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 263BEC4332F for ; Mon, 14 Nov 2022 14:55:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236650AbiKNOzy (ORCPT ); Mon, 14 Nov 2022 09:55:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235920AbiKNOzx (ORCPT ); Mon, 14 Nov 2022 09:55:53 -0500 Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C47C19035 for ; Mon, 14 Nov 2022 06:55:52 -0800 (PST) Received: by mail-io1-f69.google.com with SMTP id f25-20020a5d8799000000b006a44e33ddb6so5863156ion.1 for ; Mon, 14 Nov 2022 06:55:52 -0800 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y25-20020a5d9b19000000b006c1dfd6abd9mr5649948ion.0.1668437751998; Mon, 14 Nov 2022 06:55:51 -0800 (PST) Date: Mon, 14 Nov 2022 06:55:51 -0800 In-Reply-To: <000000000000cceef005ed659943@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000089b1a405ed6f6ff7@google.com> Subject: Re: [syzbot] possible deadlock in virtual_nci_close From: syzbot To: bongsu.jeon@samsung.com, dvyukov@google.com, krzysztof.kozlowski@linaro.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot has found a reproducer for the following issue on: HEAD commit: 1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=108bcd85880000 kernel config: https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: arm64 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11b08dd1880000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14fcee02880000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com nci: nci_start_poll: failed to set local general bytes nci: __nci_request: wait_for_completion_interruptible_timeout failed 0 ====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0 Not tainted ------------------------------------------------------ syz-executor424/3032 is trying to acquire lock: ffff80000d5fac10 (nci_mutex){+.+.}-{3:3}, at: virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44 but task is already holding lock: ffff0000cb900350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x74/0x2b4 net/nfc/nci/core.c:560 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ndev->req_lock){+.+.}-{3:3}: __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 nci_request net/nfc/nci/core.c:148 [inline] nci_set_local_general_bytes+0xbc/0x480 net/nfc/nci/core.c:774 nci_start_poll+0x1e8/0x474 net/nfc/nci/core.c:838 nfc_start_poll+0xfc/0x170 net/nfc/core.c:225 nfc_genl_start_poll+0xd4/0x174 net/nfc/netlink.c:828 genl_family_rcv_msg_doit net/netlink/genetlink.c:756 [inline] genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x458/0x4f4 net/netlink/genetlink.c:850 netlink_rcv_skb+0xe8/0x1d4 net/netlink/af_netlink.c:2540 genl_rcv+0x38/0x50 net/netlink/genetlink.c:861 netlink_unicast_kernel+0xfc/0x1dc net/netlink/af_netlink.c:1319 netlink_unicast+0x164/0x248 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x484/0x584 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0x2f8/0x440 net/socket.c:2482 ___sys_sendmsg net/socket.c:2536 [inline] __sys_sendmsg+0x1ac/0x228 net/socket.c:2565 __do_sys_sendmsg net/socket.c:2574 [inline] __se_sys_sendmsg net/socket.c:2572 [inline] __arm64_sys_sendmsg+0x2c/0x3c net/socket.c:2572 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #2 (&genl_data->genl_data_mutex){+.+.}-{3:3}: __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 nfc_urelease_event_work+0x88/0x16c net/nfc/netlink.c:1811 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863 -> #1 (nfc_devlist_mutex){+.+.}-{3:3}: __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 nfc_register_device+0x34/0x208 net/nfc/core.c:1116 nci_register_device+0x338/0x3b0 net/nfc/nci/core.c:1256 virtual_ncidev_open+0x6c/0xd8 drivers/nfc/virtual_ncidev.c:146 misc_open+0x1b8/0x200 drivers/char/misc.c:143 chrdev_open+0x2b4/0x2e8 fs/char_dev.c:414 do_dentry_open+0x364/0x748 fs/open.c:882 vfs_open+0x38/0x48 fs/open.c:1013 do_open fs/namei.c:3557 [inline] path_openat+0xe34/0x11c4 fs/namei.c:3713 do_filp_open+0xdc/0x1b8 fs/namei.c:3740 do_sys_openat2+0xb8/0x22c fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_openat fs/open.c:1342 [inline] __se_sys_openat fs/open.c:1337 [inline] __arm64_sys_openat+0xb0/0xe0 fs/open.c:1337 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 -> #0 (nci_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44 nci_close_device+0x188/0x2b4 net/nfc/nci/core.c:592 nci_unregister_device+0x3c/0x100 net/nfc/nci/core.c:1291 virtual_ncidev_close+0x70/0xb0 drivers/nfc/virtual_ncidev.c:166 __fput+0x198/0x3e4 fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x100/0x148 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x2dc/0xcac kernel/exit.c:820 do_group_exit+0x98/0xcc kernel/exit.c:950 get_signal+0xabc/0xb2c kernel/signal.c:2858 do_signal+0x128/0x438 arch/arm64/kernel/signal.c:1071 do_notify_resume+0xc0/0x1f0 arch/arm64/kernel/signal.c:1124 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x9c/0x150 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 other info that might help us debug this: Chain exists of: nci_mutex --> &genl_data->genl_data_mutex --> &ndev->req_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ndev->req_lock); lock(&genl_data->genl_data_mutex); lock(&ndev->req_lock); lock(nci_mutex); *** DEADLOCK *** 1 lock held by syz-executor424/3032: #0: ffff0000cb900350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x74/0x2b4 net/nfc/nci/core.c:560 stack backtrace: CPU: 0 PID: 3032 Comm: syz-executor424 Not tainted 6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156 show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2055 check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44 nci_close_device+0x188/0x2b4 net/nfc/nci/core.c:592 nci_unregister_device+0x3c/0x100 net/nfc/nci/core.c:1291 virtual_ncidev_close+0x70/0xb0 drivers/nfc/virtual_ncidev.c:166 __fput+0x198/0x3e4 fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x100/0x148 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x2dc/0xcac kernel/exit.c:820 do_group_exit+0x98/0xcc kernel/exit.c:950 get_signal+0xabc/0xb2c kernel/signal.c:2858 do_signal+0x128/0x438 arch/arm64/kernel/signal.c:1071 do_notify_resume+0xc0/0x1f0 arch/arm64/kernel/signal.c:1124 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x9c/0x150 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584