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=-3.7 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 1E127C43457 for ; Fri, 16 Oct 2020 08:12:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4B4620829 for ; Fri, 16 Oct 2020 08:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405002AbgJPIMq (ORCPT ); Fri, 16 Oct 2020 04:12:46 -0400 Received: from mail-il1-f198.google.com ([209.85.166.198]:39047 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405072AbgJPIM0 (ORCPT ); Fri, 16 Oct 2020 04:12:26 -0400 Received: by mail-il1-f198.google.com with SMTP id b6so1013309ilm.6 for ; Fri, 16 Oct 2020 01:12:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=Bm5SWSSR+OsZVNyMrrEA80pp6Iujuo2nZZDiousUxIE=; b=iXe5mVlKVNFIHGDMZpJEw8WBmsk3Ym8vqzJ/tlcJRRsGIHmvNMrKSWdnGrZF0OKbgU v256IPpETE+xXzgYusmFwKofbGc85uD/4IbKIWeOFKIc3AiJGsCg9rjGDZzFkVDxqYK/ J2YYje8DLcfwqhAtCkNBCcOt+CpgsbuAZ9P+3xK7uYNNuIB19HPJS5L+PYpd4EfoSdmC bOR3lKj00z9H3UKnOvH579ExCIf+Kd+k5xmGAx9tDaVrU+qtF3RnqbK2iNA4cDfheEUC JbnhwKV7/HNtgoEzXcj1pIzbP2+U4smyGQAPL99Jy+c/F5UAf0PjLZrYYq/o46lDHusv TPdw== X-Gm-Message-State: AOAM5300QwUVkIPBjViqctipakh1+zCgGdkQCWG6dTBgoKkZP78i8HKd bxa2MXOD+nIGZQ+tggG2KgquMMaC5+14tmzFm6lUpBuBYeaY X-Google-Smtp-Source: ABdhPJy3LJBD6x/8VkyDz94aY18nGxniV6nVha/uNNH6Dza+BQ6D5uZ0J9EKSFEFuqaj/qAA0FDyTdaa7Rr/9N4BWuttro+XA9Ui MIME-Version: 1.0 X-Received: by 2002:a6b:651a:: with SMTP id z26mr1572620iob.186.1602835943793; Fri, 16 Oct 2020 01:12:23 -0700 (PDT) Date: Fri, 16 Oct 2020 01:12:23 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000010295205b1c553d5@google.com> Subject: WARNING: suspicious RCU usage in io_init_identity From: syzbot To: axboe@kernel.dk, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: b2926c10 Add linux-next specific files for 20201016 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=12fc877f900000 kernel config: https://syzkaller.appspot.com/x/.config?x=6160209582f55fb1 dashboard link: https://syzkaller.appspot.com/bug?extid=4596e1fcf98efa7d1745 compiler: gcc (GCC) 10.1.0-syz 20200507 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+4596e1fcf98efa7d1745@syzkaller.appspotmail.com ============================= WARNING: suspicious RCU usage 5.9.0-next-20201016-syzkaller #0 Not tainted ----------------------------- include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor.0/8301. stack backtrace: CPU: 0 PID: 8301 Comm: syz-executor.0 Not tainted 5.9.0-next-20201016-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fb lib/dump_stack.c:118 task_css include/linux/cgroup.h:494 [inline] blkcg_css include/linux/blk-cgroup.h:224 [inline] blkcg_css include/linux/blk-cgroup.h:217 [inline] io_init_identity+0x3a9/0x450 fs/io_uring.c:1052 io_uring_alloc_task_context+0x176/0x250 fs/io_uring.c:7730 io_uring_add_task_file+0x10d/0x180 fs/io_uring.c:8653 io_uring_get_fd fs/io_uring.c:9144 [inline] io_uring_create fs/io_uring.c:9308 [inline] io_uring_setup+0x2727/0x3660 fs/io_uring.c:9342 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de59 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7e11fe1bf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 000000000045de59 RDX: 00000000206d4000 RSI: 0000000020000080 RDI: 0000000000000087 RBP: 000000000118c020 R08: 0000000020000040 R09: 0000000020000040 R10: 0000000020000000 R11: 0000000000000206 R12: 00000000206d4000 R13: 0000000020ee7000 R14: 0000000020000040 R15: 0000000020000000 --- 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.