From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Daniel Wang <wonderfly@google.com>
Cc: sergey.senozhatsky.work@gmail.com, Petr Mladek <pmladek@suse.com>,
rostedt@goodmis.org, stable@vger.kernel.org,
Alexander.Levin@microsoft.com, akpm@linux-foundation.org,
byungchul.park@lge.com, dave.hansen@intel.com,
hannes@cmpxchg.org, jack@suse.cz, linux-kernel@vger.kernel.org,
linux-mm@kvack.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Mel Gorman <mgorman@suse.de>,
mhocko@kernel.org, pavel@ucw.cz,
penguin-kernel@i-love.sakura.ne.jp, peterz@infradead.org,
tj@kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz,
Cong Wang <xiyou.wangcong@gmail.com>,
Peter Feiner <pfeiner@google.com>
Subject: Re: 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes"
Date: Fri, 9 Nov 2018 15:47:40 +0900 [thread overview]
Message-ID: <20181109064740.GE599@jagdpanzerIV> (raw)
In-Reply-To: <CAJmjG2-c4e_1999n0OV5B9ABG9rF6n=myThjgX+Ms1R-vc3z+A@mail.gmail.com>
On (11/01/18 09:05), Daniel Wang wrote:
> > Another deadlock scenario could be the following one:
> >
> > printk()
> > console_trylock()
> > down_trylock()
> > raw_spin_lock_irqsave(&sem->lock, flags)
> > <NMI>
> > panic()
> > console_flush_on_panic()
> > console_trylock()
> > raw_spin_lock_irqsave(&sem->lock, flags) // deadlock
> >
> > There are no patches addressing this one at the moment. And it's
> > unclear if you are hitting this scenario.
>
> I am not sure, but Steven's patches did make the deadlock I saw go away...
You certainly can find cases when "busy spin on console_sem owner" logic
can reduce some possibilities.
But spin_lock(&lock); NMI; spin_lock(&lock); code is still in the kernel.
> A little swamped by other things lately but I'll run a test with it.
> If it works, would you recommend taking your patch alone
Let's first figure out if it works.
-ss
next prev parent reply other threads:[~2018-11-09 6:47 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 19:46 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes" Daniel Wang
2018-10-01 19:23 ` Steven Rostedt
2018-10-01 20:13 ` Pavel Machek
2018-10-01 20:21 ` Vlastimil Babka
2018-10-01 20:38 ` Daniel Wang
2018-10-01 20:29 ` Steven Rostedt
2018-10-01 20:37 ` Daniel Wang
2018-10-01 20:40 ` Sasha Levin
2018-10-02 8:42 ` Petr Mladek
2018-10-02 17:21 ` Daniel Wang
2018-10-03 0:15 ` Daniel Wang
2018-10-03 1:23 ` Steven Rostedt
2018-10-03 9:14 ` Petr Mladek
2018-10-03 17:16 ` Daniel Wang
2018-10-03 17:37 ` Steven Rostedt
2018-10-03 18:37 ` Daniel Wang
2018-10-03 23:37 ` Daniel Wang
2018-10-04 7:44 ` Sergey Senozhatsky
2018-10-04 8:05 ` Sergey Senozhatsky
2018-10-04 8:36 ` Petr Mladek
2018-10-04 8:55 ` Sergey Senozhatsky
2018-10-04 8:55 ` Sergey Senozhatsky
2018-10-21 18:09 ` Daniel Wang
2018-10-22 9:32 ` Petr Mladek
2018-10-22 10:09 ` Sergey Senozhatsky
2018-11-01 16:05 ` Daniel Wang
2018-11-09 6:47 ` Sergey Senozhatsky [this message]
2018-12-12 1:16 ` Daniel Wang
2018-12-12 5:21 ` Sergey Senozhatsky
2018-12-12 6:08 ` Daniel Wang
2018-12-12 6:28 ` Sergey Senozhatsky
2018-12-12 6:48 ` Sasha Levin
2018-12-12 8:10 ` Sergey Senozhatsky
2018-12-12 13:36 ` Petr Mladek
2018-12-12 13:59 ` Sergey Senozhatsky
2018-12-12 17:43 ` Sasha Levin
2018-12-12 20:11 ` Daniel Wang
2018-12-12 21:43 ` Sasha Levin
2018-12-12 21:49 ` Daniel Wang
2018-12-12 21:52 ` Sasha Levin
2018-12-12 21:56 ` Daniel Wang
2018-12-13 0:40 ` Daniel Wang
2018-12-13 2:27 ` Sergey Senozhatsky
2018-12-13 2:39 ` Daniel Wang
2018-12-13 9:59 ` Petr Mladek
2018-12-13 14:29 ` Sasha Levin
2018-12-13 2:07 ` Sergey Senozhatsky
2018-12-28 0:16 ` Sergey Senozhatsky
2018-12-28 8:27 ` Greg KH
2018-12-28 22:03 ` Daniel Wang
2018-12-30 3:03 ` Sergey Senozhatsky
2018-10-04 7:49 ` Petr Mladek
2018-10-02 8:16 ` 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=20181109064740.GE599@jagdpanzerIV \
--to=sergey.senozhatsky.work@gmail.com \
--cc=Alexander.Levin@microsoft.com \
--cc=akpm@linux-foundation.org \
--cc=byungchul.park@lge.com \
--cc=dave.hansen@intel.com \
--cc=hannes@cmpxchg.org \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mgorman@suse.de \
--cc=mhocko@kernel.org \
--cc=pavel@ucw.cz \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=peterz@infradead.org \
--cc=pfeiner@google.com \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--cc=stable@vger.kernel.org \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=vbabka@suse.cz \
--cc=wonderfly@google.com \
--cc=xiyou.wangcong@gmail.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.