From: Lee Jones <lee.jones@linaro.org>
To: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
sashal@kernel.org, tglx@linutronix.de, wangle6@huawei.com,
zhengyejian1@huawei.com
Subject: Re: [PATCH] futex: fix dead code in attach_to_pi_owner()
Date: Thu, 25 Feb 2021 09:31:20 +0000 [thread overview]
Message-ID: <20210225093120.GD641347@dell> (raw)
In-Reply-To: <71a24b9b-2a65-57a1-55bb-95f7ec3287dd@huawei.com>
On Thu, 25 Feb 2021, Xiaoming Ni wrote:
> On 2021/2/25 16:25, Greg KH wrote:
> > On Mon, Feb 22, 2021 at 08:53:52PM +0800, Xiaoming Ni wrote:
> > > From: Thomas Gleixner <tglx@linutronix.de>
> > >
> > > The handle_exit_race() function is defined in commit c158b461306df82
> > > ("futex: Cure exit race"), which never returns -EBUSY. This results
> > > in a small piece of dead code in the attach_to_pi_owner() function:
> > >
> > > int ret = handle_exit_race(uaddr, uval, p); /* Never return -EBUSY */
> > > ...
> > > if (ret == -EBUSY)
> > > *exiting = p; /* dead code */
> > >
> > > The return value -EBUSY is added to handle_exit_race() in upsteam
> > > commit ac31c7ff8624409 ("futex: Provide distinct return value when
> > > owner is exiting"). This commit was incorporated into v4.9.255, before
> > > the function handle_exit_race() was introduced, whitout Modify
> > > handle_exit_race().
> > >
> > > To fix dead code, extract the change of handle_exit_race() from
> > > commit ac31c7ff8624409 ("futex: Provide distinct return value when owner
> > > is exiting"), re-incorporated.
> mainline:
> ac31c7ff8624 futex: Provide distinct return value when owner is exiting
>
> > >
> > > Fixes: c158b461306df82 ("futex: Cure exit race")
>
> stable linux-4.9.y
> 9c3f39860367 futex: Cure exit race
> c27f392040e2 futex: Provide distinct return value when owner is exiting
>
> > > Cc: stable@vger.kernel.org # 4.9.258-rc1
> > > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > > ---
> > > kernel/futex.c | 6 +++---
> > > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > What is the git commit id of this patch in Linus's tree?
> >
> > Also, what kernel tree(s) is this supposed to go to?
> >
> > thanks,
> >
> > greg k-h
> > .
> >
> Sorry, the commit id c158b461306df82 in the patch does not exist in the
> linux-stable repository.
> The commit ID is from linux-stable-rc.
>
> I corrected the commit id in a subsequent email, and added a branch label.
> https://lore.kernel.org/lkml/20210224100923.51315-1-nixiaoming@huawei.com/
Replied to the follow-up.
> Sorry, I forgot to use "--in-reply-to=" when I sent the update patch.
>
> This issue occurs only in the linux-4.9.y branch v4.9.258
--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
prev parent reply other threads:[~2021-02-25 9:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 12:53 [PATCH] futex: fix dead code in attach_to_pi_owner() Xiaoming Ni
2021-02-25 8:25 ` Greg KH
2021-02-25 8:56 ` Xiaoming Ni
2021-02-25 9:31 ` Lee Jones [this message]
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