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Message-ID: <4D777CDA.3050500@univ-nantes.fr>
Date: Wed, 09 Mar 2011 14:12:58 +0100
From: Jean-Philippe Menil <jean-philippe.menil@...v-nantes.fr>
To: "Michael S. Tsirkin" <mst@...hat.com>
CC: netdev@...r.kernel.org, kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: Re: Bug inkvm_set_irq
Le 09/03/2011 14:00, Michael S. Tsirkin a écrit :
> On Wed, Mar 09, 2011 at 01:28:43PM +0100, Jean-Philippe Menil wrote:
>> Le 08/03/2011 12:13, Michael S. Tsirkin a écrit :
>>> On Fri, Mar 04, 2011 at 10:39:05AM +0100, Jean-Philippe Menil wrote:
>>>> Yes, it's a 2.6.37.2 kernel.
>>> OK, here's a debugging patch.
>>> Please run with slab debugging as previously until you see
>>> 'eventfd bug detected!' in dmesg or until there is a crash.
>>> It might be also useful to enable timestampts on printk with
>>> Symbol: PRINTK_TIME [=y]
>>> │ Type : boolean
>>> │ Prompt: Show timing information on printks
>>>
>>> once you see the error, please upload the
>>> full dmesg output somewhere to we can track what
>>> goes on.
>>>
>>> Hopefully there won't be an oops this time which
>>> should make it easier for you to test (no need to
>>> reboot).
>>>
>>>
>>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>>> index c1f1e3c..3cb679b 100644
>>> --- a/virt/kvm/eventfd.c
>>> +++ b/virt/kvm/eventfd.c
>>> @@ -32,6 +32,7 @@
>>> #include<linux/eventfd.h>
>>> #include<linux/kernel.h>
>>> #include<linux/slab.h>
>>> +#include<linux/nmi.h>
>>>
>>> #include "iodev.h"
>>>
>>> @@ -43,6 +44,8 @@
>>> * --------------------------------------------------------------------
>>> */
>>>
>>> +#define KVM_BAD_PTR ((void*)(long)(0x6b6b6b6b6b6b6b6bull))
>>> +
>>> struct _irqfd {
>>> struct kvm *kvm;
>>> struct eventfd_ctx *eventfd;
>>> @@ -61,6 +64,13 @@ irqfd_inject(struct work_struct *work)
>>> {
>>> struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
>>> struct kvm *kvm = irqfd->kvm;
>>> + if (kvm == KVM_BAD_PTR) {
>>> + printk(KERN_ERR "Eventfd bug detected!\n");
>>> + printk(KERN_ERR "%s(work=%p,irqfd=%p,kvm=%p,gsi=%d)\n", __func__,
>>> + work, irqfd, kvm, irqfd->gsi);
>>> + trigger_all_cpu_backtrace();
>>> + return;
>>> + }
>>>
>>> kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
>>> kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
>>> @@ -75,6 +85,8 @@ irqfd_shutdown(struct work_struct *work)
>>> struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
>>> u64 cnt;
>>>
>>> + printk(KERN_ERR "%s(work=%p,irqfd=%p,kvm=%p, gsi=%d)\n", __func__,
>>> + work, irqfd, irqfd->kvm, irqfd->gsi);
>>> /*
>>> * Synchronize with the wait-queue and unhook ourselves to prevent
>>> * further events.
>>> @@ -91,6 +103,8 @@ irqfd_shutdown(struct work_struct *work)
>>> * It is now safe to release the object's resources
>>> */
>>> eventfd_ctx_put(irqfd->eventfd);
>>> + printk(KERN_ERR "kfree at %s(work=%p,irqfd=%p)\n", __func__,
>>> + work, irqfd);
>>> kfree(irqfd);
>>> }
>>>
>>> @@ -111,6 +125,8 @@ static void
>>> irqfd_deactivate(struct _irqfd *irqfd)
>>> {
>>> BUG_ON(!irqfd_is_active(irqfd));
>>> + printk(KERN_ERR "%s(irqfd=%p,kvm=%p, gsi=%d)\n", __func__,
>>> + irqfd, irqfd->kvm, irqfd->gsi);
>>>
>>> list_del_init(&irqfd->list);
>>>
>>> @@ -178,6 +194,8 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
>>>
>>> irqfd->kvm = kvm;
>>> irqfd->gsi = gsi;
>>> + printk(KERN_ERR "%s(irqfd=%p,kvm=%p, gsi=%d)\n", __func__,
>>> + irqfd, kvm, gsi);
>>> INIT_LIST_HEAD(&irqfd->list);
>>> INIT_WORK(&irqfd->inject, irqfd_inject);
>>> INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
>>> @@ -264,6 +282,8 @@ kvm_irqfd_deassign(struct kvm *kvm, int fd, int gsi)
>>> struct _irqfd *irqfd, *tmp;
>>> struct eventfd_ctx *eventfd;
>>>
>>> + printk(KERN_ERR "%s(kvm=%p, gsi=%d)\n", __func__,
>>> + kvm, gsi);
>>> eventfd = eventfd_ctx_fdget(fd);
>>> if (IS_ERR(eventfd))
>>> return PTR_ERR(eventfd);
>>> @@ -305,6 +325,7 @@ void
>>> kvm_irqfd_release(struct kvm *kvm)
>>> {
>>> struct _irqfd *irqfd, *tmp;
>>> + printk(KERN_ERR "%s(kvm=%p)\n", __func__, kvm);
>>>
>>> spin_lock_irq(&kvm->irqfds.lock);
>>>
>>> --
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>> Hi,
>>
>> I boot the host with the patched kernel yesterday.
>> No crach until now, but two "Eventfd bug detected!" in the log at
>> "Mar 9 02:04:31" and "Mar 9 02:15:17"
>> You can find part of the log at the following adress:
>> http://filex.univ-nantes.fr/get?k=jL4Fe7yfSMN57toAH7V
>>
>> It a split file of the kern.log (1,4G), so if you need another part
>> of the log, let me know.
>>
>> Thanks for all.
>>
>> Regards.
> Downloading, it's big :)
> What about some 1000 lines before and after Eventfd bug detected! line?
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Yes, sorry about that.
I could have split my log into a smaller file.
I was a little afraid of not transmit enough informations, and i was a
bit wide.
I hope you can find usefull trace anyway.
Regards.
--
Jean-Philippe Menil - Pôle réseau Service IRTS
DSI Université de Nantes
jean-philippe.menil@...v-nantes.fr
Tel : 02.53.48.49.27 - Fax : 02.53.48.49.09
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