Re: kern/52858: kernel lock up

[coypu%sdf.org@localhost]

The following reply was made to PR kern/52858; it has been noted by GNATS.

From: coypu%sdf.org@localhost
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/52858: kernel lock up
Date: Mon, 25 Dec 2017 02:45:10 +0000

 It looks like we can spin forever in pool_catchup if we have PR_WAITOK
 allocation sleeping followed by a PR_NOWAIT allocation.
 
 
 Single CPU, no kpreemption arch
 
 [lwp #1]
    |
 [  ??  ]
    |
 [pool_grow with PR_WAITOK
 [set PR_GROWING
 [allocation, decide to sleep
    |
   zzZzzZ                          [lwp #2]
                                      |
                                   [  ??  ]
                                      |
                                   [pool_catchup with PR_NOWAIT
                                   [see PR_GROWING already set,
                                   [spin forever returning ERESTART
                                   [(nothing ever preempts me or
 				   increases the pool items)