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 08731CF9C6E for ; Mon, 23 Sep 2024 11:58:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 28EF26B007B; Mon, 23 Sep 2024 07:58:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 23EFB6B0083; Mon, 23 Sep 2024 07:58:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 106926B0085; Mon, 23 Sep 2024 07:58:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id E83206B007B for ; Mon, 23 Sep 2024 07:58:37 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 69B3641327 for ; Mon, 23 Sep 2024 11:58:37 +0000 (UTC) X-FDA: 82595855874.05.7EAC7FF Received: from mail-pf1-f174.google.com (mail-pf1-f174.google.com [209.85.210.174]) by imf18.hostedemail.com (Postfix) with ESMTP id 8306C1C0018 for ; Mon, 23 Sep 2024 11:58:35 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=F8Q602UC; spf=pass (imf18.hostedemail.com: domain of elver@google.com designates 209.85.210.174 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1727092656; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=iOy3F5UhYdO07lOzBiN5XGBdBxeYkWOi12G5NHF9q4U=; b=Tv7o3Zlfz+VtKwsMbTt9K9FSfI7GXCITPVx999jU6pO27pb/zzccoCGAR2fGByMgBNvsed 1iOZmPlnTVkfPastvixhJE7ttpWUuixtFtMive4yPR1pJwRuoUtFJ6ERVH9WznT2DlpLTU fgs/Yavq9XoVs1JNxiIElAXTQCYhcZY= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=F8Q602UC; spf=pass (imf18.hostedemail.com: domain of elver@google.com designates 209.85.210.174 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1727092656; a=rsa-sha256; cv=none; b=5QrJE8yK8jWypBsMEllCWE7dq/XykgF+29wwsgG/AJS8vGvsnYUYyv4qaEXBfNH4hvHMXd wxXJ1O46PiVmzfejGjdyDqXXZ566BJnWrcKUMoMB9508Lk/7/yijLJ0HuHNR4VvIg0VD+3 5A+eIz13OCRtrJZ6UpLOg43e0Htqv5c= Received: by mail-pf1-f174.google.com with SMTP id d2e1a72fcca58-718d8d6af8fso3024354b3a.3 for ; Mon, 23 Sep 2024 04:58:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727092714; x=1727697514; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=iOy3F5UhYdO07lOzBiN5XGBdBxeYkWOi12G5NHF9q4U=; b=F8Q602UCwB9oU+V5eLxG/WD8nShPbsNAy7ErPC4EpxVAgwhAJ8SrqroLyGeGZ9dF4w DR/WvILKe9m14z0ZPVFK/Powor7VECu00MyA06EQLjsiiZTfYu2hfhWQ8mQ8OYXwUqiV 7pQAVUYeciYbSrHyJhDgKpq3XFowSA226Ge9GdOjH14bp2sXhb2ISaaLwLI+snzB+pS+ 2VfuuZvgpyw4PTikbZcr/Klf+qdEbcKc4vY07EIy0SITNzSIQs2BZa3jWfmw2O9kbUIm 26Xy83ziCmgEdYXfE1ITSu49DIREkuZuX69ZXUKHMtA7wiyZUuKKiIOAP1e4wAjgaTf3 I7dQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727092714; x=1727697514; h=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=iOy3F5UhYdO07lOzBiN5XGBdBxeYkWOi12G5NHF9q4U=; b=UPBeu/FAtBG1vl61mHrIS3ZAYNwegi6VtIMeWGZ9M268ADvnRF5R3uSaDeuDzaWHl/ dYQRVzSJxLb99M32OJo5UKa5JgIOWEYzqdOIxkXMelRB6OazsUIWuDdQAEbdSkXrZ4wm l9i254aIMueGfexu4H4GNmKoNIUFf5ECN44AquVWbGHljVUmQKdqd+H15cE81+UAeLhN VsdBnzjH+mUhnCpxfg18Rk/FMOwP9QZUlmDYwWQLlTJ6xcrXWz677bm+bHJMtRb3nLsK MgAL+koMVKBUAfgjbQJIIMgNB37cHdMLGYpeHsJ0DFnU7btfVQ/J0zrcqjL7zAFRJ0r4 di1g== X-Forwarded-Encrypted: i=1; AJvYcCXxeSAeyGB6F6aW4WHTr2Sd/QuwaSJ1De4FB+1e15ihBt1BztpoqyUhF3OOgoppFy1N/FNTihOaOw==@kvack.org X-Gm-Message-State: AOJu0YyRz4OAxjpKHs4uQKLaEGPwb6mXwUndLVYLgw2boMVY3T8BvwXl JbKFqXvEVjDU8qraD4DSM6Dl8318S/oIjXnlaAaavnBu3qb/KHV/ucrkEXlF/Nrg4FLCGUsyQMQ KIsJUDP9xBd6HYmzQoKncTk1M9BK5x72dma1I X-Google-Smtp-Source: AGHT+IGIFobrvHy+AXM4qlo3wITiio8U/9zcHky3RTDkeEk0vlFYGkf2d/eaT8VNYEdS9qlTVubA/rTK6i98CSYi410= X-Received: by 2002:a05:6a00:2d91:b0:717:fd98:4a6 with SMTP id d2e1a72fcca58-7199c990e08mr16661821b3a.11.1727092713634; Mon, 23 Sep 2024 04:58:33 -0700 (PDT) MIME-Version: 1.0 References: <66f12f17.050a0220.3eed3.000b.GAE@google.com> <53e80bb1-9d26-4885-81fd-6fe816b4980b@lucifer.local> In-Reply-To: <53e80bb1-9d26-4885-81fd-6fe816b4980b@lucifer.local> From: Marco Elver Date: Mon, 23 Sep 2024 13:57:55 +0200 Message-ID: Subject: Re: [syzbot] [mm?] KCSAN: data-race in mas_wr_store_entry / mtree_range_walk To: Lorenzo Stoakes Cc: syzbot , Liam.Howlett@oracle.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, vbabka@suse.cz Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 8306C1C0018 X-Stat-Signature: esqxd315xddz7bkuwgmijc7okx94b4zu X-HE-Tag: 1727092715-873619 X-HE-Meta: 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 bidLhPMG 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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 Mon, 23 Sept 2024 at 11:44, 'Lorenzo Stoakes' via syzkaller-bugs wrote: > > On Mon, Sep 23, 2024 at 02:04:23AM GMT, syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 88264981f208 Merge tag 'sched_ext-for-6.12' of git://git.k.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1237ec27980000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=e6702f5f2b8ed242 > > dashboard link: https://syzkaller.appspot.com/bug?extid=e01fa33e67abb0b3b3bb > > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > > > Thanks for the report, investigating. > > > Unfortunately, I don't have any reproducer for this issue yet. > > I suspect given this is so timing-specific, a reproducer might be difficult. FWIW, syzbot currently does not try to find reproducers for KCSAN, because it's too non-deterministic. The best strategy would be for a developer who has an intuition for what might be going on to create a stress-test to reproduce. > This suggests we are failing to acquire an RCU lock on mmap() (though we > have the write mmap lock). > > Maybe we missed an RCU lock at some point, but I'm a little baffled as to > what could have changed in recent series to adjust this. > > I will dig into this and see what's going on. Thanks!