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=-8.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1, USER_IN_DEF_DKIM_WL autolearn=no 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 227ABCA9EB6 for ; Wed, 23 Oct 2019 10:49:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DCDB8214B2 for ; Wed, 23 Oct 2019 10:49:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="U26NV0Rn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404524AbfJWKtp (ORCPT ); Wed, 23 Oct 2019 06:49:45 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:51846 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390513AbfJWKto (ORCPT ); Wed, 23 Oct 2019 06:49:44 -0400 Received: by mail-wm1-f66.google.com with SMTP id q70so13505291wme.1 for ; Wed, 23 Oct 2019 03:49:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=x9Us54scadrFU9TiJRijJVT2Q9RuXcN3VvdzhxCj4XY=; b=U26NV0Rn2z8GAYz7San694T0J7eRwl0thTNtkgIkNJbPPn3lCOykKiV+flHFRJpwC+ EL/N+kAKyd2IGN8eHHgGMBT06Zh2c9WBVfFzIdUDcC3SSQVULEqtMv+OzEpDSToN0OFD WEyTLxg8vnRRUxk1WnWTlJgjqlCJMDyjJ8PJKS3azVFAQD2Q1uuRG1jMq7oo05lcpyzq E7cy1R7pTtSxN0OH34YhoAu4Ox6cAcp+CpwdU5fwa/V8T2vTJ8Xr1VNORzokC77qk98Q zjIPIb0BLVk0cJT1BT7EbBtrSsNOznmZRlGdVN+x5r959X4DWLWDfcIerfX6StGUQ+RW zy6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=x9Us54scadrFU9TiJRijJVT2Q9RuXcN3VvdzhxCj4XY=; b=aANCoVDlj0ZYCsWduNmLPdK9DqkFsIjmwsrtJlXckgavLDLwh4FtJenQWP6kdIy+C6 oX3T/UWVFVuHlSPBi1/UJVEmemQhBKXNxORk/KyAJWh47Q0gji+0CN3xqW2951d/pHRq 82nBwSMu5vbCjiu02IsWCgdnLMh8JMOJK5PiPi469yHFwBxbO0fIvZdv3jSvP/qYvxkd OO9We5UO0w7WIpPI/UgLR3tRRplR6tPxN+OXA8RF7xE6jBAPSlcspY+hw71dk/RWWvd0 w2rdRrus7auf9BUiBVqIHPXT1Py+F8k66Oc4rUy3BmBxgRSNDwICgCByL2tcBtQsPsKw lDkw== X-Gm-Message-State: APjAAAUS9gbER89mpDK8ALo33UyxyAZJxGV5laNhA4NB0pO7N4FQwPQg 7T8Fj5nsaMpgX5RP4D6kezLEtg== X-Google-Smtp-Source: APXvYqygvI1eXHgm4oUC8Ldg/5UwX2sIRJ8S+0hGdEWx4GhRDVei8QAywYaoDflMC0ZQnEAqV+p+1g== X-Received: by 2002:a1c:f011:: with SMTP id a17mr15921wmb.18.1571827781378; Wed, 23 Oct 2019 03:49:41 -0700 (PDT) Received: from google.com ([2a00:79e0:d:210:e8f7:125b:61e9:733d]) by smtp.gmail.com with ESMTPSA id w18sm3945309wrl.75.2019.10.23.03.49.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Oct 2019 03:49:40 -0700 (PDT) Date: Wed, 23 Oct 2019 11:49:40 +0100 From: Matthias Maennich To: Luis Chamberlain Cc: Heiner Kallweit , Jessica Yu , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli Subject: Re: Module loading problem since 5.3 Message-ID: <20191023104940.GD27616@google.com> References: <20191014085235.GW16384@42.do-not-panic.com> <20191014144440.GG35313@google.com> <20191016125030.GH16384@42.do-not-panic.com> <20191016133710.GB35139@google.com> <20191018121848.GB11244@42.do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191018121848.GB11244@42.do-not-panic.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Oct 18, 2019 at 12:18:48PM +0000, Luis Chamberlain wrote: >On Wed, Oct 16, 2019 at 02:37:10PM +0100, Matthias Maennich wrote: >> On Wed, Oct 16, 2019 at 12:50:30PM +0000, Luis Chamberlain wrote: >> > On Mon, Oct 14, 2019 at 03:44:40PM +0100, Matthias Maennich wrote: >> > > Hi Luis! >> > > >> > > On Mon, Oct 14, 2019 at 08:52:35AM +0000, Luis Chamberlain wrote: >> > > > On Fri, Oct 11, 2019 at 09:26:05PM +0200, Heiner Kallweit wrote: >> > > > > On 10.10.2019 19:15, Luis Chamberlain wrote: >> > > > > > >> > > > > > >> > > > > > On Thu, Oct 10, 2019, 6:50 PM Heiner Kallweit > wrote: >> > > > > > >> > > > > >    MODULE_SOFTDEP("pre: realtek") >> > > > > > >> > > > > > Are you aware of any current issues with module loading >> > > > > > that could cause this problem? >> > > > > > >> > > > > > >> > > > > > Nope. But then again I was not aware of MODULE_SOFTDEP(). I'd encourage an extension to lib/kmod.c or something similar which stress tests this. One way that comes to mind to test this is to allow a new tests case which loads two drives which co depend on each other using this macro. That'll surely blow things up fast. That is, the current kmod tests uses request_module() or get_fs_type(), you'd want a new test case with this added using then two new dummy test drivers with the macro dependency. >> > > > > > >> > > > > > If you want to resolve this using a more tested path, you could have request_module() be used as that is currently tested. Perhaps a test patch for that can rule out if it's the macro magic which is the issue. >> > > > > > >> > > > > >   Luis >> > > > > >> > > > > Maybe issue is related to a bug in introduction of symbol namespaces, see here: >> > > > > https://lkml.org/lkml/2019/10/11/659 >> > > > >> > > > Can you have your user with issues either revert 8651ec01daed or apply the fixes >> > > > mentioned by Matthias to see if that was the issue? >> > > > >> > > > Matthias what module did you run into which let you run into the issue >> > > > with depmod? I ask as I think it would be wise for us to add a test case >> > > > using lib/test_kmod.c and tools/testing/selftests/kmod/kmod.sh for the >> > > > regression you detected. >> > > >> > > The depmod warning can be reproduced when using a symbol that is built >> > > into vmlinux and used from a module. E.g. with CONFIG_USB_STORAGE=y and >> > > CONFIG_USB_UAS=m, the symbol `usb_stor_adjust_quirks` is built in with >> > > namespace USB_STORAGE and depmod stumbles upon this emitting the >> > > following warning (e.g. during make modules_install). >> > > >> > > depmod: WARNING: [...]/uas.ko needs unknown symbol usb_stor_adjust_quirks >> > > >> > > As there is another (less intrusive) way of implementing the namespace >> > > feature, I posted a patch series [1] on last Thursday that should >> > > mitigate the issue as the ksymtab entries depmod eventually relies on >> > > are no longer carrying the namespace in their names. >> > > >> > > Cheers, >> > > Matthias >> > > >> > > [1] https://lore.kernel.org/lkml/20191010151443.7399-1-maennich@google.com/ >> > >> > Yes but kmalloc() is built-in, and used by *all* drivers compiled as >> > modules, so why was that an issue? >> >> I believe you meant, "why was that *not* an issue?". > >Right. > >> In ksymtab, namespaced symbols had the format >> >> __ksymtab_. >> >> while symbols without namespace would still use the old format >> >> __ksymtab_ > >Ah, I didn't see the symbol namespace patches, good stuff! > >> These are also the names that are extracted into System.map (using >> scripts/mksysmap). Depmod is reading the System.map and for symbols used >> by modules that are in a namespace, it would not find a match as it does >> not understand the namespace notation. Depmod would still not emit a >> warning for symbols without namespace as their format did not change. > >Can we have a test case for this to ensure we don't regress on this >again? Or put another way, what test cases were implemented for symbol >namespaces? While modpost and kernel/module.c are the tests at build and runtime resp. to enforce proper use of symbol namespaces, I could imagine to test for the proper layout in the ksymtab entries (note, as mentioned earlier there are some fixes in flight to finalize the layout). In addition, I could imagine adding a test that tries to load a module that uses symbols from a namespace without importing it. The kernel should deny loading or complain about it (depending on the configuration). These are also some of the test cases I had when working on that feature. I did not implement these as automated tests though. I will put that on my list but help with that would be very welcome. Cheers, Matthias