From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760745AbdEOJ1w (ORCPT ); Mon, 15 May 2017 05:27:52 -0400 Received: from ozlabs.org ([103.22.144.67]:47609 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760513AbdEOJZG (ORCPT ); Mon, 15 May 2017 05:25:06 -0400 From: Michael Ellerman To: Jessica Yu Cc: linuxppc-dev@ozlabs.org, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/modules: If mprofile-kernel is enabled add it to vermagic In-Reply-To: <20170512072012.lbiuoqexbai75ypy@jeyu> References: <1494399469-17833-1-git-send-email-mpe@ellerman.id.au> <20170512072012.lbiuoqexbai75ypy@jeyu> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Mon, 15 May 2017 19:24:58 +1000 Message-ID: <871srqbhg5.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jessica Yu writes: > +++ Michael Ellerman [10/05/17 16:57 +1000]: >>On powerpc we can build the kernel with two different ABIs for mcount(), which >>is used by ftrace. Kernels built with one ABI do not know how to load modules >>built with the other ABI. The new style ABI is called "mprofile-kernel", for >>want of a better name. >> >>Currently if we build a module using the old style ABI, and the kernel with >>mprofile-kernel, when we load the module we'll oops something like: >> >> # insmod autofs4-no-mprofile-kernel.ko >> ftrace-powerpc: Unexpected instruction f8810028 around bl _mcount >> ------------[ cut here ]------------ >> WARNING: CPU: 6 PID: 3759 at ../kernel/trace/ftrace.c:2024 ftrace_bug+0x2b8/0x3c0 >> CPU: 6 PID: 3759 Comm: insmod Not tainted 4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 #11 >> ... >> NIP [c0000000001eaa48] ftrace_bug+0x2b8/0x3c0 >> LR [c0000000001eaff8] ftrace_process_locs+0x4a8/0x590 >> Call Trace: >> alloc_pages_current+0xc4/0x1d0 (unreliable) >> ftrace_process_locs+0x4a8/0x590 >> load_module+0x1c8c/0x28f0 >> SyS_finit_module+0x110/0x140 >> system_call+0x38/0xfc >> ... >> ftrace failed to modify >> [] 0xd000000002a31024 >> actual: 35:65:00:48 >> >>We can avoid this by including in the vermagic whether the kernel/module was >>built with mprofile-kernel. Which results in: >> >> # insmod autofs4-pg.ko >> autofs4: version magic >> '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 SMP mod_unload modversions ' >> should be >> '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269-dirty SMP mod_unload modversions mprofile-kernel' >> insmod: ERROR: could not insert module autofs4-pg.ko: Invalid module format >> >>Signed-off-by: Michael Ellerman > > Looks good to me: > > Acked-by: Jessica Yu Thanks. cheers