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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42631C38A02 for ; Mon, 31 Oct 2022 11:36:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230349AbiJaLgp (ORCPT ); Mon, 31 Oct 2022 07:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229628AbiJaLgm (ORCPT ); Mon, 31 Oct 2022 07:36:42 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0FFEE0A4 for ; Mon, 31 Oct 2022 04:36:41 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id e129so10437334pgc.9 for ; Mon, 31 Oct 2022 04:36:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=tk8T8KciNnKClZtt9a7oM7hEZLA8ALbiZujS1/Z8e40=; b=G53K5YU2JkveyKH2PbOn8K0UpNz0e894Cw6udPOu0c1h6+GqY5Pr/RdmUwR25EglGo dVr2iMlunxBMeCd7VlrfZ6FOqnpiIkFTAAWFBSl8Q4XAd+oQB/Dplv4mi0fUeni1/VSA f9bFtE4IRkYFEEa7yjr7imth2RhnTy3FvwawI9TSlIxH9uOrI94cDL04KBgGMBLIrtSv AVcKFyn++ITHCwWzIoHXrY5U4c8CXQGTnk6epkRhbjp5ss3lpRisch5j3fh8/oxJbzfE pNIuzd/lzEpSUpEqec7HqJAOVvTAs4uSf3lCBxm1oWnAucIg6xUZ64QAcLjrN52oe2NN ruRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=tk8T8KciNnKClZtt9a7oM7hEZLA8ALbiZujS1/Z8e40=; b=UFAyBOM5ByfemFo4XpURDWdchtPX3/gBMzA5fX7dEhO5Gwpwn6u1mSJlXIplSmM9eC Nrv61o0wbH0CNT0yKFx21mWEq3U2YR0fqK/yfS3k9yd5fLinZvHDlwVuuoxeQ+KBUlXu cUfSUwpx/94kS8wJwYXaXyBrPnbPTA+Ffq2BIjdFWuDq2rBMoCpFl2NHTLyOH15hHcRk u/+9IyNXPQT7NcvgkJ4ek17isJw1mBQK5g3+TinhiWWbWpRi0EjttPcTYV3VgRBKxhdM YMdbayxBdsz9MpMuCm3HKzND7hlrFJZuAIvP4746OiJPp1mwyGAXBjoSo56p98Zbbozr wYuQ== X-Gm-Message-State: ACrzQf0CqAv9Gse9Kv98pkpvfrmba54kiRcHmbClpLBVjLOyKKeIvwSF /vyv/BRWq/b7uNIRBGimylM= X-Google-Smtp-Source: AMsMyM4f8k2ljHcxbiskh8CAxXa8u4HJT5cN8F4TcPs0gPwUvckU0zmHtc1dUz4LmrD1ReEhoFGIeg== X-Received: by 2002:a05:6a00:14cc:b0:56b:9969:823 with SMTP id w12-20020a056a0014cc00b0056b99690823mr13659260pfu.36.1667216201343; Mon, 31 Oct 2022 04:36:41 -0700 (PDT) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id v17-20020aa799d1000000b0056bb191f176sm4526205pfi.14.2022.10.31.04.36.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Oct 2022 04:36:40 -0700 (PDT) Date: Mon, 31 Oct 2022 20:36:33 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: John Thomson Cc: Feng Tang , Vlastimil Babka , Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Dmitry Vyukov , Jonathan Corbet , Andrey Konovalov , "Hansen, Dave" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "kasan-dev@googlegroups.com" , Robin Murphy , John Garry , Kefeng Wang Subject: Re: [PATCH v6 1/4] mm/slub: enable debugging memory wasting of kmalloc Message-ID: References: <20220913065423.520159-1-feng.tang@intel.com> <20220913065423.520159-2-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 31, 2022 at 10:05:58AM +0000, John Thomson wrote: > On Mon, 31 Oct 2022, at 02:36, Feng Tang wrote: > > Hi John, > > > > Thanks for the bisecting and reporting! > > > > On Mon, Oct 31, 2022 at 05:30:24AM +0800, Vlastimil Babka wrote: > >> On 10/30/22 20:23, John Thomson wrote: > >> > On Tue, 13 Sep 2022, at 06:54, Feng Tang wrote: > >> >> kmalloc's API family is critical for mm, with one nature that it will > >> >> round up the request size to a fixed one (mostly power of 2). Say > >> >> when user requests memory for '2^n + 1' bytes, actually 2^(n+1) bytes > >> >> could be allocated, so in worst case, there is around 50% memory > >> >> space waste. > >> > > >> > > >> > I have a ralink mt7621 router running Openwrt, using the mips ZBOOT kernel, and appear to have bisected > >> > a very-nearly-clean kernel v6.1rc-2 boot issue to this commit. > >> > I have 3 commits atop 6.1-rc2: fix a ZBOOT compile error, use the Openwrt LZMA options, > >> > and enable DEBUG_ZBOOT for my platform. I am compiling my kernel within the Openwrt build system. > >> > No guarantees this is not due to something I am doing wrong, but any insight would be greatly appreciated. > >> > > >> > > >> > On UART, No indication of the (once extracted) kernel booting: > >> > > >> > transfer started ......................................... transfer ok, time=2.01s > >> > setting up elf image... OK > >> > jumping to kernel code > >> > zimage at: 80BA4100 810D4720 > >> > Uncompressing Linux at load address 80001000 > >> > Copy device tree to address 80B96EE0 > >> > Now, booting the kernel... > >> > >> It's weird that the commit would cause no output so early, SLUB code is > >> run only later. > > > > I noticed your cmdline has console setting, could you enable the > > earlyprintk in cmdline like "earlyprintk=ttyS0,115200" etc to see > > if there is more message printed out. > > Still nothing from vmlinux with earlykprint on UART unless revert. > > > > > Also I want to confirm this is a boot failure and not only a boot > > message missing. > > Yes, boot failure. > Network comes up automatically on successful boot. Not happening when no kernel UART It is really weird that I see no boot issue on my MIPS emulation with almost same config, with different target - Malta board that QEMU supports. it just boot fine. Can you attach debugger to the board? (Which I hadn't tried. I had tried it only to QEMU) [...] > >> > > >> > > >> > possibly relevant config options: > >> > grep -E '(SLUB|SLAB)' .config > >> > # SLAB allocator options > >> > # CONFIG_SLAB is not set > >> > CONFIG_SLUB=y > >> > CONFIG_SLAB_MERGE_DEFAULT=y > >> > # CONFIG_SLAB_FREELIST_RANDOM is not set > >> > # CONFIG_SLAB_FREELIST_HARDENED is not set > >> > # CONFIG_SLUB_STATS is not set > >> > CONFIG_SLUB_CPU_PARTIAL=y > >> > # end of SLAB allocator options > >> > # CONFIG_SLUB_DEBUG is not set > >> > >> Also not having CONFIG_SLUB_DEBUG enabled means most of the code the > >> patch/commit touches is not even active. > >> Could this be some miscompile or code layout change exposing some > >> different bug, hmm. > > Yes, it could be. What happens with clang? > > >> Is it any different if you do enable CONFIG_SLUB_DEBUG ? > > No change > > >> Or change to CONFIG_SLAB? (that would be really weird if not) > > This boots fine > > > I haven't found any clue from the code either, and I compiled > > kernel with the config above and tested booting on an Alder-lake > > desktop and a QEMU, which boot fine. > > > > Could you provide the full kernel config and demsg (in compressed > > format if you think it's too big), so we can check more? > > Attached > > > Thanks, > > Feng > > vmlinux is bigger, and entry point is larger (0x8074081c vs 0x807407dc revert vs 0x8073fcbc), > so that may be it? Or not? > revert + SLUB_DEBUG + SLUB_DEBUG_ON is bigger still, but does successfully boot. > vmlinux entry point is 0x8074705c > > > transfer started ......................................... transfer ok, time=2.01s > setting up elf image... OK > jumping to kernel code > zimage at: 80BA4100 810D6FA0 > Uncompressing Linux at load address 80001000 > Copy device tree to address 80B9EEE0 > Now, booting the kernel... > [ 0.000000] Linux version 6.1.0-rc2 (john@john) (mipsel-openwrt-linux-musl-gc > c (OpenWrt GCC 11.3.0 r19724+16-1521d5f453) 11.3.0, GNU ld (GNU Binutils) 2.37) > #0 SMP Fri Oct 28 03:48:10 2022 > > > I will keep looking. > > Thank you, > -- > John Thomson -- Thanks, Hyeonggon