Re: [PATCH V3 3/3] scsi: core: put ->shost_gendev.parent in failure handling path

[Hannes Reinecke <hare@suse.de>]

On 5/31/21 9:56 AM, Ming Lei wrote:
> On Mon, May 31, 2021 at 08:28:49AM +0200, Hannes Reinecke wrote:
>> On 5/31/21 7:07 AM, Ming Lei wrote:
>>> get_device(shost->shost_gendev.parent) is called in
>>> scsi_add_host_with_dma(), but its counter pair isn't called in the failure
>>> path, so fix it by calling put_device(shost->shost_gendev.parent) in its
>>> failure path.
>>>
>>> Reported-by: John Garry <john.garry@huawei.com>
>>> Cc: Bart Van Assche <bvanassche@acm.org>
>>> Cc: Hannes Reinecke <hare@suse.de>
>>> Signed-off-by: Ming Lei <ming.lei@redhat.com>
>>> ---
>>>    drivers/scsi/hosts.c | 1 +
>>>    1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
>>> index 6cbc3eb16525..6cc43c51b7b3 100644
>>> --- a/drivers/scsi/hosts.c
>>> +++ b/drivers/scsi/hosts.c
>>> @@ -298,6 +298,7 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
>>>     out_del_dev:
>>>    	device_del(&shost->shost_dev);
>>>     out_del_gendev:
>>> +	put_device(shost->shost_gendev.parent);
>>>    	device_del(&shost->shost_gendev);
>>>     out_disable_runtime_pm:
>>>    	device_disable_async_suspend(&shost->shost_gendev);
>>>
>> This really needs to be folded into the first patch as it's really a bugfix
>> for that.
> 
> All three are bug fixes, and this one may leak .shost_gendev's parent,
> but the 1st one leaks .shost_gendev->kobj.name, so we needn't to fold
> the 3rd into the 1st one.
> 
I beg to disagree.
The first patch removes the 'get_device()' from
scsi_add_host_with_dma(), but does not remove the corresponding 
'put_device()' in the error path.
So the first patch introduces a reference imbalance which is fixed by 
the third patch. Hence my suggestion to merge those two patches.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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