[dpdk-dev] kni: error release device list head could cause a kernel crash.
Commit Message
From 3edca1e3194959ba26a6c36143f8423009661b11 Mon Sep 17 00:00:00 2001
From: zhouyangchao <zhouyates@gmail.com>
Date: Sat, 6 Aug 2016 19:14:51 +0800
Subject: [PATCH] kni: error release device list head could cause a kernel crash.
Signed-off-by: zhouyangchao <zhouyates@gmail.com>
---
lib/librte_eal/linuxapp/kni/kni_misc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--
Comments
Hi,
On 8/6/2016 12:19 PM, 周杨超 wrote:
> From 3edca1e3194959ba26a6c36143f8423009661b11 Mon Sep 17 00:00:00 2001
> From: zhouyangchao <zhouyates@gmail.com>
> Date: Sat, 6 Aug 2016 19:14:51 +0800
> Subject: [PATCH] kni: error release device list head could cause a kernel crash.
>
> Signed-off-by: zhouyangchao <zhouyates@gmail.com>
> ---
> lib/librte_eal/linuxapp/kni/kni_misc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c
> b/lib/librte_eal/linuxapp/kni/kni_misc.c
> index ae8133f..a49924b 100644
> --- a/lib/librte_eal/linuxapp/kni/kni_misc.c
> +++ b/lib/librte_eal/linuxapp/kni/kni_misc.c
> @@ -276,8 +276,8 @@ kni_release(struct inode *inode, struct file *file)
> #ifdef RTE_KNI_VHOST
> kni_vhost_backend_release(dev);
> #endif
> - kni_dev_remove(dev);
> list_del(&dev->list);
> + kni_dev_remove(dev);
> }
> up_write(&knet->kni_list_lock);
>
> @@ -613,8 +613,8 @@ kni_ioctl_release(struct net *net,
> #ifdef RTE_KNI_VHOST
> kni_vhost_backend_release(dev);
> #endif
> - kni_dev_remove(dev);
> list_del(&dev->list);
> + kni_dev_remove(dev);
> ret = 0;
> break;
> }
> --
>
Can you please describe how crash can occur?
And if you have a crash log, can you include it?
Access to device via list, removing device from list and adding device
to list all are protected by lock (kni_list_lock), so as far as I can
see the order of removing device and removing it from list shouldn't be
a problem.
Thanks,
ferruh
On 8/8/2016 12:48 PM, Ferruh Yigit wrote:
> Hi,
>
> On 8/6/2016 12:19 PM, 周杨超 wrote:
>> From 3edca1e3194959ba26a6c36143f8423009661b11 Mon Sep 17 00:00:00 2001
>> From: zhouyangchao <zhouyates@gmail.com>
>> Date: Sat, 6 Aug 2016 19:14:51 +0800
>> Subject: [PATCH] kni: error release device list head could cause a kernel crash.
>>
>> Signed-off-by: zhouyangchao <zhouyates@gmail.com>
>> ---
>> lib/librte_eal/linuxapp/kni/kni_misc.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c
>> b/lib/librte_eal/linuxapp/kni/kni_misc.c
>> index ae8133f..a49924b 100644
>> --- a/lib/librte_eal/linuxapp/kni/kni_misc.c
>> +++ b/lib/librte_eal/linuxapp/kni/kni_misc.c
>> @@ -276,8 +276,8 @@ kni_release(struct inode *inode, struct file *file)
>> #ifdef RTE_KNI_VHOST
>> kni_vhost_backend_release(dev);
>> #endif
>> - kni_dev_remove(dev);
>> list_del(&dev->list);
>> + kni_dev_remove(dev);
>> }
>> up_write(&knet->kni_list_lock);
>>
>> @@ -613,8 +613,8 @@ kni_ioctl_release(struct net *net,
>> #ifdef RTE_KNI_VHOST
>> kni_vhost_backend_release(dev);
>> #endif
>> - kni_dev_remove(dev);
>> list_del(&dev->list);
>> + kni_dev_remove(dev);
>> ret = 0;
>> break;
>> }
>> --
>>
>
> Can you please describe how crash can occur?
> And if you have a crash log, can you include it?
>
> Access to device via list, removing device from list and adding device
> to list all are protected by lock (kni_list_lock), so as far as I can
> see the order of removing device and removing it from list shouldn't be
> a problem.
I have sent a patch to fix a crash in remove path, if you are working on
master branch this can be same issue, can you please check following patch:
http://dpdk.org/dev/patchwork/patch/15571/
Regards,
ferruh
b/lib/librte_eal/linuxapp/kni/kni_misc.c
@@ -276,8 +276,8 @@ kni_release(struct inode *inode, struct file *file)
#ifdef RTE_KNI_VHOST
kni_vhost_backend_release(dev);
#endif
- kni_dev_remove(dev);
list_del(&dev->list);
+ kni_dev_remove(dev);
}
up_write(&knet->kni_list_lock);
@@ -613,8 +613,8 @@ kni_ioctl_release(struct net *net,
#ifdef RTE_KNI_VHOST
kni_vhost_backend_release(dev);
#endif
- kni_dev_remove(dev);
list_del(&dev->list);
+ kni_dev_remove(dev);
ret = 0;
break;
}