The following reply was made to PR kern/34892; it has been noted by GNATS.

From: yamt@mwd.biglobe.ne.jp (YAMAMOTO Takashi)
To: gnats-bugs@NetBSD.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
	netbsd-bugs@netbsd.org
Subject: Re: kern/34892: panic: lockmgr: no context, when freeing sigacts in
 exit1()
Date: Tue, 12 Dec 2006 15:50:09 +0900 (JST)

 > >Number:         34892
 > >Category:       kern
 > >Synopsis:       panic: lockmgr: no context
 
 > >Description:
 > panic: lockmgr: no context
 > Stopped at      netbsd:cpu_Debugger+0x4:        leave
 > db> t
 > cpu_Debugger(ce3eda0c,e044,ce3eda2c,ce3eda18,10022) at netbsd:cpu_Debugger+0x4
 > panic(c07f874b,e09934b4,ce3eda5c,c036a31c,ce3eda48) at netbsd:panic+0x141
 > lockmgr(c08de9a4,10022,c08dea4c,81,c263f780) at netbsd:lockmgr+0x861
 > uvm_unmap1(c08de9a0,fac40000,fac60000,2800000,0) at netbsd:uvm_unmap1+0x4d
 > km_vacache_free(c08dea78,fac40000,74629163,ce3edad0,44d) at netbsd:km_vacache_free+0x29
 > pool_allocator_free(c08de9a0,fac40000,ce3edb04,ce3edb04,cf7db350) at netbsd:pool_allocator_free+0xe
 > pr_pagelist_free(44d,0,ce3edb4c,fac40fdc,0) at netbsd:pr_pagelist_free+0x34
 > pool_put(c08dea78,fac40000,ce3edb74,0,44d) at netbsd:pool_put+0x28
 > pool_allocator_free(0,0,ce3edb64,ce3edb64,cf7db350) at netbsd:pool_allocator_free+0xe
 > pr_pagelist_free(0,0,0,0,0) at netbsd:pr_pagelist_free+0x34
 > pool_put(c08fd8c0,fac40404,ce3edbfc,246,cf7db350) at netbsd:pool_put+0x28
 > sigactsfree(fac40404,cf7db350,ce3edbfc,c03dc5af,1000) at netbsd:sigactsfree+0x2a
 > exit1(de5eaf50,0,e32c8d0c,de5eaf50,0) at netbsd:exit1+0x3ca
 > sys_exit(de5eaf50,ce3edc48,ce3edc68,0,bbbcc000) at netbsd:sys_exit+0x31
 > syscall_plain() at netbsd:syscall_plain+0x155
 > --- syscall (number 1) ---
 > 0xbbbc693f:
 
 the problem is that, while pool_put is considered as non-sleepable by
 many of callers, freeing the kva into kernel_map needs to sleep.
 i think the similar problem can happen with pool_get(NOWAIT),
 when it involves pool_reclaim.
 
 for long term, i want to replace in-kernel kva allocator with vmem,
 so that freeing non-pageable kva doesn't need to sleep.  ie. register only
 pageable mappings to kernel_map.
 
 YAMAMOTO Takashi