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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 8D623C28CF6 for ; Fri, 27 Jul 2018 01:46:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2EACE206B7 for ; Fri, 27 Jul 2018 01:46:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sZ/XAtgx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2EACE206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732075AbeG0DFj (ORCPT ); Thu, 26 Jul 2018 23:05:39 -0400 Received: from mail-pl0-f65.google.com ([209.85.160.65]:44077 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731988AbeG0DFi (ORCPT ); Thu, 26 Jul 2018 23:05:38 -0400 Received: by mail-pl0-f65.google.com with SMTP id m16-v6so1598713pls.11; Thu, 26 Jul 2018 18:46:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=6OoCU4gvbuZ/lvBw3q96FLsiKMPPZwHaU/oVeaLz6mI=; b=sZ/XAtgxTOpEJah47Z76DiVgW4/udL5ej/SuvTjJuFLzTZMmMAhZIle/lXduAaib2t BreSv/RO064h3O+kJWP+4toGaINiWnjUNw8ujZk03Pj9LuUWgLLwIeBi/TM8AezUboAF eOaBpYXWzPmQRvzTi+n1dhi6e9rM1vMvGNa12cp+YTl6wshtH3SVVjm1bObPnCyQZF2X YrR0Ug5vf2+fVay+JaybJfi6eQu4UDGa0xZDO5QDQA3B09Whh1tZeSOLdKcIgXezN4s0 W51+OKVsaRe86KK7mjdkjNeBIE3DqKbqP9IDYiQBDKRw/a37dTyNanvUdTn5esY6g6S0 KqTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=6OoCU4gvbuZ/lvBw3q96FLsiKMPPZwHaU/oVeaLz6mI=; b=k8pXYt6dQnEGRqbdrrP1gUwIabHKJU2HjpDUCQ76QcZmGjwwYBNXYuQp4m5LBIGd+w +ZMyqr6KOTiQ7c1bycppKB8oIpjRLID7GEXIH6SLkNyfi8AGA8e9MC28MsI2nJg33Y0d yy8slYKi0yyjTVebIw/7CeuVXXStHnmoqMe4FE8M8zLbyKAJAJXAfkCUjuRcAHgDRTFe yAEi0QVojMTu6Ba1Ka4y4ADNo9lW86QmJbixcLMx8uVMED3Vjc0H85jnklh6SZdf4FOK ZDpl5gNepJQpk/MS2nG8z9yBsXAtkSG9MGm9epWHD+RtGN/mIaHZM2j1dyVRFewg9i+s lNqQ== X-Gm-Message-State: AOUpUlFawXPVcHy3ii0MXkDpmS190NoE4djJiwV1+JZp/x13T1cUiIQz 6cZJk/e3Nte44LK85xusSOY= X-Google-Smtp-Source: AAOMgpd9CQdJcx6sW84gI6otmUpB/3GhnPBB4/Np2gQL7sfiZY82n2vsyq8hIpROTsmXznjYXiKUYg== X-Received: by 2002:a17:902:8e86:: with SMTP id bg6-v6mr4077037plb.108.1532655971213; Thu, 26 Jul 2018 18:46:11 -0700 (PDT) Received: from dragonet (dragonet.kaist.ac.kr. [143.248.133.220]) by smtp.gmail.com with ESMTPSA id w70-v6sm3448327pgd.18.2018.07.26.18.46.09 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 26 Jul 2018 18:46:10 -0700 (PDT) Date: Fri, 27 Jul 2018 10:46:06 +0900 From: "Dae R. Jeong" To: jikos@kernel.org, axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, lifeasageek@gmail.com, kt0755@gmail.com Subject: WARNING: possible recursive locking detected Message-ID: <20180727014606.GA2786@dragonet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reporting the crash: WARNING: possible recursive locking detected This crash has been found in v4.18 using a modified version of Syzkaller, which focus on exploring hard-to-reach coverages. C repro code: https://kiwi.cs.purdue.edu/static/alexkkid-fuzzer/repro-8659a5.c Kernel config: https://kiwi.cs.purdue.edu/static/alexkkid-fuzzer/config-8659a5 Crash log: ============================================ WARNING: possible recursive locking detected 4.18.0-rc4 #1 Not tainted -------------------------------------------- kworker/u4:3/1039 is trying to acquire lock: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: start_flush_work kernel/workqueue.c:2888 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: flush_work+0x316/0x690 kernel/workqueue.c:2917 but task is already holding lock: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: process_one_work+0x857/0x1a30 kernel/workqueue.c:2124 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock((wq_completion)"floppy"); lock((wq_completion)"floppy"); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by kworker/u4:3/1039: #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000060a8cf4f ((wq_completion)"floppy"){+.+.}, at: process_one_work+0x857/0x1a30 kernel/workqueue.c:2124 #1: 000000002682ab21 (floppy_work){+.+.}, at: process_one_work+0x88e/0x1a30 kernel/workqueue.c:2128 stack backtrace: CPU: 0 PID: 1039 Comm: kworker/u4:3 Not tainted 4.18.0-rc4 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: floppy floppy_work_workfn Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x122/0x198 lib/dump_stack.c:113 print_deadlock_bug kernel/locking/lockdep.c:1765 [inline] check_deadlock kernel/locking/lockdep.c:1809 [inline] validate_chain kernel/locking/lockdep.c:2405 [inline] __lock_acquire+0xfd2/0x39f0 kernel/locking/lockdep.c:3435 lock_acquire+0x170/0x510 kernel/locking/lockdep.c:3924 start_flush_work kernel/workqueue.c:2889 [inline] flush_work+0x33b/0x690 kernel/workqueue.c:2917 __cancel_work_timer+0x298/0x3a0 kernel/workqueue.c:2989 cancel_work_sync+0x1c/0x20 kernel/workqueue.c:3025 cancel_activity drivers/block/floppy.c:1003 [inline] fd_watchdog+0xfe/0x160 drivers/block/floppy.c:1014 setup_rw_floppy+0x76a/0xa80 drivers/block/floppy.c:1512 seek_floppy drivers/block/floppy.c:1608 [inline] floppy_ready+0x4dd/0x18f0 drivers/block/floppy.c:1920 floppy_start+0x250/0x2d0 drivers/block/floppy.c:1936 floppy_work_workfn+0x1a/0x20 drivers/block/floppy.c:977 process_one_work+0x98d/0x1a30 kernel/workqueue.c:2153 worker_thread+0x8f/0xcf0 kernel/workqueue.c:2296 kthread+0x3d5/0x4b0 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412