Re: [PATCH v2] scsi: target: tcm_loop: Fix NULL ptr dereference

[Mike Christie <michael.christie@oracle.com>]

On 4/23/26 8:39 PM, Guixin Liu wrote:
> The TCM_LOOP LUN creation process calls device_register() to create the
> device, which in turn invokes tcm_loop_driver_probe() registered with
> the TCM_LOOP bus to create and register the scsi_host.
> However, if the scsi_host memory allocation fails or scsi_add_host()
> fails, the device_register() process still returns success.
> Subsequently, when the user binds the LUN to a specific backend device,
> it accesses the NULL or freed scsi_host.
> 
> Crash Call Trace:
>   RIP: 0010:scsi_is_host_device+0x7/0x20
>   scsi_alloc_target+0x32/0x2c0
>   __scsi_add_device+0x41/0xf0
>   scsi_add_device+0xd/0x30
>   tcm_loop_port_link+0x25/0x50 [tcm_loop]
>   target_fabric_port_link+0x9c/0xb0 [target_core_mod]
>   ...
> 
> This issue is fixed by:
>   1. Setting the tcm_loop_hba's scsi_host to NULL, if
>      scsi_add_host() fails.
>   2. Checking the tcm_loop_hba's scsi_host after device_register().
>   3. Checking the tcm_loop_hba's scsi_host in tcm_loop_driver_remove().
> 
> Fixes: 3703b2c5d041 ("[SCSI] tcm_loop: Add multi-fabric Linux/SCSI LLD fabric module")
> Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>


Reviewed-by: Mike Christie <michael.christie@oracle.com>