LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Joe Korty <joe.korty@concurrent-rt.com>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable <stable@vger.kernel.org>,
	Anna-Maria Gleixner <anna-maria@linutronix.de>,
	Mike Galbraith <efault@gmx.de>,
	Sasha Levin <sasha.levin@oracle.com>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios
Date: Mon, 2 Aug 2021 20:53:25 -0400	[thread overview]
Message-ID: <20210803005325.GA32484@zipoli.concurrent-rt.com> (raw)
In-Reply-To: <20210802134624.1934-1-thunder.leizhen@huawei.com>

On Mon, Aug 02, 2021 at 09:46:13PM +0800, Zhen Lei wrote:
> Commit 73d786bd043e "futex: Rework inconsistent rt_mutex/futex_q state"
> mentions that it could cause an infinite loop, and will fix it in the later
> patches:
> bebe5b514345f09 futex: Futex_unlock_pi() determinism
> cfafcd117da0216 futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()
> 
> But at the moment they're not backported. In a single-core environment, the
> probability of triggering is high.
> 
> I also backported commit b4abf91047cf ("rtmutex: Make wait_lock irq safe"),
> it fixes a potential deadlock problem. Although it hasn't actually been
> triggered in our environment at the moment.
> 
> Other patches are used to resolve conflicts or fix problems caused by new
> patches.
> 
> 
> Anna-Maria Gleixner (1):
>   rcu: Update documentation of rcu_read_unlock()
> 
> Mike Galbraith (1):
>   futex: Handle transient "ownerless" rtmutex state correctly
> 
> Peter Zijlstra (6):
>   futex: Cleanup refcounting
>   futex,rt_mutex: Introduce rt_mutex_init_waiter()
>   futex: Pull rt_mutex_futex_unlock() out from under hb->lock
>   futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()
>   futex: Futex_unlock_pi() determinism
>   futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock()
> 
> Thomas Gleixner (3):
>   futex: Rename free_pi_state() to put_pi_state()
>   rtmutex: Make wait_lock irq safe
>   futex: Avoid freeing an active timer
> 
>  include/linux/rcupdate.h        |   4 +-
>  kernel/futex.c                  | 245 +++++++++++++++++++++-----------
>  kernel/locking/rtmutex.c        | 185 +++++++++++++-----------
>  kernel/locking/rtmutex_common.h |   2 +-
>  4 files changed, 262 insertions(+), 174 deletions(-)


To all concerned,

I have verified that this series of patches, when applied
to 4.4.277, passes the futex-unlock-pi replicator I posted
to lkml on July 19.

  Subject: [BUG] 4.4.262: infinite loop in futex_unlock_pi (EAGAIN loop)

Acked-by: Joe Korty <joe.korty@concurrent-rt.com>


  parent reply	other threads:[~2021-08-03  0:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:46 Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 01/11] futex: Rename free_pi_state() to put_pi_state() Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 02/11] futex: Cleanup refcounting Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 03/11] futex,rt_mutex: Introduce rt_mutex_init_waiter() Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 04/11] futex: Pull rt_mutex_futex_unlock() out from under hb->lock Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 05/11] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 06/11] futex: Futex_unlock_pi() determinism Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 07/11] rtmutex: Make wait_lock irq safe Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 08/11] futex: Handle transient "ownerless" rtmutex state correctly Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 09/11] futex: Avoid freeing an active timer Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 10/11] futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock() Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock() Zhen Lei
2021-08-03  0:53 ` Joe Korty [this message]
2021-08-08  6:46   ` [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios Greg Kroah-Hartman

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=20210803005325.GA32484@zipoli.concurrent-rt.com \
    --to=joe.korty@concurrent-rt.com \
    --cc=anna-maria@linutronix.de \
    --cc=efault@gmx.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=sasha.levin@oracle.com \
    --cc=stable@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=thunder.leizhen@huawei.com \
    --subject='Re: [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).