[bug report] scsi: core: Release SCSI devices synchronously

[bug report] scsi: core: Release SCSI devices synchronously

[Dan Carpenter]

Hello Bart Van Assche,

The patch f93ed747e2c7: "scsi: core: Release SCSI devices
synchronously" from Oct 14, 2022, leads to the following three Smatch
static checker warnings:

1) drivers/scsi/bfa/bfad_bsg.c:2551 bfad_iocmd_lunmask_reset_lunscan_mode() warn: sleeping in atomic context

bfad_iocmd_lunmask() <- disables preempt
-> bfad_iocmd_lunmask_reset_lunscan_mode()
   -> scsi_device_put()

(This is inside the calls to bfad_reset_sdev_bflags() macro).

2) drivers/scsi/device_handler/scsi_dh_alua.c:853 alua_rtpg_select_sdev() warn: sleeping in atomic context

alua_rtpg_work() <- disables preempt
-> alua_rtpg_select_sdev()
   -> scsi_device_put()

3) drivers/scsi/device_handler/scsi_dh_alua.c:1013 alua_rtpg_queue() warn: sleeping in atomic context

alua_check_vpd() <- disables preempt
-> alua_rtpg_queue()
   -> scsi_device_put()

Hopefully, this bug report is straight forward.  The fixes are probably
complicated though.  :P Basically the function marked "disables preempt"
takes a spin lock and calls the other function which calls
scsi_device_put().

regards,
dan carpenter

Re: [bug report] scsi: core: Release SCSI devices synchronously

[Bart Van Assche]

On 10/26/22 06:58, Dan Carpenter wrote:
> Hello Bart Van Assche,
> 
> The patch f93ed747e2c7: "scsi: core: Release SCSI devices
> synchronously" from Oct 14, 2022, leads to the following three Smatch
> static checker warnings:
> 
> 1) drivers/scsi/bfa/bfad_bsg.c:2551 bfad_iocmd_lunmask_reset_lunscan_mode() warn: sleeping in atomic context
> 
> bfad_iocmd_lunmask() <- disables preempt
> -> bfad_iocmd_lunmask_reset_lunscan_mode()
>     -> scsi_device_put()
> 
> (This is inside the calls to bfad_reset_sdev_bflags() macro).
> 
> 2) drivers/scsi/device_handler/scsi_dh_alua.c:853 alua_rtpg_select_sdev() warn: sleeping in atomic context
> 
> alua_rtpg_work() <- disables preempt
> -> alua_rtpg_select_sdev()
>     -> scsi_device_put()
> 
> 3) drivers/scsi/device_handler/scsi_dh_alua.c:1013 alua_rtpg_queue() warn: sleeping in atomic context
> 
> alua_check_vpd() <- disables preempt
> -> alua_rtpg_queue()
>     -> scsi_device_put()
> 
> Hopefully, this bug report is straight forward.  The fixes are probably
> complicated though.  :P Basically the function marked "disables preempt"
> takes a spin lock and calls the other function which calls
> scsi_device_put().

Thanks Dan for the detailed report. I plan to post fixes for these 
issues soon.

Bart.