Re: [PATCH V2 1/1] scsi: ufs: Fix a possible NULL pointer issue

[Can Guo <cang@codeaurora.org>]

On 2020-12-14 22:32, Bean Huo wrote:
> On Sun, 2020-12-13 at 19:41 -0800, Can Guo wrote:
>> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM
>> events and async scan")
>> 
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 9 +++++----
>>  1 file changed, 5 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index c1c401b..ef155a9 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -8883,8 +8883,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
>>         int ret = 0;
>>         ktime_t start = ktime_get();
>> 
>> +       if (!hba)
>> +               return 0;
>> +
>>         down(&hba->eh_sem);
>> -       if (!hba || !hba->is_powered)
>> +       if (!hba->is_powered)
>>                 return 0;
> 
> 
> Can,
> 
> why not moving down(&hba->eh_sem) after "return 0;"?

In your way, if hba is not powered, ufshcd_system_suspend() returns
0, which is a successful suspend. When ufshcd_system_resume() is called,
if hba is not powered, it goes to out and does up(&hba->eh_sem), which
shall cause unbalance to eh_sem.

Thanks,

Can Guo.