From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C570A1A38E7 for ; Thu, 1 Aug 2024 13:59:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722520753; cv=none; b=KOzxuHtwEakzVtJvJrp1ITM6UhtBFnYroB75l7lPkc7ApeeVhLdZl4zEx/dudhkatUajg00AFEud0KDdfi/tT3B0+YxG/1yxHzr/LpEJZeTYV5kuoVU1xvRnt+fZ1WEbyswx6YdagIttleJ6KLAj+MW72EMx67c+cId4TA0LxG8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722520753; c=relaxed/simple; bh=MpNMcGFJ5X/GwjRYuU61MJgNlI8OH/7MgAUOA9PeOLc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ioImZmlnN86xOzNc19iz1Bi9ZsfEsVAT1WxsH35i/9J0bV6xvh40mwzb7eE+SFeWKpp8T4zujg64b+JuNPs+UGBUnQG1Dsk3HUpdunAbhu9Bt4GSKack14Z2LTywHLku/nDAVIG/1HVKDyQum8fNLR7uNYrH8+R0jAvDHWKEJeA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=K0mcy206; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="K0mcy206" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722520750; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MpNMcGFJ5X/GwjRYuU61MJgNlI8OH/7MgAUOA9PeOLc=; b=K0mcy206WoOXvEqEOMdMds1ziG8Om3kNHyChAkXpl8PQnWX7ntrA7XDIx22pL7StZpcGS8 9QFP7Cv0yDOnxL1NS0jqPHrAilyIEoxjuz9Smm4wdgzlBN7i5+9jLWm0q7o67++s+kdnwH hV+eCuCjUWateZUKgg42R7XJbfmSg60= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-674-JMTiKpvCMY2YDExVGLVEwQ-1; Thu, 01 Aug 2024 09:59:07 -0400 X-MC-Unique: JMTiKpvCMY2YDExVGLVEwQ-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B20571955D52; Thu, 1 Aug 2024 13:59:05 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.183]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 7B53B1955D42; Thu, 1 Aug 2024 13:59:02 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 1 Aug 2024 15:59:05 +0200 (CEST) Date: Thu, 1 Aug 2024 15:59:01 +0200 From: Oleg Nesterov To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Aleksa Sarai , Tycho Andersen , Daan De Meyer , Tejun Heo , stable@vger.kernel.org Subject: Re: [PATCH] pidfd: prevent creation of pidfds for kthreads Message-ID: <20240801135900.GD4038@redhat.com> References: <20240731-gleis-mehreinnahmen-6bbadd128383@brauner> <20240731145132.GC16718@redhat.com> <20240801-report-strukturiert-48470c1ac4e8@brauner> <20240801080120.GA4038@redhat.com> <20240801-clever-mitleid-da9b4142edde@brauner> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240801-clever-mitleid-da9b4142edde@brauner> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On 08/01, Christian Brauner wrote: > > On Thu, Aug 01, 2024 at 10:01:20AM GMT, Oleg Nesterov wrote: > > OK, I won't argue, but .... > > > > > you may or may not get notified > > > via poll when a kthread exits. > > > > Why? the exiting kthread should not differ in this respect? > > Why do you want to allow it? Again, I didn't try to "nack" your patch. Just tried to understand your motivation. And "may not get notified" above doesn't look right to me... > > /proc/$pid/status has a "Kthread" field... > > Going forward, I don't want to force people to parse basic stuff out of > procfs. Ideally, they'll be able to mostly rely on pidfd operations > only. Agreed. Oleg.