From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30896 invoked by alias); 7 Jan 2015 12:07:50 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 30884 invoked by uid 89); 7 Jan 2015 12:07:47 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 07 Jan 2015 12:07:45 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t07C7hCg024300 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 7 Jan 2015 07:07:43 -0500 Received: from localhost.localdomain (vpn-52-228.rdu2.redhat.com [10.10.52.228]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t07C7emM005795; Wed, 7 Jan 2015 07:07:41 -0500 Message-ID: <54AD218B.6020002@redhat.com> Date: Wed, 07 Jan 2015 12:07:00 -0000 From: Pratyush Anand User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: William Cohen , systemtap@sourceware.org, "arm@lists.fedoraproject.org" Subject: Re: arm64 uprobes support showing signs of life References: <54AAB673.6040200@redhat.com> In-Reply-To: <54AAB673.6040200@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2015-q1/txt/msg00007.txt.bz2 Hi Will, On Monday 05 January 2015 09:36 PM, William Cohen wrote: > Hi All, > > Pratyush has been implementing uprobes support for aarch64 and has > posted a set of patches > (http://comments.gmane.org/gmane.linux.ports.arm.kernel/382237) for > review. The really new Linux kernels requires a patch to the > systemtap runtime because the f_dentry macro has been removed. With > the patched systemtap I was able to run the systemtap testsuite and > get some test results exercising the uprobes support: > > https://web.elastic.org/~dejazilla/viewsummary.php?summary=%3D%27%3C54A9E21C.2080504%40redhat.com%3E%27 > > There looked to be a localized fixes for plt support to eliminate the > unsupported systemtap.base/list.exp plt-* tests. > > A number of the tests appear to fail because of userspace arguments > cannot be found for sdt probes. > > The uprobe patches still need some refinement. On a number of > systemtap "make installcheck" runs the kernel would get stuck spewing > out: > > Unexpected kernel single-step exception at EL1 There are at least two functions of arm64/uprobe implementation uprobe_breakpoint_handler and uprobe_single_step_handler, where a kprobe insertion might be causing above issue. Currently I have qualified these functions with __kprobe, so that one can not insert a kprobe there. With this you should not be able to see the above message. However, I am still investigating if a kprobe insertion be allowed to these functions or any other function which is called directly from debug exception handler (do_debug_exception) Update code is here: https://github.com/pratyushanand/linux.git : ml_arm64_uprobe_devel_v2 ~Pratyush > > However, things are looking better for user-space probing on arm64. > > -Will >