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 shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B062FC6FA82 for ; Thu, 22 Sep 2022 13:23:44 +0000 (UTC) Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.96) (envelope-from ) id 1obMB2-0004TX-11; Thu, 22 Sep 2022 09:23:40 -0400 Received: from mscreen.etri.re.kr ([129.254.9.16]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (Exim 4.96) (envelope-from ) id 1obMAz-0004Sj-2T for kernelnewbies@kernelnewbies.org; Thu, 22 Sep 2022 09:23:38 -0400 Received: from unknown (HELO send002-relay.gov-dooray.com) (211.180.235.153) by 129.254.9.16 with ESMTP; 22 Sep 2022 22:23:31 +0900 X-Original-SENDERIP: 211.180.235.153 X-Original-MAILFROM: ckim@etri.re.kr X-Original-RCPTTO: kernelnewbies@kernelnewbies.org Received: from [10.162.225.112] (HELO smtp002-imp.gov-dooray.com) ([10.162.225.112]) by send002-relay.gov-dooray.com with SMTP id 8226f4a2632c61d2; Thu, 22 Sep 2022 22:23:30 +0900 DKIM-Signature: a=rsa-sha256; b=lGhvX8EfyE1Z3rP8Ylv2zakyGdnV7of0HUsd5WLxqGqvT4JlgxpYIOqBFpaOK8ltp9QAgxVDGD wbNq1asyuJz6AI9B76LdqJI6YS4yP7fKvh3StkEdpoGUs7MQIzHAZq1fasJKepapo1pHOXDMqhhc duKQYjwJae0LgEV7k7dJBoAzGgO4ht3DntFpAhQT3qPKGxmh61Z0CGwPOyg/znTuDXyP1b9RM/pe 8kPPBz7i3pRaJWuWLg5M7ZmU1iDuxZOC8FgAbsMzfNijFgVx2fhfVDr99+rx49vV+r6R+YMsUqI+ udVFgT6QX6s3qkIeH9nu1+DNK85GVYTiuytJOFJQ==; c=relaxed/relaxed; s=selector; d=dooray.com; v=1; bh=i0AVkjLLIHMRP79q4w1R3gjhIybay7eTJoUQcmgp9CM=; h=From:To:Subject:Message-ID; Received: from [129.254.132.39] (HELO CHANKIMPC) ([129.254.132.39]) by smtp002-imp.gov-dooray.com with SMTP id 6b955f3c632c61d2; Thu, 22 Sep 2022 22:23:30 +0900 From: "Chan Kim" To: "'Greg KH'" References: <0ee901d8cda9$b1056ec0$13104c40$@etri.re.kr> In-Reply-To: Subject: RE: how to debug... program hangs while downing for write a rwsem Date: Thu, 22 Sep 2022 22:23:28 +0900 Message-ID: <002c01d8ce86$80c9fbd0$825df370$@etri.re.kr> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 16.0 Content-Language: ko Thread-Index: AQE9Q81cI79TXEdRUEP/7MQlsEV8owHTWFdzAd7ULSKvBPOiAA== Cc: kernelnewbies@kernelnewbies.org X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kernelnewbies-bounces@kernelnewbies.org And I am also trying to do the experiment with linux5.15.68. Somehow linux doesn't start with this new setup and I need some time. Thank you for the advices. Chan Kim >-----Original Message----- >From: Chan Kim >Sent: Thursday, September 22, 2022 10:18 PM >To: 'Greg KH' >Cc: 'kernelnewbies@kernelnewbies.org' >Subject: RE: how to debug... program hangs while downing for write a rwsem > >Hi, Greg K-H, > >I found the scheduler isn't working correct. >When I run an application instead of the shell, and when I call sleep() >inside the application, it hangs. >So I have to investigate about the clock settings first(in dts, etc). >(The serial port is 8250 compatible uart that we've been using). >Thank you. > >Chan Kim > >>-----Original Message----- >>From: Greg KH >>Sent: Wednesday, September 21, 2022 8:16 PM >>To: Chan Kim >>Cc: kernelnewbies@kernelnewbies.org >>Subject: Re: how to debug... program hangs while downing for write a >>rwsem >> >>On Wed, Sep 21, 2022 at 08:02:50PM +0900, Chan Kim wrote: >>> Hello kernel experts and users, >>> >>> I'm trying to boot linux-5.10.0-rc5 on our arm64 board (using >>> neoverse-v1 core). >> >>5.10-rc5 is very very very old and obsolete, and not even a real release. >>Why are you using that specific kernel version? >> >>At the very least, use a released and supported 5.10.y tree, but even >>better, use the latest 5.19.y release. >> >>> After the shell comes up, when I press enter key at the prompt, it >>> gives me another prompt. >>> But when I press enter key again, it stops responding. >>> After inspecting where the program hangs, I found it hangs in >>> function tty_set_termios while downing the rwsem. >>> Please see below where I marked "<===== this line "". (in file >>> drivers/tty/tty_ioctl.c) >>> >>> int tty_set_termios(struct tty_struct *tty, struct ktermios >>> *new_termios) { >>> struct ktermios old_termios; >>> struct tty_ldisc *ld; >>> >>> WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY && >>> tty->driver->subtype == PTY_TYPE_MASTER); >>> /* >>> * Perform the actual termios internal changes under lock. >>> */ >>> >>> >>> /* FIXME: we need to decide on some locking/ordering semantics >>> for the set_termios notification eventually */ >>> down_write(&tty->termios_rwsem); <====== this >>> line >> >>What serial driver are you using that is causing this problem? >> >>thanks, >> >>greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies