Re: [uml-devel] starting an 32 bit x86 chroot uml image at a ahrdened Gentoo amd64 system fails

From: "Toralf Förster" <toralf.foerster@gmx.de>
To: Richard Weinberger <richard@nod.at>
Cc: UML devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: Re: [uml-devel] starting an 32 bit x86 chroot uml image at a ahrdened Gentoo amd64 system fails
Date: Fri, 13 Mar 2015 14:40:37 +0100	[thread overview]
Message-ID: <5502E8D5.8040500@gmx.de> (raw)
In-Reply-To: <54FF606E.5050109@nod.at>

On 03/10/2015 10:21 PM, Richard Weinberger wrote:
> Am 10.03.2015 um 19:56 schrieb Toralf Förster:
>> On 03/10/2015 07:43 PM, Richard Weinberger wrote:
>>> Also please send me your .config.
>> attached
> 
> This .config works perfecly fine here.
> So, what does your userspace? Does UML crash while booting up?
> BTW: You do not specify mem=, so you have only very few memory...
> 
> Thanks,
> //richard
> 
Well,
in fact I never ever managed it to boot the UML guest here at my new hardened host.
But at elast (today) I get reliable a crash in the same place (again and again):

$ /home/tfoerste/devel/linux/linux earlyprintk ubda=/home/tfoerste/virtual/uml/trinity ubdb=/mnt/ramdisk/trinity_swap eth0=tuntap,tap0,72:ef:3d:9f:c3:5a mem=2000M con0=fd:0,fd:1 con=pts umid=uml_trinity rootfstype=ext4 softlockup_all_cpu_backtrace=1  

console [mc-1] enabled
Failed to initialize ubd device 1 :Couldn't determine size of device's file
Netdevice 0 (72:ef:3d:9f:c3:5a) : 
TUN/TAP backend - 
EXT4-fs (ubda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
devtmpfs: mounted

Modules linked in:
Pid: 1, comm: swapper Not tainted 4.0.0-rc3-00148-gc202baf
RIP: 0033:[<0000000060250c5e>]
RSP: 000003d3185f5f08  EFLAGS: 00010202
RAX: 0000000060250c4c RBX: 00000000606049c8 RCX: 000003d317f1db99
RDX: 00000000602356f0 RSI: 000003d3185f6fe8 RDI: 00000000dcdd6000
RBP: 000003d3185f6fe8 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000dc819778 R11: 0000000000000246 R12: 00000000dcdd6000
R13: 000003d3185f6000 R14: 0000000060235c00 R15: 00000000602d98b2
Kernel panic - not syncing: Segfault with no mm
CPU: 0 PID: 1 Comm: swapper Not tainted 4.0.0-rc3-00148-gc202baf #5
Stack:

Modules linked in:
Pid: 1, comm: swapper Not tainted 4.0.0-rc3-00148-gc202baf
RIP: 0033:[<0000000060238a51>]
RSP: 0000000060571450  EFLAGS: 00010202
RAX: 0000000000000006 RBX: 000000006049c59e RCX: 00000000606049c8
RDX: 0000000000000000 RSI: 0000000060613338 RDI: 0000000000000000
RBP: 0000000060571480 R08: 0000000060571059 R09: 000000006027eb6f
R10: 0000000000000008 R11: 00000000003b7039 R12: 000003d3185f5f0f
R13: 0000000000000001 R14: 00000000605716f0 R15: 0000000000000001
Kernel panic - not syncing: Segfault with no mm

which resolves now to
$ addr2line -e ./linux 0000000060250c5e
/home/tfoerste/devel/linux/arch/um/os-Linux/skas/process.c:199

$ addr2line -e ./linux 0000000060238a51
/home/tfoerste/devel/linux/arch/um/kernel/sysrq.c:56

-- 
Toralf
pgp key: 7B1A 07F4 EC82 0F90 D4C2  8936 872A E508 0076 E94E

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