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 ADA23413D63 for ; Fri, 15 May 2026 20:16:08 +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=1778876169; cv=none; b=HbyhO/w2xxkAlCK4wqa+m//b1MdeP3x9vyNAvDdeyrRy/ceOTSjmiqQHX7cWtiRz7aa/ZT9OW1Ni7HCppb0QHWFmluZCddx6aTeJGLVanvpJJVkvbKCmOgMS+hcDs39gBbRXaQaHrCfgW4lA1f5JU9J3eBtlLasAVLiPtyU3Ey8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778876169; c=relaxed/simple; bh=VvDbho/ycMJrj4/etDVpBHhuznbtd+KBBl2aXO2hAg8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XpIx8yLtD8agsw/c7i3vX/oJqYOvLrjFJxG3snXqyZdc+Mw2Vc3ZwsyEiPiD88AmDRwu6/nt8DbS8MG4pUCRZYNHCjo90aofxURMN7KKGWUWC1HWK1nCRq7YauOQ3sJFZOhqIdIZVaN1uDE1bOUREV1cZjednjVIiahOzB0nVyI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=K04+VwbP; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="K04+VwbP" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1778876167; 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=VvDbho/ycMJrj4/etDVpBHhuznbtd+KBBl2aXO2hAg8=; b=K04+VwbPUAHc6RTr6nEaAassI7+7h2Sx0TifmC+1/JvABi95yfnq2nqxo+HcZDa3aEF3D0 ltg5PY+tjetm7XDa4A6J1G79X0OosPOy0Hac/2vJcINXkJxgcTs3sWNi2zZGt9u8hFtbvU qw3icI7Ihu+9E9NjyxRWayhNEvSSPLY= 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-342-3gJze-F2PlKucRHeD5WMxQ-1; Fri, 15 May 2026 16:16:02 -0400 X-MC-Unique: 3gJze-F2PlKucRHeD5WMxQ-1 X-Mimecast-MFC-AGG-ID: 3gJze-F2PlKucRHeD5WMxQ_1778876160 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 D6E9E19560B4; Fri, 15 May 2026 20:15:59 +0000 (UTC) Received: from fedora (unknown [10.44.32.66]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 3D3C930001A2; Fri, 15 May 2026 20:15:54 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 15 May 2026 22:15:59 +0200 (CEST) Date: Fri, 15 May 2026 22:15:53 +0200 From: Oleg Nesterov To: Christian Brauner Cc: Minchan Kim , Jann Horn , Linus Torvalds , akpm@linux-foundation.org, hca@linux.ibm.com, linux-s390@vger.kernel.org, david@kernel.org, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, surenb@google.com, timmurray@google.com Subject: Re: [PATCH v3] mm: process_mrelease: introduce PROCESS_MRELEASE_REAP_KILL flag Message-ID: References: <20260511214226.937793-1-minchan@kernel.org> <20260515-nachdenken-umbenannt-a90006a46e14@brauner> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260515-nachdenken-umbenannt-a90006a46e14@brauner> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 In fact I don't even understand the motivation... On 05/15, Christian Brauner wrote: > > On Mon, May 11, 2026 at 02:42:26PM -0700, Minchan Kim wrote: > > leaving the actual address space teardown (exit_mmap) to be deferred until > > the mm's reference count drops to zero. In the field (e.g., Android), > > arbitrary reference counts (reading /proc//cmdline, or various other > > remote VM accesses) frequently delay this teardown indefinitely, Sure, get_task_cmdline() can delay mmput(). But indefinitely ? Perhaps the changelog could be more clear? I don't see how any remote VM access can pin mm->mm_users "indefinitely". Even if, say, a lot of threads read /proc//cmdline in an endless loop in parallel... I must have missed something. Oleg.