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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07440C54E5D for ; Mon, 18 Mar 2024 21:15:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 92CF18E0007; Mon, 18 Mar 2024 17:15:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8DCF18E0003; Mon, 18 Mar 2024 17:15:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 77E2F8E0007; Mon, 18 Mar 2024 17:15:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 626768E0003 for ; Mon, 18 Mar 2024 17:15:58 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id D83111606DD for ; Mon, 18 Mar 2024 21:15:57 +0000 (UTC) X-FDA: 81911417154.02.7A56D23 Received: from mail-vk1-f177.google.com (mail-vk1-f177.google.com [209.85.221.177]) by imf19.hostedemail.com (Postfix) with ESMTP id 0CE821A0009 for ; Mon, 18 Mar 2024 21:15:55 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=XkvtMHKa; spf=pass (imf19.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.177 as permitted sender) smtp.mailfrom=21cnbao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1710796556; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=nNvrtsGjVTtu6R10uTVM8kPeIVOJpDjIQh7MdUQaOu8=; b=I3PFqTheffA1p/qkHHFlazp6IvMwlZ01P1rOyT2VVy/fUCKYPoBfn8e+lQAzZ0O0/ubWef b5EWkY+ojEn7e4cqwNN16YMiaUo+n7MDST+mJY8rXpTmRH85MtgyAQcwgLvXG+uhbFty3i 73mgetsRU9/0LgJs5IMPbuZPc6HbaUs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1710796556; a=rsa-sha256; cv=none; b=h6fcBcc+Pbw5ZZRlAr/MKlmVyfgXaK3aphwBdNGKytIE9cehGl24lYzK46+QaWgy4LTGbK vplXx9jy2Gu4ssIH/ET/G+eLww9Jelb9AzrVTNR0wS0lBcyRtc1qWlEbVOwVllJQ1Q1Mo8 5e5CiCrVsFNoFUSC1RCZe8ahG3z9uOI= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=XkvtMHKa; spf=pass (imf19.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.177 as permitted sender) smtp.mailfrom=21cnbao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-vk1-f177.google.com with SMTP id 71dfb90a1353d-4d43d602cd6so760651e0c.0 for ; Mon, 18 Mar 2024 14:15:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1710796555; x=1711401355; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=nNvrtsGjVTtu6R10uTVM8kPeIVOJpDjIQh7MdUQaOu8=; b=XkvtMHKaXpfDG/xwFWCBb6RUCmW6bm+me54WbfdCIgQK13xEffPQhBKiTjeBUpOLLc vHBly5XHDllt+o2ZP1haanR+tGVqgiXApqkdiI213ta4/mBqXjGp6+iuBaeEoNsysriD MU83BASrJzW+XS/N7Ngu15kjGSZiE/CZ58qaLTLJ5oIzxeNxGEPnnkjGYrUL5BkmorsT hNaw4VpIaLALGxpP9xXrINdA52Y8GKFduep0kqhmji9aZhX0FxadJ3UIk7uZHm8/eHP4 k/rFlanh2UK3lTyAEv7OSWZj+85843rRetUn4e9L4qdKGtCgB3z5k/u+nW4dHgBzWwdI LWKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710796555; x=1711401355; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nNvrtsGjVTtu6R10uTVM8kPeIVOJpDjIQh7MdUQaOu8=; b=WrYHcV87x+1CDuPUM52e9cCiutznx0TCilN4v++66RHKT3BEWUaj0TD6ycGbYfgJR2 cQLes+d3941axv6PvXmiUt3JD+41xT97csW1tpsXkcM3og0HDVbtHW1xwTyxDQ8kM0LF tYltOW6HpOu9UKlDeYwNiOWxvGw/WSn55wVN6g/8F6ing60nwGpFzEL2xbk9sYNuaap+ 8wwcNqConI5w2TPsuKyuUtCGJ+1yNQNcf+0yVmtiB/mYQ4F0cY+WqpRG8wKGQ+9WQwVv 0as4eZiZVujgKYgxALWpRshH4LJJShZul0oRY+FnYuTjkapFgMP/S3REQr1LTVwzyb2z lpsg== X-Forwarded-Encrypted: i=1; AJvYcCXNIdACECWjOhj60eJW6bSIuKh4YR+0/f4fM6ZlDGErPQAOrdlXVm7Qab5dXdZpnn6iXHibp5NwEqV4TNXfNlm0iGA= X-Gm-Message-State: AOJu0YwgFdSk+I/EYR3YxYSO5nhb3O6WuI6gEjzCeHl2OtnIa4Gkn+PL Lj86x4omefBGnBqy85T+H9+y/gj74LXmxX2cH+xfAn92G4oFVFcT5uA0Rrub07VUhJO7BIiF1kp Gd7Yhn+Kj4+VVR1K+/AUIIc1iKhw= X-Google-Smtp-Source: AGHT+IFmYQMKApHO/ktNoo3RDcDuEbq/bJLEEAHMN6ZUPVI+ASpbKfIxUcIaLVFgE8DmvO37qMZVP5Kn4XFr2z0cA0M= X-Received: by 2002:a1f:7dcf:0:b0:4d3:4aad:22d4 with SMTP id y198-20020a1f7dcf000000b004d34aad22d4mr8349994vkc.0.1710796555068; Mon, 18 Mar 2024 14:15:55 -0700 (PDT) MIME-Version: 1.0 References: <000000000000bbb3d80613f243a6@google.com> <20240318210917.GA4210@cmpxchg.org> In-Reply-To: <20240318210917.GA4210@cmpxchg.org> From: Barry Song <21cnbao@gmail.com> Date: Tue, 19 Mar 2024 10:15:43 +1300 Message-ID: Subject: Re: [syzbot] [mm?] kernel BUG in sg_init_one To: Johannes Weiner Cc: Yosry Ahmed , Nhat Pham , syzbot , akpm@linux-foundation.org, chengming.zhou@linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, Barry Song Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 0CE821A0009 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 1nwck9takxbb6eyz9s8kkqfqcqs3sz74 X-HE-Tag: 1710796555-400005 X-HE-Meta: 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 JORWkxZn 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 LlqTqnG6 mDziFzTiXc2dd1jMLzgdRWKXErLiXXRG8M1d054T/2wPkX5eX/0RhYbRBqG/ZPjoFag482nYDhk= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Mar 19, 2024 at 10:10=E2=80=AFAM Johannes Weiner wrote: > > On Mon, Mar 18, 2024 at 01:17:19PM -0700, Yosry Ahmed wrote: > > On Mon, Mar 18, 2024 at 11:00=E2=80=AFAM Nhat Pham = wrote: > > > > > > On Mon, Mar 18, 2024 at 9:58=E2=80=AFAM syzbot > > > wrote: > > > > > > > > Hello, > > > > > > > > syzbot found the following issue on: > > > > > > > > HEAD commit: e5eb28f6d1af Merge tag 'mm-nonmm-stable-2024-03-14-= 09-36' .. > > > > git tree: upstream > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D13043ab= e180000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=3D19bb57c= 23dffc38e > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=3Dadbc983a1= 588b7805de3 > > > > compiler: arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GN= U ld (GNU Binutils for Debian) 2.40 > > > > userspace arch: arm > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=3D1706d= 231180000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D13ba795= 9180000 > > > > > > > > Downloadable assets: > > > > disk image (non-bootable): https://storage.googleapis.com/syzbot-as= sets/8ead8862021c/non_bootable_disk-e5eb28f6.raw.xz > > > > vmlinux: https://storage.googleapis.com/syzbot-assets/0a7371c63ff2/= vmlinux-e5eb28f6.xz > > > > kernel image: https://storage.googleapis.com/syzbot-assets/7539441b= 4add/zImage-e5eb28f6.xz > > > > > > > > IMPORTANT: if you fix the issue, please add the following tag to th= e commit: > > > > Reported-by: syzbot+adbc983a1588b7805de3@syzkaller.appspotmail.com > > > > > > > > ------------[ cut here ]------------ > > > > kernel BUG at include/linux/scatterlist.h:187! > > > > > > Looks like the provided buffer is invalid: > > > > > > #ifdef CONFIG_DEBUG_SG > > > BUG_ON(!virt_addr_valid(buf)); > > > #endif > > > > > > which is "src" from: > > > > > > sg_init_one(&input, src, entry->length); > > > > > > Looking at the surrounding code and recent history, there's this > > > commit that stands out: > > > > > > mm/zswap: remove the memcpy if acomp is not sleepable > > > (sha: 270700dd06ca41a4779c19eb46608f076bb7d40e) > > > > > > which has the effect of, IIUC, using the zpool mapped memory directly > > > as src, instead of acomp_ctx->buffer (which was previously the case, > > > as zsmalloc was not sleepable). > > > > > > This might not necessarily be a bug with that commit itself, but migh= t > > > have revealed another bug elsewhere. > > > > > > Anyway, cc-ing the author, Barry Song, to fact check me :) Will take = a > > > closer look later. > > > > I am not a highmem expert, but the reproducer has CONFIG_HIGHMEM=3Dy, > > and it seems like zs_map_object() may return a highmem address if the > > compressed object is entirely in a single page to avoid copying to a > > buffer: > > > > if (off + class->size <=3D PAGE_SIZE) { > > /* this object is contained entirely within a page */ > > area->vm_addr =3D kmap_atomic(page); > > ret =3D area->vm_addr + off; > > goto out; > > } > > > > The virt_addr_valid() check seems to indicate that we expect a direct > > map address in sg_init_one(), right? > > If the page is highmem, kmap_atomic() establishes a temporary mapping > to it in the direct map, such that we have a legit kernel pointer to > the memory. Otherwise the memcpy() in zswap also wouldn't work... Am I > missing something? Right, we built a map but it is not a linear mapping. so we can't use virt_to_page on this kind of non-linear mapping. kmap_to_page can handle both linear and non-linear, but Ira's commit added a WARN_ON_ONCE in it for non-linear mapping case.