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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 52274C33C9B for ; Tue, 7 Jan 2020 08:17:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 13807207E0 for ; Tue, 7 Jan 2020 08:17:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727689AbgAGIRM (ORCPT ); Tue, 7 Jan 2020 03:17:12 -0500 Received: from mail-io1-f69.google.com ([209.85.166.69]:42248 "EHLO mail-io1-f69.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726492AbgAGIRK (ORCPT ); Tue, 7 Jan 2020 03:17:10 -0500 Received: by mail-io1-f69.google.com with SMTP id e7so32727250iog.9 for ; Tue, 07 Jan 2020 00:17:10 -0800 (PST) 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=CF1DtUbvl3NqIQHwWCotHa59pd40wisr48XJ0Z4KZ7s=; b=NRIctQ6Y01crALQ6q/a2GOFMVKnjXXuancLX9pRmn09wy+IMa9NJuTYptBzObNi/wO Mys0mB+EJB+mhM7cDYpzBx5saoPhvaLEg0yO4VzUC1BLr2rn04JdxQdpmRhtXG/fkYTR ohxJht2m3x31TErhmj74fn3gSD2zSYzGAyigRWRURzSNj0iG1R8HaXX/NugXmwtFRBOU FWkREpNfDxf/wBg3lFahsawctFsuuRRsSbVTxfkzAy9DUHtOQW/L7zxPn+WeiNzuCmOu WOmtRx45mQG7WX9wjrjVSh/Iw2LgdDR5xZMx6dGhLk+RZ+tzp5nHplaHK0OuqBOiVLS1 kVIA== X-Gm-Message-State: APjAAAW3hdS4NrDH43bdm5LVBxKvWlG9U98o9SoZMtrtvnytvlK6Z8pX s/qt2ISsitZcnxipebhaeYhaF0EDsLDRbl2Ef+4CHKVNZ0TO X-Google-Smtp-Source: APXvYqywoUBzH+xwG38s/p9kdXwe9hW14P6V3xEZhhojFC3BPUjV6R/Ulaj3SHgTjwqBa2/cPhr/XioPs7dwpEPC6Kh0+FfZYNkP MIME-Version: 1.0 X-Received: by 2002:a02:8587:: with SMTP id d7mr82407375jai.39.1578385029689; Tue, 07 Jan 2020 00:17:09 -0800 (PST) Date: Tue, 07 Jan 2020 00:17:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000037cd5059b8867f8@google.com> Subject: INFO: task hung in con_install From: syzbot To: daniel.vetter@ffwll.ch, ghalat@redhat.com, gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org, nico@fluxnic.net, sam@ravnborg.org, syzkaller-bugs@googlegroups.com, textshell@uchuujin.de Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: fd698849 Linux 5.5-rc4 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1170c085e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=874bac2ff63646fa dashboard link: https://syzkaller.appspot.com/bug?extid=370b0e19c5405cfd7173 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+370b0e19c5405cfd7173@syzkaller.appspotmail.com INFO: task syz-executor.4:30304 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28552 30304 9223 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x176/0x2c0 kernel/locking/semaphore.c:237 down+0x64/0x90 kernel/locking/semaphore.c:61 console_lock+0x29/0x80 kernel/printk/printk.c:2289 con_install+0x4a/0x410 drivers/tty/vt/vt.c:3228 tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline] tty_init_dev drivers/tty/tty_io.c:1341 [inline] tty_init_dev+0xf9/0x470 drivers/tty/tty_io.c:1318 tty_open_by_driver drivers/tty/tty_io.c:1987 [inline] tty_open+0x4a5/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007fd6e11307a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007fd6e11307d0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007fd6e11316d4 R13: 00000000004cb17d R14: 00000000004e4888 R15: 00000000ffffffff INFO: task syz-executor.1:30305 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28552 30305 9214 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007fd548a717a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007fd548a717d0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007fd548a726d4 R13: 00000000004cb17d R14: 00000000004e4888 R15: 00000000ffffffff INFO: task syz-executor.3:30397 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28552 30397 9220 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007efd38a3e7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007efd38a3e7d0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007efd38a3f6d4 R13: 00000000004cb17d R14: 00000000004e4888 R15: 00000000ffffffff INFO: task syz-executor.3:30508 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28304 30508 9220 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007efd38a1d7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007efd38a1d7d0 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007efd38a1e6d4 R13: 00000000004cb17d R14: 00000000004e4888 R15: 00000000ffffffff INFO: task syz-executor.5:30847 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28552 30847 7317 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007f2455ce37a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007f2455ce37d0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007f2455ce46d4 R13: 00000000004cb067 R14: 00000000004e4738 R15: 00000000ffffffff INFO: task syz-executor.5:30861 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28240 30861 7317 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146b1 Code: 18 48 8d 6c 24 18 48 8d 05 3c 2b 04 00 48 89 44 24 08 48 8b 44 24 28 48 89 44 24 10 48 8d 44 24 08 48 89 04 24 e8 4f 57 04 00 <48> 8b 6c 24 18 48 83 c4 20 c3 e8 90 58 04 00 eb ae cc cc cc cc cc RSP: 002b:00007f2455cc27a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004146b1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007f2455cc27d0 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007f2455cc36d4 R13: 00000000004cb067 R14: 00000000004e4738 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1112: #0: ffffffff899a5680 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9080: #0: ffff888098d8ab20 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9171: #0: ffff888093c28090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000175b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9172: #0: ffff8880a8e31090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000173b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9173: #0: ffff88809655b090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000176b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9174: #0: ffff8880a2d99090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9175: #0: ffff8880a2ff4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000174b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9176: #0: ffff8882156f2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900011202e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/7654: #0: ffff88805c8ef090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900078932e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.4/30304: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 #1: ffff88809fb0d198 (&tty->legacy_mutex){+.+.}, at: tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/30294: 1 lock held by syz-executor.1/30305: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.3/30397: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.3/30508: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.5/30847: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.5/30861: #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eceb20 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1112 Comm: khungtaskd Not tainted 5.5.0-rc4-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 30294 Comm: syz-executor.2 Not tainted 5.5.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180 Code: cc cc cc cc cc cc cc cc cc 65 48 8b 04 25 c0 1e 02 00 48 8b 80 98 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 84 f0 8c 7e 81 e2 00 RSP: 0018:ffffc900071375c0 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff83b4fb70 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffffc90007137610 R08: ffff88805bfc80c0 R09: 0000000000000040 R10: fffffbfff14f33af R11: ffffffff8a799d7b R12: 0000000000001400 R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000 FS: 00007f8228648700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8bedbd8000 CR3: 00000000a28f9000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_do_set_font+0x81f/0x960 drivers/video/fbdev/core/fbcon.c:2604 fbcon_set_font+0x72e/0x860 drivers/video/fbdev/core/fbcon.c:2696 con_font_set drivers/tty/vt/vt.c:4538 [inline] con_font_op+0xe30/0x1270 drivers/tty/vt/vt.c:4603 vt_ioctl+0xd2e/0x26d0 drivers/tty/vt/vt_ioctl.c:913 tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a919 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8228647c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a919 RDX: 0000000020000100 RSI: 0000000000004b61 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82286486d4 R13: 00000000004c5c8b R14: 00000000004dc080 R15: 00000000ffffffff --- This bug 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 bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.