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=-10.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 12805C43441 for ; Sun, 18 Nov 2018 16:03:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD3C62086B for ; Sun, 18 Nov 2018 16:03:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bvQj4EyP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD3C62086B Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727574AbeKSCX4 (ORCPT ); Sun, 18 Nov 2018 21:23:56 -0500 Received: from mail-ua1-f65.google.com ([209.85.222.65]:39295 "EHLO mail-ua1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726804AbeKSCX4 (ORCPT ); Sun, 18 Nov 2018 21:23:56 -0500 Received: by mail-ua1-f65.google.com with SMTP id k10so9887079ual.6 for ; Sun, 18 Nov 2018 08:03:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=gRfyDfiiU8nLoSYxo7HvgBdNLY/gqZEp2pdSSXhnYbg=; b=bvQj4EyP2MeBuJTOYfXrOGP2M4G0MoXjLadOTCYVzVUds02wtiEm74DGc94bq+zyj+ DzSRwaREiDGvGWs7RpavnORb5sDSvOZLzXvAD6vY2oWGfiM5gjrpnShfWY5TMXDkp6dg Hv1lbPrioAnOgQPZG+z2gwwcbISipsGU7K0QoKJl8Q2I18orU0iANBEI9aShx2VLuHqj J9i2Z1jdJd4Ng5L/Jfvxx3KWQwEZdKf8hzYAxvVMFbjDfyQXA1/Mwci5e6ztZorKm7fr 6G5q4fnzzYfCzbwgtIzl5olUC+X9IRsNXXeTYxpIQM1F+a3wIK0wjrlQcAmzeVDL+y53 XJvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=gRfyDfiiU8nLoSYxo7HvgBdNLY/gqZEp2pdSSXhnYbg=; b=WHKLGBnnnkjucY3f9TNebBXrtuZMUBeqr1NUuMRJdFGdUB88AhWy75WJBhr6lGTuF7 8QjY/Ab6DZJ32GKrUAZRjelKdNTnbCV6PFlupO/W51yvf1IXSv3PRvjCowY0+VQOei84 2g8UoKO6OI7GaLr9x8L+4pRTufQ2cGBmtx1xtmnAuwDLSCn6PspU+DIqzCNhHXGPqoHB 567sAadC60tXEC2ObYFHbP8a1QvWJVfj0CaOfA2qDiXCq3Q15wgwyI/oGezFzj759BjD W69RSQmK2xTTnMMkM5jA7uV4Hx04pYITpA3h94sj/zM1Hplpr4w/jsikZmFp37Bl5eti k0ew== X-Gm-Message-State: AGRZ1gLeVG4n17BqpI+jpmLdHqZv4SgtTdg87I+4aXOr16ihOjZ96mIN jdJnHG6q3rC4VJ5plAVZwMWVGchLpP4r8WF0xXKlEQ== X-Google-Smtp-Source: AJdET5cgpDxk+GREMOwggztRRwS7d7lH143iwJnq3FBVpvtMtmsSFZuOQ+XXJ6sOsstqoTD8GPrng276Joq00nOHyyE= X-Received: by 2002:a9f:2b44:: with SMTP id q4mr5431609uaj.126.1542556996603; Sun, 18 Nov 2018 08:03:16 -0800 (PST) MIME-Version: 1.0 Received: by 2002:a67:f48d:0:0:0:0:0 with HTTP; Sun, 18 Nov 2018 08:03:15 -0800 (PST) In-Reply-To: <20181118111751.6142-1-christian@brauner.io> References: <20181118111751.6142-1-christian@brauner.io> From: Daniel Colascione Date: Sun, 18 Nov 2018 08:03:15 -0800 Message-ID: Subject: Re: [PATCH] proc: allow killing processes via file descriptors To: Christian Brauner Cc: "Eric W. Biederman" , linux-kernel , "Serge E. Hallyn" , Jann Horn , Andy Lutomirski , Andrew Morton , Oleg Nesterov , Aleksa Sarai , Al Viro , Linux FS Devel , Linux API , Tim Murray , Kees Cook Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 18, 2018 at 3:17 AM, Christian Brauner wrote: > +static int proc_tgid_open(struct inode *inode, struct file *file) > +{ > + /* grab reference to struct pid */ > + file->private_data = get_pid(proc_pid(inode)); Why grab another reference to the struct pid when the inode already has one?