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=-8.7 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 5A57CC433EF for ; Thu, 9 Sep 2021 00:10:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 367746109F for ; Thu, 9 Sep 2021 00:10:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348100AbhIIALh (ORCPT ); Wed, 8 Sep 2021 20:11:37 -0400 Received: from mail-io1-f71.google.com ([209.85.166.71]:56257 "EHLO mail-io1-f71.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244074AbhIIALh (ORCPT ); Wed, 8 Sep 2021 20:11:37 -0400 Received: by mail-io1-f71.google.com with SMTP id o128-20020a6bbe86000000b005bd06eaeca6so3261870iof.22 for ; Wed, 08 Sep 2021 17:10:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=oJITLq7oFNgdo+ig1paiTgEcP4D9oE5MGFM98vRAVnM=; b=inSYrM6kh1ky69R1ES2gFhbV9gxdsJ57xWJ225YdBvVWblnZwgzpj8duh/BacitOYL rbW92T3jvdycaDhpZ0+44pgNQhCehD0TgJV/i9W9aoGbcEFJshearQfBiHG4poKeI3WB OIYxFhgsfisvElW6qkWEAKmSot50IDJQtgMU/zkDBNTKYoKMQyf0enXWgd7+52LzoPWB ZkW+/BNGFrOFRJtBL3sTIy6dQI+cDWqsZ3W6DXlvRgsn7IoaUw8FDwAW2I8vS544ALFV qRKin8Cvi37GeDBQhr84ds034rf0tbXQF7of8Z+aQCNvWsSPc7k+fULUt/WZ9MZFGQPo hBgQ== X-Gm-Message-State: AOAM533U9T2ck7cc9EFA96QiEZE8GtsJTyxk2SrjLJx9cBREZDm8JGj2 lEaPPRGyqk43InY7BL+HF5XBnDZjEPS+bz1d/5CJ1J9jnYIJ X-Google-Smtp-Source: ABdhPJznLR+RDJNtDm1Mug+RCBx/rryN7gfcSgmfV9zCuSBBBtfDxPbvLZ9Gqs5darJAy/92Caq2V8IUwQEnlL9ONEKdcdzkLlgi MIME-Version: 1.0 X-Received: by 2002:a05:6638:d94:: with SMTP id l20mr195136jaj.134.1631146228485; Wed, 08 Sep 2021 17:10:28 -0700 (PDT) Date: Wed, 08 Sep 2021 17:10:28 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000868f9305cb84d318@google.com> Subject: [syzbot] possible deadlock in io_uring_register From: syzbot To: asml.silence@gmail.com, axboe@kernel.dk, io-uring@vger.kernel.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 Hello, syzbot found the following issue on: HEAD commit: ac08b1c68d1b Merge tag 'pci-v5.15-changes' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=177842dd300000 kernel config: https://syzkaller.appspot.com/x/.config?x=dc596ab8008badc2 dashboard link: https://syzkaller.appspot.com/bug?extid=97fa56483f69d677969f compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 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+97fa56483f69d677969f@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.14.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/25433 is trying to acquire lock: ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: io_register_iowq_max_workers fs/io_uring.c:10551 [inline] ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __io_uring_register fs/io_uring.c:10757 [inline] ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792 but task is already holding lock: ffff8880885b40a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x2e1/0x2e70 fs/io_uring.c:10791 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ctx->uring_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:596 [inline] __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729 __io_sq_thread fs/io_uring.c:7291 [inline] io_sq_thread+0x65a/0x1370 fs/io_uring.c:7368 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 (&sqd->lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __mutex_lock_common kernel/locking/mutex.c:596 [inline] __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729 io_register_iowq_max_workers fs/io_uring.c:10551 [inline] __io_uring_register fs/io_uring.c:10757 [inline] __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->uring_lock); lock(&sqd->lock); lock(&ctx->uring_lock); lock(&sqd->lock); *** DEADLOCK *** 1 lock held by syz-executor.5/25433: #0: ffff8880885b40a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x2e1/0x2e70 fs/io_uring.c:10791 stack backtrace: CPU: 1 PID: 25433 Comm: syz-executor.5 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __mutex_lock_common kernel/locking/mutex.c:596 [inline] __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729 io_register_iowq_max_workers fs/io_uring.c:10551 [inline] __io_uring_register fs/io_uring.c:10757 [inline] __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2de4e18188 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000020000140 RSI: 0000000000000013 RDI: 0000000000000005 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe0e2af47f R14: 00007f2de4e18300 R15: 0000000000022000 --- 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.