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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 50D5CC0044C for ; Thu, 1 Nov 2018 10:50:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 13798205F4 for ; Thu, 1 Nov 2018 10:50:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13798205F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cyphar.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 S1728111AbeKATwi (ORCPT ); Thu, 1 Nov 2018 15:52:38 -0400 Received: from mx1.mailbox.org ([80.241.60.212]:55278 "EHLO mx1.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726712AbeKATwi (ORCPT ); Thu, 1 Nov 2018 15:52:38 -0400 Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mx1.mailbox.org (Postfix) with ESMTPS id 9F63D4B6C5; Thu, 1 Nov 2018 11:50:10 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter02.heinlein-hosting.de (spamfilter02.heinlein-hosting.de [80.241.56.116]) (amavisd-new, port 10030) with ESMTP id vwuC7OzXJZOW; Thu, 1 Nov 2018 11:49:59 +0100 (CET) Date: Thu, 1 Nov 2018 21:49:48 +1100 From: Aleksa Sarai To: Masami Hiramatsu Cc: Steven Rostedt , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Brendan Gregg , Christian Brauner , Aleksa Sarai , linux-kernel@vger.kernel.org Subject: Re: [PATCH] kretprobe: produce sane stack traces Message-ID: <20181101104948.bc7wk453bfryhhk7@yavin> References: <20181026132210.12569-1-cyphar@cyphar.com> <20181030101206.2e5998ca3c75496c91ba5b09@kernel.org> <20181031090317.4e211fdd@vmware.local.home> <20181031133912.3j5tryq2vyhkdn4d@yavin> <20181101191347.74eadff4a5d1fab2d79d7efe@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="mfvf6vzxsoivpjki" Content-Disposition: inline In-Reply-To: <20181101191347.74eadff4a5d1fab2d79d7efe@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --mfvf6vzxsoivpjki Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-11-01, Masami Hiramatsu wrote: > > > > Anyway, until that merge happens, this patch looks good to avoid > > > > this issue for generic solution (e.g. for the arch which doesn't > > > > supports retstack). > > >=20 > > > I think its time to come up with an algorithm that makes function gra= ph > > > work with multiple users, and have kretprobes be able to hook into it > > > just like kprobes hooks into function tracer. > > >=20 > > > I have some ideas on how to get this done, and will try to have an RFC > > > patch set ready by plumbers. > >=20 > > Should I continue working on this patchset? >=20 > Yes, until we finally introduce Steven's algorithm on all arch (yeah, we = still > have some archs which don't support graph-tracer but supports kprobes), > I think your patch is the best fix for this issue. Thanks, I just sent a v3. Though, even with Steven's hooking of kprobes I think you'd still need to stash away the stack trace somewhere (or am I misunderstanding the proposal?). --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --mfvf6vzxsoivpjki Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEb6Gz4/mhjNy+aiz1Snvnv3Dem58FAlva2ksACgkQSnvnv3De m5+IKA//fWlK5aWXmaK9C+YmWL1Q3IG+m4i6rzoV42tQO3bZkFWwomExK/zvk6p0 ojzzXTffRBApcmUGqGEZPVHI1evGwHx5Xb60yFSFYXeIJmp5soeZuQEjK+NVpMo+ onnd+yNNevsBgRd6wEM+RM19mu8RaoakdYKB3D9m020p7VSkpXY1nHHznKdxzm+O xhD3ePM6ObgTPRVxy30FvtjNtf4RNaLKBBJfoflAnRsKsLaHCUt+yXISHaL0TpbR FDpZ+p01AE5nOA6hjM33ekYM4/p0TQ4YRNtCQz5lxUALcdyngkzD14f3DvUyuKQl wQRxe8S5LU3ePHeocLCvcVVZ3jgz9bxooeyRVTd4pjlSxrPn26lWMYBxN+U4LRoA qhwkccS9vgqJwMfhPdvmI97iiMm2Y9bD5htZK80Tmb6bLNnnJR4kFiKYcIcpPcG2 Ml/qoYLdn0MXE+SEQ25Rao0ql8YZsiWXqyNMBWcJCWwIg2dJ1oldZGnajjGRL9wy lly6v8RpS5tPBOnDvP4glazDj8mIXCCXbOj/3RnAvR6ci3PneWCKm2fA1kM1T5YK HTnCSpkKkPySYhafQUF+CP/hiUuFQg4mo3opjbug8i9jhjNrj8ffUlzMFF2z1VDZ SQMRu9KUCX+mC34h2yYuq8H/tVZ+exv4Xxm6m5UUR00Z9H3S6Y4= =bD1t -----END PGP SIGNATURE----- --mfvf6vzxsoivpjki--