[PATCH] pci: fix memory leak when virtio pci hotplug

[PATCH] pci: fix memory leak when virtio pci hotplug

[Zhiqiang Liu]

From: Feilong Lin <linfeilong@huawei.com>

Repeated hot-plugging of pci devices for a virtual
machine driven by virtio, we found that there is a
leak in kmalloc-4k, which was confirmed as the memory
of the pci_device structure. Then we found out that
it was missing pci_dev_put() after pci_get_slot() in
enable_slot() of acpiphp_glue.c.

Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
---
 drivers/pci/hotplug/acpiphp_glue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 3365c93abf0e..f031302ad401 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -533,6 +533,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
 			slot->flags &= ~SLOT_ENABLED;
 			continue;
 		}
+		pci_dev_put(dev);
 	}
 }

-- 
2.19.1

Re: [PATCH] pci: fix memory leak when virtio pci hotplug

[Wu Bo]

On 2021/3/21 23:29, Zhiqiang Liu wrote:
> From: Feilong Lin <linfeilong@huawei.com>
> 
> Repeated hot-plugging of pci devices for a virtual
> machine driven by virtio, we found that there is a
> leak in kmalloc-4k, which was confirmed as the memory
> of the pci_device structure. Then we found out that
> it was missing pci_dev_put() after pci_get_slot() in
> enable_slot() of acpiphp_glue.c.
> 
> Signed-off-by: Feilong Lin <linfeilong@huawei.com>
> Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> ---
>   drivers/pci/hotplug/acpiphp_glue.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 3365c93abf0e..f031302ad401 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -533,6 +533,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
>   			slot->flags &= ~SLOT_ENABLED;
>   			continue;
>   		}
> +		pci_dev_put(dev);
>   	}
>   }
> 
Reviewed-by: Wu Bo <wubo40@huawei.com>

Re: [PATCH] pci: fix memory leak when virtio pci hotplug

[Zhiqiang Liu]

friendly ping..

On 2021/3/22 10:43, Wu Bo wrote:
> On 2021/3/21 23:29, Zhiqiang Liu wrote:
>> From: Feilong Lin <linfeilong@huawei.com>
>>
>> Repeated hot-plugging of pci devices for a virtual
>> machine driven by virtio, we found that there is a
>> leak in kmalloc-4k, which was confirmed as the memory
>> of the pci_device structure. Then we found out that
>> it was missing pci_dev_put() after pci_get_slot() in
>> enable_slot() of acpiphp_glue.c.
>>
>> Signed-off-by: Feilong Lin <linfeilong@huawei.com>
>> Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
>> ---
>>   drivers/pci/hotplug/acpiphp_glue.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
>> index 3365c93abf0e..f031302ad401 100644
>> --- a/drivers/pci/hotplug/acpiphp_glue.c
>> +++ b/drivers/pci/hotplug/acpiphp_glue.c
>> @@ -533,6 +533,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
>>               slot->flags &= ~SLOT_ENABLED;
>>               continue;
>>           }
>> +        pci_dev_put(dev);
>>       }
>>   }
>>
> Reviewed-by: Wu Bo <wubo40@huawei.com>
>
> .

Re: [PATCH] pci: fix memory leak when virtio pci hotplug

[Bjorn Helgaas]

On Sun, Mar 21, 2021 at 11:29:30PM +0800, Zhiqiang Liu wrote:
> From: Feilong Lin <linfeilong@huawei.com>
> 
> Repeated hot-plugging of pci devices for a virtual
> machine driven by virtio, we found that there is a
> leak in kmalloc-4k, which was confirmed as the memory
> of the pci_device structure. Then we found out that
> it was missing pci_dev_put() after pci_get_slot() in
> enable_slot() of acpiphp_glue.c.
> 
> Signed-off-by: Feilong Lin <linfeilong@huawei.com>
> Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>

Since this came from you, Zhiqiang, it needs a signed-off-by (not just
a reviewed-by) from you.  See
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=v5.11#n361

Also see
https://lore.kernel.org/r/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
and

  - Wrap commit log to fill 80 columns
  - s/pci/PCI/ (subject and commit log)
  - Run "git log --oneline drivers/pci/hotplug/acpiphp_glue.c".  It's
    not completely consistent, but at least match the style of one of
    them.

There is no "pci_device" structure.  I think you mean the "struct
pci_dev".

The commit log doesn't actually say what the patch does.  It's obvious
from the patch, but it should say in the commit log.  Look at previous
commit logs to see how they do it.

> ---
>  drivers/pci/hotplug/acpiphp_glue.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 3365c93abf0e..f031302ad401 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -533,6 +533,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
>  			slot->flags &= ~SLOT_ENABLED;
>  			continue;
>  		}
> +		pci_dev_put(dev);
>  	}
>  }
> 
> -- 
> 2.19.1
> 
> 

Re: [PATCH] pci: fix memory leak when virtio pci hotplug

[Zhiqiang Liu]

Thanks for your suggestion.

I will rewrite the commit log and send the v2 patch.


On 2021/3/24 2:24, Bjorn Helgaas wrote:
> On Sun, Mar 21, 2021 at 11:29:30PM +0800, Zhiqiang Liu wrote:
>> From: Feilong Lin <linfeilong@huawei.com>
>>
>> Repeated hot-plugging of pci devices for a virtual
>> machine driven by virtio, we found that there is a
>> leak in kmalloc-4k, which was confirmed as the memory
>> of the pci_device structure. Then we found out that
>> it was missing pci_dev_put() after pci_get_slot() in
>> enable_slot() of acpiphp_glue.c.
>>
>> Signed-off-by: Feilong Lin <linfeilong@huawei.com>
>> Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> Since this came from you, Zhiqiang, it needs a signed-off-by (not just
> a reviewed-by) from you.  See
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=v5.11#n361
>
> Also see
> https://lore.kernel.org/r/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
> and
>
>   - Wrap commit log to fill 80 columns
>   - s/pci/PCI/ (subject and commit log)
>   - Run "git log --oneline drivers/pci/hotplug/acpiphp_glue.c".  It's
>     not completely consistent, but at least match the style of one of
>     them.
>
> There is no "pci_device" structure.  I think you mean the "struct
> pci_dev".
>
> The commit log doesn't actually say what the patch does.  It's obvious
> from the patch, but it should say in the commit log.  Look at previous
> commit logs to see how they do it.
>
>> ---
>>  drivers/pci/hotplug/acpiphp_glue.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
>> index 3365c93abf0e..f031302ad401 100644
>> --- a/drivers/pci/hotplug/acpiphp_glue.c
>> +++ b/drivers/pci/hotplug/acpiphp_glue.c
>> @@ -533,6 +533,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
>>  			slot->flags &= ~SLOT_ENABLED;
>>  			continue;
>>  		}
>> +		pci_dev_put(dev);
>>  	}
>>  }
>>
>> -- 
>> 2.19.1
>>
>>
> .