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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=ham 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 278A8C433B4 for ; Tue, 13 Apr 2021 18:11:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4EFB613B6 for ; Tue, 13 Apr 2021 18:11:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347520AbhDMSLe (ORCPT ); Tue, 13 Apr 2021 14:11:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231187AbhDMSLd (ORCPT ); Tue, 13 Apr 2021 14:11:33 -0400 Received: from mail-qv1-xf2b.google.com (mail-qv1-xf2b.google.com [IPv6:2607:f8b0:4864:20::f2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 269E0C061574 for ; Tue, 13 Apr 2021 11:11:13 -0700 (PDT) Received: by mail-qv1-xf2b.google.com with SMTP id ef17so2873179qvb.0 for ; Tue, 13 Apr 2021 11:11:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EbjN2qgyylIxptriBP8xjTcrzsIUK7NPVHheYkzWTx0=; b=SFNBkVAI8DgbvH8Q8/yBgc6VSKWr6iYyV9eWCOLzMMKWSAa4VeCylORFe3v+FRs7Tf sw5e1oDUIrBKKy25tfxXUQ29vC6mhaMygokMsOn2JA1gKLSiseAbhYrpOyfFz/yydKfw /yPh8RoN4qh7B7EE04p09qdj5WES57g/XI4kszQR053Mhr3+CySNRkxPMOkWGHfZLa3x xeA/iVH0LF8vXOdzGdBvyZukrhnQvJaYnI5gk8y9xzQ4m62fo+PoB+7XiriAfInAeh9+ kbaPROT0k6V1BvZvj3UH+I6ZzkoSgpkbpBLUlCVZ1wycGqYMtpPFnBciJEd6y+lhsqcP zydg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=EbjN2qgyylIxptriBP8xjTcrzsIUK7NPVHheYkzWTx0=; b=TIekL7vjR8XAPT7teu8IFTrfjZXYQZOEli5WEkRawa8kelAhM5tFxXtzmzoRtMy066 kThJnOgGy7t7WbMC2uT3oUn1by89juF6e4AXKlqM9dK2M5LV/V9EJdsXVgmGmkjc1iFp FYM7E/2OJxi2o1tGInBl92qcNHNUJSggEiY++Y/vfxRs1oNPh2nIDFYtW7RB+FPZw41T Jvc/WO+Ab9MTJZbk77nupyYO36+DsNYCjCsNHN/z9+nGY9r1b5CAcdtDrwPXWiE/wfiW 6CpFBsJO5rMy8zpJy791SbznIXCv0QXN0Uh2JjhxiQbgv/6TBha36fQ6rqOHGoiGhvq5 KczA== X-Gm-Message-State: AOAM531DJbbofEKMf74mA6ZoQqm18VBGFs1+dbYwEKa61hGjmbgWr467 FcpLNX2+91a8+uhd0FLQlS4uyz7QCXnLb5mxN5Qchw== X-Google-Smtp-Source: ABdhPJzBOLNJhkmbLNEil9eaU/PAi+m6VZdIIi+X0unvqFCGELJcwps6owjf+CXap57oql6GSNQsZljO+A0vYx5WCrE= X-Received: by 2002:a05:6214:3eb:: with SMTP id cf11mr2207324qvb.37.1618337472075; Tue, 13 Apr 2021 11:11:12 -0700 (PDT) MIME-Version: 1.0 References: <0000000000002bb2bd05bf3310db@google.com> In-Reply-To: <0000000000002bb2bd05bf3310db@google.com> From: Dmitry Vyukov Date: Tue, 13 Apr 2021 20:11:00 +0200 Message-ID: Subject: Re: [syzbot] WARNING: suspicious RCU usage in do_user_addr_fault To: syzbot Cc: Daniel Bristot de Oliveira , Benjamin Segall , dietmar.eggemann@arm.com, Juri Lelli , LKML , Mel Gorman , Ingo Molnar , Peter Zijlstra , Steven Rostedt , syzkaller-bugs , Vincent Guittot Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 5, 2021 at 7:35 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: d19cc4bf Merge tag 'trace-v5.12-rc5' of git://git.kernel.o.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17a22d16d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=78ef1d159159890 > dashboard link: https://syzkaller.appspot.com/bug?extid=3d5082ab6eec95ad4231 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+3d5082ab6eec95ad4231@syzkaller.appspotmail.com #syz dup: WARNING: suspicious RCU usage in getname_flags > WARNING: suspicious RCU usage > 5.12.0-rc5-syzkaller #0 Not tainted > ----------------------------- > kernel/sched/core.c:8294 Illegal context switch in RCU-bh read-side critical section! > > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 0 > 1 lock held by syz-executor.5/8582: > #0: ffff888029093218 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] > #0: ffff888029093218 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x285/0x1210 arch/x86/mm/fault.c:1331 > > stack backtrace: > CPU: 0 PID: 8582 Comm: syz-executor.5 Not tainted 5.12.0-rc5-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x141/0x1d7 lib/dump_stack.c:120 > ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8294 > do_user_addr_fault+0x2c2/0x1210 arch/x86/mm/fault.c:1348 > handle_page_fault arch/x86/mm/fault.c:1475 [inline] > exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531 > asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577 > RIP: 0033:0x406f13 > Code: 00 00 e8 a0 a1 ff ff 85 c0 74 4e 8b 54 24 0c 49 8b 37 31 c0 48 8d 3d 79 7f 0b 00 e8 27 c3 ff ff 8b 44 24 6c 49 8d 4f 60 89 de <4d> 89 a7 b8 00 00 00 ba 40 00 00 00 44 89 ef 41 89 87 b4 00 00 00 > RSP: 002b:00007fff2a8e7140 EFLAGS: 00010202 > RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000544420 > RDX: 0000000000000002 RSI: 0000000000000000 RDI: 00000000004bee7d > RBP: 00007fff2a8e7160 R08: 00007fff2a8e715c R09: 00007fff2a8e71f0 > R10: 00007fff2a8e71c0 R11: 0000000000000202 R12: 00007fff2a8e71c0 > R13: 0000000000000003 R14: 00007fff2a8e715c R15: 00000000005443c0 > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/0000000000002bb2bd05bf3310db%40google.com.