Linux-mm Archive on lore.kernel.org
 help / color / Atom feed
From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Qian Cai <cai@lca.pw>
Cc: arnd@arndb.de, gregkh@linuxfoundation.org,
	sergey.senozhatsky.work@gmail.com, pmladek@suse.com,
	rostedt@goodmis.org, catalin.marinas@arm.com, will@kernel.org,
	dan.j.williams@intel.com, peterz@infradead.org,
	longman@redhat.com, tglx@linutronix.de, linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] char/random: silence a lockdep splat with printk()
Date: Tue, 7 Jan 2020 16:07:24 -0500
Message-ID: <20200107210724.GN3619@mit.edu> (raw)
In-Reply-To: <1573679785-21068-1-git-send-email-cai@lca.pw>

On Wed, Nov 13, 2019 at 04:16:25PM -0500, Qian Cai wrote:
> From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
> 
> Sergey didn't like the locking order,
> 
> uart_port->lock  ->  tty_port->lock
> 
> uart_write (uart_port->lock)
>   __uart_start
>     pl011_start_tx
>       pl011_tx_chars
>         uart_write_wakeup
>           tty_port_tty_wakeup
>             tty_port_default
>               tty_port_tty_get (tty_port->lock)
> 
> but those code is so old, and I have no clue how to de-couple it after
> checking other locks in the splat. There is an onging effort to make all
> printk() as deferred, so until that happens, workaround it for now as a
> short-term fix.

Applied, thanks.

					- Ted


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-13 21:16 Qian Cai
2019-12-03 18:46 ` Qian Cai
2019-12-05  1:00   ` Sergey Senozhatsky
2019-12-17  1:52     ` Qian Cai
2020-01-02 15:42       ` Qian Cai
2020-01-02 17:07         ` Steven Rostedt
2020-01-02 17:16           ` Qian Cai
2020-01-02 18:00         ` Theodore Y. Ts'o
2020-01-07 21:07 ` Theodore Y. Ts'o [this message]
2020-03-24 15:13 ` dmesg -w regression in v5.4.22, bisected, was: " Zygo Blaxell
2020-03-25  2:35   ` Sergey Senozhatsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200107210724.GN3619@mit.edu \
    --to=tytso@mit.edu \
    --cc=arnd@arndb.de \
    --cc=cai@lca.pw \
    --cc=catalin.marinas@arm.com \
    --cc=dan.j.williams@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=longman@redhat.com \
    --cc=peterz@infradead.org \
    --cc=pmladek@suse.com \
    --cc=rostedt@goodmis.org \
    --cc=sergey.senozhatsky.work@gmail.com \
    --cc=tglx@linutronix.de \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org
	public-inbox-index linux-mm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git