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 88354C4828F for ; Sun, 4 Feb 2024 02:59:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C82936B0074; Sat, 3 Feb 2024 21:59:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C32E06B0075; Sat, 3 Feb 2024 21:59:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AFA5E6B0078; Sat, 3 Feb 2024 21:59:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A10A26B0074 for ; Sat, 3 Feb 2024 21:59:40 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 63DC3802DE for ; Sun, 4 Feb 2024 02:59:40 +0000 (UTC) X-FDA: 81752616120.15.7F8CE3B Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) by imf30.hostedemail.com (Postfix) with ESMTP id 691AF80009 for ; Sun, 4 Feb 2024 02:59:38 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=vB6EymuB; spf=pass (imf30.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.188 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707015578; 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=ZtQLtcv75Hp76wlNnxYlPTsE3iyYS6NrvoUGxNyUIs4=; b=1uvQKhaC63iUGXA9Kz1Own+feQkmbSlUAvK8dc4H/m085GocpuEIitUFnfs7apmZU89pmy y3yyn5RVsTXwane0Xi0fm2SKlX7C1EihtGBl5DAKyK3m6qexBs6dYATyr/gBVnDit2gq2D 8vvju6uSdzP+T7bAwG6d7yDq7flK2Ew= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707015578; a=rsa-sha256; cv=none; b=i66HTzL7inj8ujuJSIbbRKmFJSL8bzm8o6nkyny7FHZ+VfOkQ8zZNJUmf3F888+BVF0Thg 7p0Kc+6y8af/DV+QjHswmU9Q7cQToAv9D0gePBceGqfH9N1ZWmQ64hEuZtHJHfVjCAhcrx oxD2Xf5P7/D2VCjd62kKK9JMedssdDg= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=vB6EymuB; spf=pass (imf30.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.188 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: <5ea0950d-1b2e-47ae-b8a0-8bc0e99479f1@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1707015576; h=from:from: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; bh=ZtQLtcv75Hp76wlNnxYlPTsE3iyYS6NrvoUGxNyUIs4=; b=vB6EymuB3TpJMhRRntrC59cd5US6NXdH/dlN7iHTxlXCPlB9iJnsbaialYBRgO1aTgHzYs 8RERJmfdF47juRBaMoIA4gHAlklWEe6JQvmTrhu3TsGWBCL1fX4gzBNaWZCE5oRXLg/VKb ELW5yF96K/30cmNq+KGfqTTOCPWAkCs= Date: Sun, 4 Feb 2024 10:59:22 +0800 MIME-Version: 1.0 Subject: Re: [syzbot] [mm?] WARNING in zswap_folio_swapin Content-Language: en-US To: Nhat Pham , syzbot Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, yosryahmed@google.com References: <000000000000ae47f90610803260@google.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 691AF80009 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: e8phgc3mi3r945zobt31jar5heopyxy3 X-HE-Tag: 1707015578-728356 X-HE-Meta: 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 0Vk9+oi8 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 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 2024/2/4 09:28, Nhat Pham wrote: > On Sat, Feb 3, 2024 at 12:37 PM syzbot > wrote: >> >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 861c0981648f Merge tag 'jfs-6.8-rc3' of github.com:kleikam.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=174537bbe80000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=b168fa511db3ca08 >> dashboard link: https://syzkaller.appspot.com/bug?extid=17a611d10af7d18a7092 >> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 >> userspace arch: i386 >> >> Unfortunately, I don't have any reproducer for this issue yet. >> >> Downloadable assets: >> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-861c0981.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/b2b204c7b4a0/vmlinux-861c0981.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/170ec316e557/bzImage-861c0981.xz >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+17a611d10af7d18a7092@syzkaller.appspotmail.com >> >> kcov_ioctl+0x4f/0x720 kernel/kcov.c:704 >> __do_compat_sys_ioctl+0x2bf/0x330 fs/ioctl.c:971 >> do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] >> __do_fast_syscall_32+0x79/0x110 arch/x86/entry/common.c:321 >> page has been migrated, last migrate reason: compaction >> ------------[ cut here ]------------ >> WARNING: CPU: 2 PID: 5104 at include/linux/memcontrol.h:775 folio_lruvec include/linux/memcontrol.h:775 [inline] >> WARNING: CPU: 2 PID: 5104 at include/linux/memcontrol.h:775 zswap_folio_swapin+0x47d/0x5a0 mm/zswap.c:381 >> Modules linked in: >> CPU: 2 PID: 5104 Comm: syz-fuzzer Not tainted 6.8.0-rc2-syzkaller-00031-g861c0981648f #0 >> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 >> RIP: 0010:folio_lruvec include/linux/memcontrol.h:775 [inline] > > Hmm looks like it's this line: > VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled(), folio); > > Looks like memcg was cleared from the folio. Haven't looked too > closely yet, but this (and the "page has been migrated" line above) > suggests maybe there is some migration business going on - > mem_cgroup_migrate() clears the old folio's memcg_data (via > old->memcg_data = 0). Yeah, I think it's this case. > > Here's my theory (which could be wrong - someone please fact-check > me): swap_read_folio(), which precedes zswap_folio_swapin(), unlocks And another case is !page_allocated, the returned folio is unlocked, right? > the folio. Could this be sufficient to allow for migration? If this is IMHO, folio locked is sufficient to avoid concurrent memcg migration. > the case, all we need to do is move this to above swap_read_folio(), > while the folio is still locked. __read_swap_cache_async() already > charges the folio to an memcg, so no need to wait till after > swap_read_page() anyway. Should we call zswap_folio_swapin() in the !page_allocated case? Thanks.