From: Zheng Yejian <zhengyejian1@huawei.com>
To: <gregkh@linuxfoundation.org>, <lee.jones@linaro.org>,
<stable@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <tglx@linutronix.de>, <cj.chengjian@huawei.com>,
<judy.chenhui@huawei.com>, <zhangjinhao2@huawei.com>,
<nixiaoming@huawei.com>
Subject: [PATCH 4.4 0/3] Backport patch series to update Futex from 4.9
Date: Tue, 9 Mar 2021 11:06:02 +0800 [thread overview]
Message-ID: <20210309030605.3295183-1-zhengyejian1@huawei.com> (raw)
Lee sent a patchset to update Futex for 4.9, see https://www.spinics.net/lists/stable/msg443081.html,
Then Xiaoming sent a follow-up patch for it, see https://lore.kernel.org/lkml/20210225093120.GD641347@dell/.
These patchsets may also resolve following issues in 4.4.260 which have been reported in 4.9,
see https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/?h=linux-4.4.y&id=319f66f08de1083c1fe271261665c209009dd65a
> /*
> * The task is on the way out. When the futex state is
> * FUTEX_STATE_DEAD, we know that the task has finished
> * the cleanup:
> */
> int ret = (p->futex_state = FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN;
Here may be:
int ret = (p->futex_state == FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN;
> raw_spin_unlock_irq(&p->pi_lock);
> /*
> * If the owner task is between FUTEX_STATE_EXITING and
> * FUTEX_STATE_DEAD then store the task pointer and keep
> * the reference on the task struct. The calling code will
> * drop all locks, wait for the task to reach
> * FUTEX_STATE_DEAD and then drop the refcount. This is
> * required to prevent a live lock when the current task
> * preempted the exiting task between the two states.
> */
> if (ret == -EBUSY)
And here, the variable "ret" may only be "-ESRCH" or "-EAGAIN", but not "-EBUSY".
> *exiting = p;
> else
> put_task_struct(p);
Since 074e7d515783 ("futex: Ensure the correct return value from futex_lock_pi()") has
been merged in 4.4.260, I send the remain 3 patches.
Peter Zijlstra (1):
futex: Change locking rules
Thomas Gleixner (2):
futex: Cure exit race
futex: fix dead code in attach_to_pi_owner()
kernel/futex.c | 209 +++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 177 insertions(+), 32 deletions(-)
--
2.25.4
next reply other threads:[~2021-03-09 3:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 3:06 Zheng Yejian [this message]
2021-03-09 3:06 ` [PATCH 4.4 1/3] futex: Change locking rules Zheng Yejian
2021-03-09 10:40 ` Greg KH
2021-03-09 3:06 ` [PATCH 4.4 2/3] futex: Cure exit race Zheng Yejian
2021-03-09 3:06 ` [PATCH 4.4 3/3] futex: fix dead code in attach_to_pi_owner() Zheng Yejian
2021-03-09 10:40 ` Greg KH
2021-03-09 18:14 ` Lee Jones
2021-03-10 12:00 ` Greg KH
2021-03-10 13:28 ` Lee Jones
2021-03-10 14:10 ` Greg KH
2021-03-11 1:39 ` Zhengyejian (Zetta)
2021-03-09 10:41 ` [PATCH 4.4 0/3] Backport patch series to update Futex from 4.9 Greg KH
2021-03-11 3:48 ` Zhengyejian (Zetta)
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