Re: [PATCH] [SCSI] libsas: remove expander from dev list on error

[Luben Tuikov]

----- Original Message -----

> From: Jack Wang <jack_wang@xxxxxxxxx>
> To: 'Luben Tuikov' <ltuikov@xxxxxxxxx>; 'James Bottomley' <James.Bottomley@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx
> Cc: 
> Sent: Tuesday, July 26, 2011 8:26 PM
> Subject: Re: [PATCH] [SCSI] libsas: remove expander from dev list on error
> 
> [PATCH] [SCSI] libsas: remove expander from dev list on error
>> 
>>  If expander discovery fails (sas_discover_expander()),
>>  remove the expander from the port device list
>>  (sas_ex_discover_expander()), before freeing it. Else
>>  the list is corrupted and, e.g., when we attempt to send
>>  SMP commands to other devices, the kernel oopses.
>> 
>>  Signed-off-by: Luben Tuikov <ltuikov@xxxxxxxxx>
>>  ---
>>   drivers/scsi/libsas/sas_expander.c |    3 +++
>>   1 files changed, 3 insertions(+), 0 deletions(-)
>> 
>>  diff --git a/drivers/scsi/libsas/sas_expander.c
>>  b/drivers/scsi/libsas/sas_expander.c
>>  index 874e29d..f84084b 100644
>>  --- a/drivers/scsi/libsas/sas_expander.c
>>  +++ b/drivers/scsi/libsas/sas_expander.c
>>  @@ -849,6 +849,9 @@ static struct domain_device *sas_ex_discover_expander(
>> 
>>       res = sas_discover_expander(child);
>>       if (res) {
>>  +        spin_lock_irq(&parent->port->dev_list_lock);
>>  +        list_del(&child->dev_list_node);
>>  +        spin_unlock_irq(&parent->port->dev_list_lock);
>>           kfree(child);
>>           return NULL;
>>       }
>>  --
> [Jack Wang] Looks reasonable, thanks for fix this.
> You can add my Reviewed-by: Jack Wang <jack_wang@xxxxxxxxx> if needed.

Thanks.

Out of curiosity I took a look at my original code from 2005, before Bottomley changed it off git. This bug doesn't happen as the device is added to the port device list only when it is also registered with kobj. I guess that's a moot point now.

    Luben
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