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* [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove
@ 2019-03-19 14:24 Marcin Dziegielewski
  2019-03-21  9:17 ` Javier González
  0 siblings, 1 reply; 3+ messages in thread
From: Marcin Dziegielewski @ 2019-03-19 14:24 UTC (permalink / raw)
  To: mb, javier, hans.holmberg
  Cc: linux-block, marcin.dziegielewski, igor.j.konopko

When we trigger nvm target remove during device hot unplug, we
have a chance to hit general protection fault caused by use of
nvm_dev which was freed from another (hot unplug) thread (in
nvm_unregister function).

This patch introduce lock in nvme_ioctl_dev_remove function to
prevent us before a situation like described above.

Signed-off-by: Marcin Dziegielewski <marcin.dziegielewski@intel.com>
---
 drivers/lightnvm/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 5f82036..84f0b9a 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -1335,11 +1335,13 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
 		return -EINVAL;
 	}
 
+	down_read(&nvm_lock);
 	list_for_each_entry(dev, &nvm_devices, devices) {
 		ret = nvm_remove_tgt(dev, &remove);
 		if (!ret)
 			break;
 	}
+	up_read(&nvm_lock);
 
 	return ret;
 }
-- 
1.8.3.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove
  2019-03-19 14:24 [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove Marcin Dziegielewski
@ 2019-03-21  9:17 ` Javier González
  2019-03-25 11:05   ` Matias Bjørling
  0 siblings, 1 reply; 3+ messages in thread
From: Javier González @ 2019-03-21  9:17 UTC (permalink / raw)
  To: Marcin Dziegielewski
  Cc: Matias Bjørling, Hans Holmberg, linux-block, Konopko, Igor J

[-- Attachment #1: Type: text/plain, Size: 1195 bytes --]

> On 19 Mar 2019, at 15.24, Marcin Dziegielewski <marcin.dziegielewski@intel.com> wrote:
> 
> When we trigger nvm target remove during device hot unplug, we
> have a chance to hit general protection fault caused by use of
> nvm_dev which was freed from another (hot unplug) thread (in
> nvm_unregister function).
> 
> This patch introduce lock in nvme_ioctl_dev_remove function to
> prevent us before a situation like described above.
> 
> Signed-off-by: Marcin Dziegielewski <marcin.dziegielewski@intel.com>
> ---
> drivers/lightnvm/core.c | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 5f82036..84f0b9a 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -1335,11 +1335,13 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
> 		return -EINVAL;
> 	}
> 
> +	down_read(&nvm_lock);
> 	list_for_each_entry(dev, &nvm_devices, devices) {
> 		ret = nvm_remove_tgt(dev, &remove);
> 		if (!ret)
> 			break;
> 	}
> +	up_read(&nvm_lock);
> 
> 	return ret;
> }
> --
> 1.8.3.1

Looks good to me.


Reviewed-by: Javier González <javier@javigon.com>


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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove
  2019-03-21  9:17 ` Javier González
@ 2019-03-25 11:05   ` Matias Bjørling
  0 siblings, 0 replies; 3+ messages in thread
From: Matias Bjørling @ 2019-03-25 11:05 UTC (permalink / raw)
  To: Javier González, Marcin Dziegielewski
  Cc: Hans Holmberg, linux-block, Konopko, Igor J

On 3/21/19 10:17 AM, Javier González wrote:
>> On 19 Mar 2019, at 15.24, Marcin Dziegielewski <marcin.dziegielewski@intel.com> wrote:
>>
>> When we trigger nvm target remove during device hot unplug, we
>> have a chance to hit general protection fault caused by use of
>> nvm_dev which was freed from another (hot unplug) thread (in
>> nvm_unregister function).
>>
>> This patch introduce lock in nvme_ioctl_dev_remove function to
>> prevent us before a situation like described above.
>>
>> Signed-off-by: Marcin Dziegielewski <marcin.dziegielewski@intel.com>
>> ---
>> drivers/lightnvm/core.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>> index 5f82036..84f0b9a 100644
>> --- a/drivers/lightnvm/core.c
>> +++ b/drivers/lightnvm/core.c
>> @@ -1335,11 +1335,13 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
>> 		return -EINVAL;
>> 	}
>>
>> +	down_read(&nvm_lock);
>> 	list_for_each_entry(dev, &nvm_devices, devices) {
>> 		ret = nvm_remove_tgt(dev, &remove);
>> 		if (!ret)
>> 			break;
>> 	}
>> +	up_read(&nvm_lock);
>>
>> 	return ret;
>> }
>> --
>> 1.8.3.1
> 
> Looks good to me.
> 
> 
> Reviewed-by: Javier González <javier@javigon.com>
> 

Thanks Marcin. I've reworded the description a bit before pulling it in.

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-03-25 11:05 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-03-19 14:24 [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove Marcin Dziegielewski
2019-03-21  9:17 ` Javier González
2019-03-25 11:05   ` Matias Bjørling

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