB5j91FzNr2ME4Ak/U/ps=; b=EOumvuG/iEzmihnI+kUPfEqIepqWNkBPFUSQ1yeJO/cHuaVL2x+oFHP2RvCZdRurDQ LvkQ9iQ5Dp+SD7zsB5lRomN6jCnAVGRJCmakKdrlw67QEjQoPAd1etaGQNPlgEOf0KO/ tppAqek8+UfVj6omHZi+Ne+e30i/fL/X6tO3KTLyyj7ImIYxr5G/7VPmU5jKCBOfAVY7 ogPKPGVo1v6pqeAgbf/2Px6Z2cpmrkkh1HtNNREHNqKY9+CzLn2fIfue8NlB7spea2Tz cx4t+JaOf5WnCt2YM2IcnpAtyQ88vhBCrqoA5+fLLS+MMjMBareHy1VwdVu2WFcR08nA nNmQ== X-Gm-Message-State: AOAM533VVKEsgspawJkCd1DAuzAZUiEmBEUEDKM9NXkE8xQsg6NZiQao kEdH+OlC5mbMh5dABmMHKHE= X-Google-Smtp-Source: ABdhPJyr7sA80ksw4CHNkRXkXYkTRduS44pOEpiEJNOCT54lrNGXz9TRkEjoSHNY6oPMDSOnvq4NHQ== X-Received: by 2002:a2e:b543:: with SMTP id a3mr2968626ljn.336.1612390648430; Wed, 03 Feb 2021 14:17:28 -0800 (PST) Received: from grain.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id g27sm362995lfh.291.2021.02.03.14.17.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Feb 2021 14:17:27 -0800 (PST) Received: by grain.localdomain (Postfix, from userid 1000) id 64ABA560097; Thu, 4 Feb 2021 01:17:26 +0300 (MSK) Date: Thu, 4 Feb 2021 01:17:26 +0300 From: Cyrill Gorcunov To: Pavel Tikhomirov Cc: Jeff Layton , Jeff Layton , "J. Bruce Fields" , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andrei Vagin Subject: Re: [PATCH] fcntl: make F_GETOWN(EX) return 0 on dead owner task Message-ID: <20210203221726.GF2172@grain> References: <20210203124156.425775-1-ptikhomirov@virtuozzo.com> <20210203193201.GD2172@grain> <88739f26-63b0-be1d-4e6d-def01633323e@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <88739f26-63b0-be1d-4e6d-def01633323e@virtuozzo.com> User-Agent: Mutt/1.14.6 (2020-07-11) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Feb 04, 2021 at 12:35:42AM +0300, Pavel Tikhomirov wrote: > > AFAICS if pid is held only by 1) fowner refcount and by 2) single process > (without threads, group and session for simplicity), on process exit we go > through: > > do_exit > exit_notify > release_task > __exit_signal > __unhash_process > detach_pid > __change_pid > free_pid > idr_remove > > So pid is removed from idr, and after that alloc_pid can reuse pid numbers > even if old pid structure is still alive and is still held by fowner. ... > Hope this answers your question, Thanks! Yeah, indeed, thanks! So the change is sane still I'm a bit worried about backward compatibility, gimme some time I'll try to refresh my memory first, in a couple of days or weekend (though here are a number of experienced developers CC'ed maybe they reply even faster).