From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
peterz@infradead.org, torvalds@linux-foundation.org,
konrad.wilk@oracle.com, pbonzini@redhat.com,
paulmck@linux.vnet.ibm.com, waiman.long@hp.com, davej@redhat.com,
x86@kernel.org, jeremy@goop.org, paul.gortmaker@windriver.com,
ak@linux.intel.com, jasowang@redhat.com,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
xen-devel@lists.xenproject.org, riel@redhat.com,
borntraeger@de.ibm.com, akpm@linux-foundation.org,
a.ryabinin@samsung.com, sasha.levin@oracle.com,
dave@stgolabs.net
Subject: Re: [PATCH V3] x86 spinlock: Fix memory corruption on completing completions
Date: Thu, 12 Feb 2015 19:51:55 +0530 [thread overview]
Message-ID: <54DCB703.9020109@linux.vnet.ibm.com> (raw)
In-Reply-To: <20150212133707.GA10232@redhat.com>
On 02/12/2015 07:07 PM, Oleg Nesterov wrote:
> On 02/12, Raghavendra K T wrote:
>>
>> @@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
>> * check again make sure it didn't become free while
>> * we weren't looking.
>> */
>> - if (ACCESS_ONCE(lock->tickets.head) == want) {
>> + head = ACCESS_ONCE(lock->tickets.head);
>> + if (__tickets_equal(head, want)) {
>> add_stats(TAKEN_SLOW_PICKUP, 1);
>
> While at it, perhaps it makes sense to s/ACCESS_ONCE/READ_ONCE/ but this
> is cosmetic.
yes.. will do.
>
> We also need to change another user of enter_slow_path, xen_lock_spinning()
> in arch/x86/xen/spinlock.c.
>
Had in mind but forgot before sending. will update resend.
> Other than that looks correct at first glance... but this is up to
> maintainers.
>
Thanks
next prev parent reply other threads:[~2015-02-12 14:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-12 11:47 [PATCH V3] x86 spinlock: Fix memory corruption on completing completions Raghavendra K T
2015-02-12 13:37 ` Oleg Nesterov
2015-02-12 14:21 ` Raghavendra K T [this message]
2015-02-12 13:50 ` Oleg Nesterov
2015-02-12 14:23 ` Raghavendra K T
2015-02-12 14:02 ` Oleg Nesterov
2015-02-12 14:25 ` Raghavendra K T
2015-02-12 15:00 ` Peter Zijlstra
2015-02-12 15:28 ` Raghavendra K T
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