kernel panic due to a missing work initialization in case of zero kato value

[Engel, Amit]

Hello,

We hit a kernel panic as a result of the below sequence:
In the current nvmet implementation, as part of 'nvmet_start_keep_alive_timer'
nvmet_keep_alive_timer work will be initialized only if kato != 0

when nvme connect cmd is being executed with a zero kato value
'INIT_DELAYED_WORK(&ctrl->ka_work, nvmet_keep_alive_timer)' will not be called

once keep alive cmd arrives, we call 'mod_delayed_work' for a work that has not been initialized
this will lead to kernel WARNING:
Apr 20 10:32:59 FNM00190700796-A kernel: WARNING: CPU: 11 PID: 75133 at kernel/workqueue.c:1447 __queue_work.cold.55+0xc/0x3c
And eventually to soft lockup

A simple fix for this issue (I will post a patch soon) is to initialize the work (as part of 'nvmet_start_keep_alive_timer') even if kato == 0

Thanks
Amit E