From owner-freebsd-hackers@freebsd.org Sat Jan 16 22:09:00 2016 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 518C1A859A8 for ; Sat, 16 Jan 2016 22:09:00 +0000 (UTC) (envelope-from vijju.singh@gmail.com) Received: from mail-vk0-x22c.google.com (mail-vk0-x22c.google.com [IPv6:2607:f8b0:400c:c05::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 12DEE138D; Sat, 16 Jan 2016 22:09:00 +0000 (UTC) (envelope-from vijju.singh@gmail.com) Received: by mail-vk0-x22c.google.com with SMTP id k1so315364292vkb.2; Sat, 16 Jan 2016 14:09:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=wfkq8mxjqUHoB+o6frkw+sVxAd4WtsJgeO5Ky/VKURg=; b=Ho9haDj0qFFz+wJNXkEZSFL4awuMT/NXWpSkB1ZcALVEAwi6V8nIuOTXLsNmIIEmJw Un0bPccoRO5S3UWHXYMyeZXe2x9Nd0AmECz/YQAGyv+c99cR491RZzZFOOjFL8ti3+ic YCE7UtL/AoKFQWCwJwOsVJnNsfV6RR2DYc4Cnsb1xK22aleoGZ9JQfr1FF8MHMJ8q86v xpBOvR796HJ+x4CgazCuSPuJgqjAFUrtxfYVg06nUJsDzBuyXS+Jgx3SnmY9673S01k3 8gs+ovw9Fch1517OUqEEAlkGZPApJBEe26YHK4NAxyb52hjDdgkjJ1bVmaBleM1YC2I+ hmAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=wfkq8mxjqUHoB+o6frkw+sVxAd4WtsJgeO5Ky/VKURg=; b=dHNermYV8FjdwP4B45v9Tjy5ktd0q41LxEGS/DKyWFpmCAPFRofgpPJrRTRFcnNUJW p8tHXw90HPiIFr9HVPVSpJf/w8mO7/+f91jNfSY4YU2K/MiTgR/geCZnq3Ia8dGRG3pm eAW3G3ubUf28lj8OPk+jg0A+KFbWBms/psPEB5gdnlNFEkUtbpUgVg/u8FNT1UvCMhkh 1XV7FNeblC/doav12HeRSYlCOLTdU1flqPRwEbpV54qgjrCbsrb3MX85YJZZgQNd174X PZcntgvmpTQD9xrUaTK0kV98oFSc+M7tpLfFJb7hcvoH1+btvPUbSp8GRfZU1EqbW9u3 oxKQ== X-Gm-Message-State: ALoCoQlCiS0NDj0JUbWwU/44wftVaF1F0fVRebyukWxshTKVl3j4I7InAf8kUCxoLi534jgdfO8VV5tNFWaZ/Yb/847mX6tnaA== MIME-Version: 1.0 X-Received: by 10.31.131.203 with SMTP id f194mr12837889vkd.90.1452982138735; Sat, 16 Jan 2016 14:08:58 -0800 (PST) Received: by 10.31.66.136 with HTTP; Sat, 16 Jan 2016 14:08:58 -0800 (PST) Received: by 10.31.66.136 with HTTP; Sat, 16 Jan 2016 14:08:58 -0800 (PST) In-Reply-To: <20160116202643.GL3942@kib.kiev.ua> References: <20160116195819.GA41610@chd.heemeyer.club> <20160116202643.GL3942@kib.kiev.ua> Date: Sat, 16 Jan 2016 14:08:58 -0800 Message-ID: Subject: Re: irrelevant locking From: Vijay Singh To: Konstantin Belousov Cc: Chagin Dmitry , freebsd-hackers@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 16 Jan 2016 22:09:00 -0000 Couldn't the get & set race otherwise? On Jan 16, 2016 12:27 PM, "Konstantin Belousov" wrote: > On Sat, Jan 16, 2016 at 10:58:19PM +0300, Chagin Dmitry wrote: > > hi, please, can someone explain the reason to take the process lock here: > There is no reason, I think that the PROC_LOCK() can be removed. > > > > > int > > sys_issetugid(register struct thread *td, struct issetugid_args *uap) > > { > > struct proc *p = td->td_proc; > > > > /* > > * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, > > * we use P_SUGID because we consider changing the owners as > > * "tainting" as well. > > * This is significant for procs that start as root and "become" > > * a user without an exec - programs cannot know *everything* > > * that libc *might* have put in their data segment. > > */ > > PROC_LOCK(p); > > td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0; > > PROC_UNLOCK(p); > > return (0); > > } > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >