NetBSD Problem Report #46591

From he@smistad.uninett.no  Tue Jun 12 08:59:59 2012
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Date: Tue, 12 Jun 2012 10:59:54 +0200 (CEST)
From: he@NetBSD.org
Reply-To: he@NetBSD.org
To: gnats-bugs@gnats.NetBSD.org
Subject: Doing "ktrace -p <pid>" triggered panic
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>Number:         46591
>Category:       port-powerpc
>Synopsis:       Doing "ktrace -p <pid>" triggered panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-powerpc-maintainer
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 12 09:00:00 +0000 2012
>Closed-Date:    Fri Jul 06 13:10:51 +0000 2012
>Last-Modified:  Fri Jul 06 13:20:04 +0000 2012
>Originator:     Havard Eidnes
>Release:        NetBSD 6.0_BETA2
>Organization:
	None
>Environment:
System: NetBSD malus.urc.uninett.no 6.0_BETA2 NetBSD 6.0_BETA2 (GENERIC) #5: Wed May 30 20:32:20 CEST 2012  he@malus.urc.uninett.no:/usr/obj/sys/arch/macppc/compile/GENERIC macppc
Architecture: powerpc
Machine: macppc
>Description:
	During a pkgsrc bulk build, an awk process appeared to be
	spinning on the CPU checking for "porbability" of a Bourne
	shell script.  I wanted to see if it was doing any system
	calls, and what they were, so did a

	ktrace -p <pid>

	on the process, something which triggered an instant panic.

	This was what was left in the messages file after the machine
	came back up again:

panic: cpu_uarea_alloc: uvm_pglistalloc failed: 12
cpu0: Begin traceback...
0xd9d5bc40: at panic+0x4c
0xd9d5bc80: at cpu_uarea_alloc+0x78
0xd9d5bcb0: at uarea_system_poolpage_alloc+0x20
0xd9d5bcc0: at pool_grow+0x48
0xd9d5bce0: at pool_get+0x58
0xd9d5bd00: at pool_cache_get_slow+0x1a4
0xd9d5bd50: at pool_cache_get_paddr+0x104
0xd9d5bd90: at uvm_uarea_system_alloc+0x1c
0xd9d5bda0: at kthread_create+0x60
0xd9d5be00: at ktrace_common+0x390
0xd9d5be40: at sys_ktrace+0xf4
0xd9d5bec0: at syscall_plain+0x1f0
0xd9d5bf20: user SC trap #45 by 0xfde8120c: srr1=0xd032
           r1=0xffffd760 cr=0x28000044 xer=0x20000000 ctr=0xfde81204
cpu0: End traceback...
dumpsys: TBD
rebooting

	Since there doesn't appear to be any code to dump kernel core,
	that's all I'm left with.

	12 is ENOMEM.

	...and since uarea_system_poolpage_alloc() calls
	cpu_uarea_alloc with "true", it panics.  It appears that
	uarea_system_poolpage_alloc() is prepared to deal with a NULL
	return from cpu_uarea_alloc(), though, but on powerpc, it
	appears that cpu_uarea_alloc() will never return NULL, but
	will instead panic if called with system=true and there's a
	memory shortage "somewhere".

	This is different from x86, where the code doesn't check the
	"system" argument, and doesn't panic() inside
	cpu_uarea_alloc().

>How-To-Repeat:
	I'm not sure how repeatable this is...

>Fix:
	Sorry, don't know.

>Release-Note:

>Audit-Trail:
From: Havard Eidnes <he@NetBSD.org>
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: port-powerpc/46591: Doing "ktrace -p <pid>" triggered panic
Date: Thu, 28 Jun 2012 14:01:40 +0200 (CEST)

 Update: doing a simple

   ktrace -i sh some-script.sh

 also results in an instant panic.  The same one, it seems:

 panic: cpu_uarea_alloc: uvm_pglistalloc failed: 12
 cpu0: Begin traceback...
 0xd9d3bc40: at panic+0x4c
 0xd9d3bc80: at cpu_uarea_alloc+0x78
 0xd9d3bcb0: at uarea_system_poolpage_alloc+0x20
 0xd9d3bcc0: at pool_grow+0x48
 0xd9d3bce0: at pool_get+0x58
 0xd9d3bd00: at pool_cache_get_slow+0x1a4
 0xd9d3bd50: at pool_cache_get_paddr+0x104
 0xd9d3bd90: at uvm_uarea_system_alloc+0x1c
 0xd9d3bda0: at kthread_create+0x60
 0xd9d3be00: at ktrace_common+0x390
 0xd9d3be40: at sys_ktrace+0xf4
 0xd9d3bec0: at syscall_plain+0x1f0
 0xd9d3bf20: user SC trap #45 by 0xfde8120c: srr1=3D0xd032
             r1=3D0xffffd750 cr=3D0x28000044 xer=3D0x20000000 ctr=3D0xfd=
 e81204
 cpu0: End traceback...
 dumpsys: TBD
 rebooting

 Regards,

 - H=E5vard

State-Changed-From-To: open->closed
State-Changed-By: jdc@NetBSD.org
State-Changed-When: Fri, 06 Jul 2012 13:10:51 +0000
State-Changed-Why:
Fix committed with revision 1.97 of src/sys/arch/powerpc/powerpc/vm_machdep.c:
  http://mail-index.netbsd.org/source-changes/2012/06/28/msg035282.html
Pulled up to netbsd-6 in ticket #388.


From: "Julian Coleman" <jdc@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/46591 CVS commit: [netbsd-6] src/doc
Date: Fri, 6 Jul 2012 13:07:25 +0000

 Module Name:	src
 Committed By:	jdc
 Date:		Fri Jul  6 13:07:25 UTC 2012

 Modified Files:
 	src/doc [netbsd-6]: CHANGES-6.0

 Log Message:
 Mention PR port-powerpc/46591 in the entry for #388.


 To generate a diff of this commit:
 cvs rdiff -u -r1.1.2.151 -r1.1.2.152 src/doc/CHANGES-6.0

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

>Unformatted:

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