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 2027BC46467 for ; Mon, 16 Jan 2023 18:09:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232419AbjAPSJv (ORCPT ); Mon, 16 Jan 2023 13:09:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232403AbjAPSJb (ORCPT ); Mon, 16 Jan 2023 13:09:31 -0500 Received: from mail-il1-x12c.google.com (mail-il1-x12c.google.com [IPv6:2607:f8b0:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE1503E629 for ; Mon, 16 Jan 2023 09:54:22 -0800 (PST) Received: by mail-il1-x12c.google.com with SMTP id v6so4750352ilq.3 for ; Mon, 16 Jan 2023 09:54:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=JPvljqvM2UcSP9Cl25a35r4uBDsPl3z3yfdTzXuhKNM=; b=rlz7btLcACEU80xL0e/C59u2bKVTZryWa5AQ20uRanoDuGuKQdfkqzAHQRF9yLcuV7 XuMHUAppqoVc3mM3cqpGnzYcjpKcFAdxqCBTLEdl8DTygEjEwLtrrh2sAhLM9vX2OXM9 LC2O5rEbSk73khV3qGnoh4VL131c+/1ZxEpca+YbzrF9q2a3Zoh8OADbvkOKNlJ23w2p 4TV3WFm0N04bSPJST584/12NhGsjWtL1IL70zpPU+vR+tHZNo0Xx19ZIlsXVBjQjkQsP KxIjujm144pK0Fr8SY+K4s7sbL9twCtnouax72sKga7TAY1xmygNY6PpHvoLotQLbz8p v/dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=JPvljqvM2UcSP9Cl25a35r4uBDsPl3z3yfdTzXuhKNM=; b=VOWwrIYPQy6o8UdlpRG1DNH8zRWSc7LswiY+pfGOTSS7h+rrryCHWdipTPLRCyQDY7 e3drKd5fui492NYtd8m6E4emSsM23szEB0egct35CFvJi1WcDsnXU+y6ANbOBcWjO5Wq Vrj4+y1jGVcC/6W/27r6BqBO86/i9VR/mLR8hwtLNSa56hZ4tt7jWWJXlWWNEAA+R0hP OnnsY6ZGH2oxQlPigB2p7JQ/GETpcQ0byGBFfwPE0rAqT9HrWOISbKwAQWSg8pSptvpE REoIjPAdiiGPgrrwdEBMjcAXT81hFWCVue987sdX2RnQ7NUKhbt+L5KX0FeWUNsjl5rE Qpfg== X-Gm-Message-State: AFqh2kpHizZ5rjMaTz4jGnRdTbraMIgiNP3ztbDdu3EgHa/rwLiaAzXu pdl3W+Jb2LHjYwLHw+qIux5oU/F7Zl8uSFO9v6U17g== X-Google-Smtp-Source: AMrXdXsLqods1YxC3Cdh8Nt6GJ+RJ9rixb59lYOUT7kPVWwVsWv9Dlkp5l/zGgwJk2awF24rofhYJ/6fvFpzd62JM6U= X-Received: by 2002:a05:6e02:5c3:b0:30c:33da:cb53 with SMTP id l3-20020a056e0205c300b0030c33dacb53mr27850ils.173.1673891647618; Mon, 16 Jan 2023 09:54:07 -0800 (PST) MIME-Version: 1.0 References: <000000000000e259c105f25c92da@google.com> In-Reply-To: <000000000000e259c105f25c92da@google.com> From: Jann Horn Date: Mon, 16 Jan 2023 18:53:31 +0100 Message-ID: Subject: Re: [syzbot] WARNING: refcount bug in mm_update_next_owner To: syzbot , Jens Axboe , Pavel Begunkov , io-uring Cc: akpm@linux-foundation.org, arnd@arndb.de, brauner@kernel.org, ebiederm@xmission.com, keescook@chromium.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org All 5 console logs listed on the syzkaller dashboard for this one have io-uring with IORING_OP_POLL_ADD somewhere. Could that be related? On Mon, Jan 16, 2023 at 8:31 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 0a093b2893c7 Add linux-next specific files for 20230112 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=16a8e102480000 > kernel config: https://syzkaller.appspot.com/x/.config?x=835f3591019836d5 > dashboard link: https://syzkaller.appspot.com/bug?extid=1d4c86ac0fed92e3fc78 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/8111a570d6cb/disk-0a093b28.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/ecc135b7fc9a/vmlinux-0a093b28.xz > kernel image: https://storage.googleapis.com/syzbot-assets/ca8d73b446ea/bzImage-0a093b28.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+1d4c86ac0fed92e3fc78@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > refcount_t: addition on 0; use-after-free. > WARNING: CPU: 0 PID: 5316 at lib/refcount.c:25 refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 > Modules linked in: > CPU: 0 PID: 5316 Comm: syz-executor.4 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 > RIP: 0010:refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 > Code: 0a 31 ff 89 de e8 d4 13 78 fd 84 db 0f 85 2e ff ff ff e8 57 17 78 fd 48 c7 c7 60 87 a6 8a c6 05 e0 ce 54 0a 01 e8 98 a7 b2 05 <0f> 0b e9 0f ff ff ff e8 38 17 78 fd 0f b6 1d ca ce 54 0a 31 ff 89 > RSP: 0018:ffffc90005967d80 EFLAGS: 00010286 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff8880829f3a80 RSI: ffffffff8166972c RDI: fffff52000b2cfa2 > RBP: ffff888082ae3aa8 R08: 0000000000000005 R09: 0000000000000000 > R10: 0000000000000001 R11: 0000000000000000 R12: ffff88807e520900 > R13: ffff888082ae3fa8 R14: 0000000000000000 R15: ffff888082ae3aa8 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b32f23000 CR3: 000000007716c000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > __refcount_add include/linux/refcount.h:199 [inline] > __refcount_inc include/linux/refcount.h:250 [inline] > refcount_inc include/linux/refcount.h:267 [inline] > get_task_struct include/linux/sched/task.h:110 [inline] > mm_update_next_owner+0x585/0x7b0 kernel/exit.c:504 > exit_mm kernel/exit.c:562 [inline] > do_exit+0x9a4/0x2a90 kernel/exit.c:854 > do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 > __do_sys_exit_group kernel/exit.c:1023 [inline] > __se_sys_exit_group kernel/exit.c:1021 [inline] > __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1021 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f51f5a8c0c9 > Code: Unable to access opcode bytes at 0x7f51f5a8c09f. > RSP: 002b:00007ffe3c730ad8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > RAX: ffffffffffffffda RBX: 000000000000001e RCX: 00007f51f5a8c0c9 > RDX: 00007f51f5a3df7b RSI: ffffffffffffffb8 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 000000002ed3101e R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffe3c730bc0 > > > > --- > 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.