__rw_wlock_hard panic on 1st malloc

[Damjan Marion]

On Apr 18, 2013, at 10:08 AM, Andrew Turner <andrew at fubar.geek.nz> wrote:

> On Wed, 17 Apr 2013 22:36:29 -0600
> Warner Losh <imp at bsdimp.com> wrote:
> 
>> 
>> On Apr 17, 2013, at 7:36 PM, Andrew Turner wrote:
>> 
>>> On Wed, 17 Apr 2013 09:37:26 -0600
>>> Warner Losh <imp at bsdimp.com> wrote:
>>> 
>>>> I don't think it is, at least not with clang compiled code. Ian was
>>>> saying on IRC that he saw this and went back to gcc and life was
>>>> good.
>>> 
>>> I suspect it is an issue with the newer version of clang imported
>>> recently. I have tested with an old version of clang and an updated
>>> kernel and had no issues booting.
>> 
>> If I take WITNESS out of the kernel, I have no issues either. Not
>> sure what WITNESS' problem is...
> 
> I've tried with an updated clang on a PandaBoard with WITNESS enabled.
> The only issue I'm hitting is vm_thread_new fails, but this is after
> FreeBSD enters userland which, from you other emails, appears to be
> further than you are getting.
> 
> I have set unmapped_buf_allowed = 0 in sys/arm/arm/pmap-v6.c to work
> around the above stack issue. I don't know if this will fix the issue
> or not but you can try it to see.

Just tried clang + unmapped_buf_allowed=0:

Copyright (c) 1992-2013 The FreeBSD Project.
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FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 10.0-CURRENT #0 r+b594eb9-dirty: Thu Apr 18 09:29:34 CEST 2013
    dmarion at vm-freebsd-head:/tmp/WANDBOARD arm
FreeBSD clang version 3.3 (trunk 178860) 20130405
WARNING: WITNESS option enabled, expect reduced performance.
panic: acquiring blockable sleep lock with spinlock or critical section held (rw) pmap pv global @ /usr/src/sys/arm/arm/pmap-v6.c:1187
KDB: enter: panic

Damjan