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Fri, 4 Oct 2019 09:12:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:38814 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387545AbfJDNMw (ORCPT ); Fri, 4 Oct 2019 09:12:52 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EC365215EA; Fri, 4 Oct 2019 13:12:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570194771; bh=SSmPcvLZmSMyjaaVpSqokklrhqv+4ipEMepV2hCCcu4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=b8P+Cgkqc1I7N7eQ5K66gNOHRmyaAolFQnRY0sxQxc+m8RwIelPJhFJKiUh0Ncn/R axdNMg2qsmGIJr3tR9OmyzpyG7rXsDeE1BfZ3noCLmrALhr5WbkDGc2jPZhF4iYEju pIPdr41eBy0Wev9SpS9OljuAsvpDY4Fu1cuZVKsA= Date: Fri, 4 Oct 2019 15:12:48 +0200 From: Greg KH To: Qiujun Huang Cc: jslaby@suse.com, nico@fluxnic.net, textshell@uchuujin.de, daniel.vetter@ffwll.ch, sam@ravnborg.org, mpatocka@redhat.com, ghalat@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tty/vt: Touch NMI watchdog in vt_console_print Message-ID: <20191004131248.GA644694@kroah.com> References: <1568969846-1800-1-git-send-email-hqjagain@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1568969846-1800-1-git-send-email-hqjagain@gmail.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 20, 2019 at 04:57:26PM +0800, Qiujun Huang wrote: > vt_console_print could trigger NMI watchdog in case writing slow: > > [2858736.789664] NMI watchdog: Watchdog detected hard LOCKUP on cpu 23 > ... > [2858736.790194] CPU: 23 PID: 32504 Comm: tensorflow_mode Not tainted 4.4.131-1.el7.elrepo.x86_64 #1 > [2858736.790206] Hardware name: Huawei RH2288 V3/BC11HGSB0, BIOS 3.57 02/26/2017 > [2858736.790222] task: ffff881e0a191640 ti: ffff881fd73a8000 task.ti: ffff881fd73a8000 > [2858736.790358] RIP: 0010:[] [] native_queued_spin_lock_slowpath+0x15e/0x170 > [2858736.790363] RSP: 0018:ffff88203f043db0 EFLAGS: 00000002 > [2858736.790365] RAX: 00000000005c0101 RBX: 0000000000000246 RCX: 0000000000000001 > ... > [2858736.790452] Call Trace: > [2858736.790521] > [2858736.790521] [] queued_spin_lock_slowpath+0xb/0xf > [2858736.790552] [] _raw_spin_lock_irqsave+0x37/0x40 > [2858736.790653] [] scsi_end_request+0x104/0x1d0 > [2858736.790656] [] scsi_io_completion+0x153/0x650 > [2858736.790671] [] scsi_finish_command+0xd2/0x120 > [2858736.790673] [] scsi_softirq_done+0x127/0x150 > [2858736.790749] [] blk_done_softirq+0x8e/0xc0 > [2858736.790811] [] __do_softirq+0xeb/0x2f0 > [2858736.790813] [] irq_exit+0xf5/0x100 > [2858736.790867] [] smp_call_function_single_interrupt+0x39/0x40 > [2858736.790890] [] call_function_single_interrupt+0x9b/0xa0 > [2858736.790973] > ... > > PID: 1793 TASK: ffff88103445c2c0 CPU: 32 COMMAND: "java" > #0 [ffff88103fe88e38] crash_nmi_callback at ffffffff810504d7 > #1 [ffff88103fe88e48] nmi_handle at ffffffff8101c1f7 > #2 [ffff88103fe88ea0] default_do_nmi at ffffffff8101c7d0 > #3 [ffff88103fe88ec0] do_nmi at ffffffff8101c901 > #4 [ffff88103fe88ee8] end_repeat_nmi at ffffffff8171176a > [exception RIP: cfb_imageblit+1167] > RIP: ffffffff813bdf8f RSP: ffff880006823380 RFLAGS: 00000046 > RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000005 > RDX: 000000000000024d RSI: 00000000ff000000 RDI: 0000000000000001 > RBP: ffff8800068233f0 R8: ffffffff81785e80 R9: ffffc9000c843168 > R10: 0000000000000001 R11: 0000000000000000 R12: ffff882037a831ba > R13: ffff882037a831af R14: ffffc9000c84316c R15: ffffc9000c843000 > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > --- --- > #5 [ffff880006823380] cfb_imageblit at ffffffff813bdf8f > #6 [ffff880006823398] bit_putcs at ffffffff813b2307 > #7 [ffff8800068234d0] bit_cursor at ffffffff813b1fc8 > #8 [ffff8800068235f0] fbcon_scroll at ffffffff813aebda > #9 [ffff880006823650] scrup at ffffffff81442600 > ... > > the cpu23 wait for the same blk queue_lock Why is this acting "slow"? Do we want to sprinkle this type of call everywhere in the console layer (hint, I doubt it.) This feels like something odd is wrong with your system, not with the tty layer... thanks, greg k-h