Re: v4.3-rc2 dm-mq bug

[Bart Van Assche <bart.vanassche@sandisk.com>]

On 09/24/2015 04:01 PM, Mike Snitzer wrote:
> I'm not referring to the removal of a DM mpath device's underlying SRP
> paths.  The __dm_destroy() path is only used when destroying a DM
> device.  The only DM device used by multipath is the DM mpath device.
>
> So somehow your test is running the equivalent of:
>   dmsetup remove <toplevel_DM_mpath_device>
>
> While IO is being issued directly to that device.

Hello Mike,

One of the steps in my test is to remove all dm devices that have been 
created on top of SRP paths. The call trace at the start of this thread 
was triggered by the following command (unloading the SRP initiator is 
only possible after all holders of SRP paths have been removed):

for p in /sys/class/srp_remote_ports/*; do echo 1 >$p/delete & done; 
wait; dmsetup remove_all; modprobe -r ib_srp

The I/O was probably generated by multipathd itself (a path check).

Bart.