Re: [PATCH rdma-next] RDMA/core: Skip initialized but not leaked GID entries

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2024/9/4 23:34, Leon Romanovsky 写道:
> On Wed, Sep 04, 2024 at 11:31:13AM -0300, Jason Gunthorpe wrote:
>> On Mon, Sep 02, 2024 at 04:42:52PM +0300, Leon Romanovsky wrote:
>>> From: Leon Romanovsky <leonro@nvidia.com>
>>>
>>> Failure in driver initialization can lead to a situation where the GID
>>> entries are set but not used yet. In this case, the kref will be equal to 1,
>>> which will trigger a false positive leak detection.
>>
>> Why does that happen??
>>
>>
>>> For example, these messages are printed during the driver initialization
>>> and followed by release_gid_table() call:
>>>
>>>   infiniband syz1: ib_query_port failed (-19)
>>>   infiniband syz1: Couldn't set up InfiniBand P_Key/GID cache
>>
>> Okay, but who set the ref=1?
>>
>>> diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c
>>> index b7c078b7f7cf..c6aec2e04d4c 100644
>>> --- a/drivers/infiniband/core/cache.c
>>> +++ b/drivers/infiniband/core/cache.c
>>> @@ -800,13 +800,15 @@ static void release_gid_table(struct ib_device *device,
>>>   		return;
>>>   
>>>   	for (i = 0; i < table->sz; i++) {
>>> +		int gid_kref;
>>> +
>>>   		if (is_gid_entry_free(table->data_vec[i]))
>>>   			continue;
>>>   
>>> -		WARN_ONCE(true,
>>> +		gid_kref = kref_read(&table->data_vec[i]->kref);
>>> +		WARN_ONCE(gid_kref > 1,
>>>   			  "GID entry ref leak for dev %s index %d ref=%u\n",
>>> -			  dev_name(&device->dev), i,
>>> -			  kref_read(&table->data_vec[i]->kref));
>>> +			  dev_name(&device->dev), i, gid_kref);
>>>   	}
>>
>> I'm not convinced, I think the bug here is something wrong on the
>> refcounting side not the freeing side. Ref should not be 1. Seems like
>> missing error unwinding in the init side.
> 
> I dropped this patch as the real fix is here 1403c8b14765 ("IB/core: Fix ib_cache_setup_one error flow cleanup")

The commit 1403c8b14765 ("IB/core: Fix ib_cache_setup_one error flow 
cleanup") is in the link 
https://patchwork.kernel.org/project/linux-rdma/patch/79137687d829899b0b1c9835fcb4b258004c439a.1725273354.git.leon@kernel.org/

Zhu Yanjun

> 
> Thanks
> 
>>
>> Jason
>>