From: Tejun Heo <tj@kernel.org>
To: Douglas Miller <dougmill@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, Christoph Lameter <cl@linux.com>,
linux-block@vger.kernel.org,
Guilherme Piccoli <gpiccoli@br.ibm.com>
Subject: Re: [PATCH 1/1] percpu-refcount: fix reference leak during percpu-atomic transition
Date: Fri, 27 Jan 2017 17:09:58 -0500 [thread overview]
Message-ID: <20170127220958.GA2476@mtj.duckdns.org> (raw)
In-Reply-To: <1485550748-28075-1-git-send-email-dougmill@linux.vnet.ibm.com>
Hello, Douglas.
On Fri, Jan 27, 2017 at 02:59:08PM -0600, Douglas Miller wrote:
> @@ -212,7 +212,7 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
> this_cpu_inc(*percpu_count);
> ret = true;
> } else {
> - ret = atomic_long_inc_not_zero(&ref->count);
> + ret = (atomic_long_inc_not_zero(&ref->count) != 0);
> }
>
> rcu_read_unlock_sched();
> @@ -246,7 +246,7 @@ static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
> this_cpu_inc(*percpu_count);
> ret = true;
> } else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) {
> - ret = atomic_long_inc_not_zero(&ref->count);
> + ret = (atomic_long_inc_not_zero(&ref->count) != 0);
Ugh.... Damn it. This is why we use bools instead of ints for these
things. For some reason, we're returning bools but using an integer
variable to cache the result. :(
Can you please convert the local variable to bool instead?
Thanks a lot for spotting this.
--
tejun
next prev parent reply other threads:[~2017-01-27 22:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-27 20:59 Douglas Miller
2017-01-27 21:39 ` Douglas Miller
2017-01-27 22:09 ` Tejun Heo [this message]
2017-01-27 22:14 ` Jens Axboe
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