[PATCH] drivers: nvdimm: fix dereference after free

[PATCH] drivers: nvdimm: fix dereference after free

[Konstantin Meskhidze]

'nd_pmu->pmu.attr_groups' is dereferenced in function
'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
after 'nvdimm_pmu_free_hotplug_memory'.

Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@huawei-partners.com>
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
---
 drivers/nvdimm/nd_perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
index 14881c4e0..2b6dc80d8 100644
--- a/drivers/nvdimm/nd_perf.c
+++ b/drivers/nvdimm/nd_perf.c
@@ -307,10 +307,10 @@ int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev)
 	}
 
 	rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->pmu.name, -1);
 	if (rc) {
-		kfree(nd_pmu->pmu.attr_groups);
 		nvdimm_pmu_free_hotplug_memory(nd_pmu);
+		kfree(nd_pmu->pmu.attr_groups);
 		return rc;
 	}
 
 	pr_info("%s NVDIMM performance monitor support registered\n",
-- 
2.34.1

Re: [PATCH] drivers: nvdimm: fix dereference after free

[Jeff Moyer]

Konstantin Meskhidze <konstantin.meskhidze@huawei.com> writes:

> 'nd_pmu->pmu.attr_groups' is dereferenced in function
> 'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
> function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
> 'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
> after 'nvdimm_pmu_free_hotplug_memory'.
>
> Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@huawei-partners.com>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
> ---
>  drivers/nvdimm/nd_perf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
> index 14881c4e0..2b6dc80d8 100644
> --- a/drivers/nvdimm/nd_perf.c
> +++ b/drivers/nvdimm/nd_perf.c
> @@ -307,10 +307,10 @@ int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev)
>  	}
>  
>  	rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->pmu.name, -1);
>  	if (rc) {
> -		kfree(nd_pmu->pmu.attr_groups);
>  		nvdimm_pmu_free_hotplug_memory(nd_pmu);
> +		kfree(nd_pmu->pmu.attr_groups);
>  		return rc;
>  	}
>  
>  	pr_info("%s NVDIMM performance monitor support registered\n",

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

Re: [PATCH] drivers: nvdimm: fix dereference after free

[Dave Jiang]

On 8/17/23 04:41, Konstantin Meskhidze wrote:
> 'nd_pmu->pmu.attr_groups' is dereferenced in function
> 'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
> function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
> 'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
> after 'nvdimm_pmu_free_hotplug_memory'.
> 
> Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@huawei-partners.com>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>

LGTM

Does this need a Fixes tag?

> ---
>   drivers/nvdimm/nd_perf.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
> index 14881c4e0..2b6dc80d8 100644
> --- a/drivers/nvdimm/nd_perf.c
> +++ b/drivers/nvdimm/nd_perf.c
> @@ -307,10 +307,10 @@ int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev)
>   	}
>   
>   	rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->pmu.name, -1);
>   	if (rc) {
> -		kfree(nd_pmu->pmu.attr_groups);
>   		nvdimm_pmu_free_hotplug_memory(nd_pmu);
> +		kfree(nd_pmu->pmu.attr_groups);
>   		return rc;
>   	}
>   
>   	pr_info("%s NVDIMM performance monitor support registered\n",

RE: [PATCH] drivers: nvdimm: fix dereference after free

[Dan Williams]

[ add Kajol ]

Konstantin Meskhidze wrote:
> 'nd_pmu->pmu.attr_groups' is dereferenced in function
> 'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
> function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
> 'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
> after 'nvdimm_pmu_free_hotplug_memory'.

Another one that would be fixed by static attribute groups.

I do think we should move forward with these fixes as is for ease of backport,
but long term this dynamically allocated attribute groups approach needs to be
jettisoned. ...unless I am missing a concrete reason it needs to remain dynamic?

Re: [PATCH] drivers: nvdimm: fix dereference after free

[Dave Jiang]

On 8/17/23 08:45, Dave Jiang wrote:
> 
> 
> On 8/17/23 04:41, Konstantin Meskhidze wrote:
>> 'nd_pmu->pmu.attr_groups' is dereferenced in function
>> 'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
>> function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
>> 'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
>> after 'nvdimm_pmu_free_hotplug_memory'.
>>
>> Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@huawei-partners.com>
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
> 
> LGTM
> 
> Does this need a Fixes tag?

Applied. Modified subject to "nvdimm: Fix dereference after free in 
register_nvdimm_pmu()"

Also added Fixes tag:
Fixes: 0fab1ba6ad6b ("drivers/nvdimm: Add perf interface to expose 
nvdimm performance stats")


> 
>> ---
>>   drivers/nvdimm/nd_perf.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
>> index 14881c4e0..2b6dc80d8 100644
>> --- a/drivers/nvdimm/nd_perf.c
>> +++ b/drivers/nvdimm/nd_perf.c
>> @@ -307,10 +307,10 @@ int register_nvdimm_pmu(struct nvdimm_pmu 
>> *nd_pmu, struct platform_device *pdev)
>>       }
>>       rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->pmu.name, -1);
>>       if (rc) {
>> -        kfree(nd_pmu->pmu.attr_groups);
>>           nvdimm_pmu_free_hotplug_memory(nd_pmu);
>> +        kfree(nd_pmu->pmu.attr_groups);
>>           return rc;
>>       }
>>       pr_info("%s NVDIMM performance monitor support registered\n",
>