From: Zhen Lei <thunder.leizhen@huawei.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable <stable@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
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: [PATCH 4.4 02/11] futex: Cleanup refcounting
Date: Mon, 2 Aug 2021 21:46:15 +0800 [thread overview]
Message-ID: <20210802134624.1934-3-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20210802134624.1934-1-thunder.leizhen@huawei.com>
From: Peter Zijlstra <peterz@infradead.org>
[ Upstream commit bf92cf3a5100f5a0d5f9834787b130159397cb22 ]
Add a put_pit_state() as counterpart for get_pi_state() so the refcounting
becomes consistent.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170322104151.801778516@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
kernel/futex.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index dbb38e14f6fcc8e..dab9c79a931a23e 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -825,7 +825,7 @@ static int refill_pi_state_cache(void)
return 0;
}
-static struct futex_pi_state * alloc_pi_state(void)
+static struct futex_pi_state *alloc_pi_state(void)
{
struct futex_pi_state *pi_state = current->pi_state_cache;
@@ -858,6 +858,11 @@ static void pi_state_update_owner(struct futex_pi_state *pi_state,
}
}
+static void get_pi_state(struct futex_pi_state *pi_state)
+{
+ WARN_ON_ONCE(!atomic_inc_not_zero(&pi_state->refcount));
+}
+
/*
* Drops a reference to the pi_state object and frees or caches it
* when the last reference is gone.
@@ -901,7 +906,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
* Look up the task based on what TID userspace gave us.
* We dont trust it.
*/
-static struct task_struct * futex_find_get_task(pid_t pid)
+static struct task_struct *futex_find_get_task(pid_t pid)
{
struct task_struct *p;
@@ -1149,7 +1154,7 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
goto out_einval;
out_attach:
- atomic_inc(&pi_state->refcount);
+ get_pi_state(pi_state);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
*ps = pi_state;
return 0;
@@ -2204,7 +2209,7 @@ retry_private:
*/
if (requeue_pi) {
/* Prepare the waiter to take the rt_mutex. */
- atomic_inc(&pi_state->refcount);
+ get_pi_state(pi_state);
this->pi_state = pi_state;
ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex,
this->rt_waiter,
--
2.26.0.106.g9fadedd
next prev parent reply other threads:[~2021-08-02 13:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-02 13:46 [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios 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 ` Zhen Lei [this message]
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 ` [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios Joe Korty
2021-08-08 6:46 ` Greg Kroah-Hartman
2021-08-08 7:22 [PATCH 4.4 00/11] 4.4.280-rc1 review Greg Kroah-Hartman
2021-08-08 7:22 ` [PATCH 4.4 02/11] futex: Cleanup refcounting 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=20210802134624.1934-3-thunder.leizhen@huawei.com \
--to=thunder.leizhen@huawei.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 \
/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 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).