Re: kern/52331: ydc driver: sleep-under-spin-mutex bugs in yds_allocmem

[Robert Elz <kre%munnari.OZ.AU@localhost>]

The following reply was made to PR kern/52331; it has been noted by GNATS.

From: Robert Elz <kre%munnari.OZ.AU@localhost>
To: Jia-Ju Bai <baijiaju1990%163.com@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost
Subject: Re: kern/52331: ydc driver: sleep-under-spin-mutex bugs in yds_allocmem
Date: Sun, 25 Jun 2017 21:08:33 +0700

     Date:        Sun, 25 Jun 2017 21:14:19 +0800
     From:        Jia-Ju Bai <baijiaju1990%163.com@localhost>
     Message-ID:  <594FB72B.4050202%163.com@localhost>
 
   | From your words, I can see that "if (KERNADDR(p) == NULL)" is always 
   | not satisfied at runtime, is it?
 
 That happens (KERNADDR(p) == NULL) when yds_init() is called the first
 time from yds_attach().  That time no resources are yet allocated, and
 yds_allocmem() needs to allocate them.
 
 But that call is not from a context where sleeping is not allowed.
 
   | If it is, I think it is okay to remove the code (including yds_allocmem) 
   | of this if condition.
 
 So, no, the code is still needed, it is called, just not in the case of
 concern (I think, we need to wait and see what nat@ says about just
 how audio.c might influence things.)
 
 kre