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: Sun, 15 Mar 2015 17:51:21 +0100	[thread overview]
Message-ID: <5505B889.4020401@gmx.de> (raw)
In-Reply-To: <55059907.9060408@nod.at>

On 03/15/2015 03:36 PM, Richard Weinberger wrote:
> BTW: Just ran a x86 UML with CONFIG_MCORE2=y. Works perfectly fine.

The picture isn't clear.

After twiddling with the kernel config I got a working  .config with CORE2=y. This runs fine if compiled with vanilla gcc 4.8.3.

Compiled with the default (hardened) gcc it hangs as expected. After waiting a long time I do get :

$> /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
Locating the bottom of the address space ... 0x1000
Locating the top of the address space ... 0xffffd000
Core dump limits :
        soft - 0
        hard - NONE
...
device-mapper: ioctl: 4.30.0-ioctl (2014-12-22) initialised: dm-devel@redhat.com
TCP: cubic registered
NET: Registered protocol family 17
Key type dns_resolver registered
Initialized stdio console driver
Console initialized on /dev/tty0
                                console [tty0] enabled
console [tty0] enabled
                      bootconsole [earlycon0] disabled
bootconsole [earlycon0] disabled
                                Initializing software serial port version 1
console [mc-1] enabled
Netdevice 0 (72:ef:3d:9f:c3:5a) : 
TUN/TAP backend - 
Btrfs loaded
winch_thread : TIOCSCTTY failed on fd 1 err = 1
EXT4-fs (ubda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
devtmpfs: mounted
Stub registers -
        0 - 0
        1 - 101b7c
        2 - 101afc
        3 - 0
        4 - 0
        5 - 101ae8
        6 - b
        7 - 2b
        8 - 2b
        9 - 0
        10 - 0
        11 - ffffffff
        12 - 1000d9
        13 - 23
        14 - 10206
        15 - 100ad8
        16 - 2b
wait_stub_done : failed to wait for SIGTRAP, pid = 1420, n = 1420, errno = 0, status = 0xb7f
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

CPU: 0 PID: 1 Comm: init Not tainted 4.0.0-rc3-00222-g7cd9beb3 #3
Stack:
 0854eca5 0854eca5 085ae547 00000000 84c9fe24 84eb1c38 84c8bad0 084c9933
 00000000 84c8baa8 84c8baf8 084c61c0 0855b150 0868f580 0855b2ec 84c8bb08
 0810329a 84c9fe24 84eb1c38 84c98000 84c8bb38 08111881 0855b2ec 0000000b
Call Trace:
 [<080ef8c6>] show_stack+0xd6/0x1a0
 [<084c9933>] dump_stack+0x26/0x28
 [<084c61c0>] panic+0x7a/0x194
 [<0810329a>] ? unblock_signals+0x1a/0xa0
 [<08111881>] do_exit+0x9d1/0x9e0
 [<08117ee5>] ? recalc_sigpending+0x15/0x50
 [<08111907>] do_group_exit+0x37/0xc0
 [<0811a46b>] get_signal+0x18b/0x570
 [<08103599>] ? set_signals+0x19/0x60
 [<080ef466>] kern_do_signal+0x46/0x300
 [<0812ab00>] ? wake_up_state+0x10/0x20
 [<08118782>] ? signal_wake_up_state+0x22/0x30
 [<08118dcd>] ? __send_signal.constprop.29+0xfd/0x2b0
 [<081387f5>] ? vprintk_emit+0x205/0x450
 [<0810329a>] ? unblock_signals+0x1a/0xa0
 [<081035c8>] ? set_signals+0x48/0x60
 [<081197a5>] ? force_sig_info+0x95/0xb0
 [<080ef73a>] do_signal+0x1a/0x20
 [<080f0b85>] fatal_sigsegv+0x25/0x30
 [<0810678b>] wait_stub_done+0xeb/0x130
 [<0810683d>] get_skas_faultinfo.part.1+0x6d/0x100
 [<08106935>] get_skas_faultinfo+0x65/0x90
 [<0810c20d>] ? get_fp_registers+0x4d/0x60
 [<081070ca>] userspace+0x55a/0x650
 [<08199c54>] ? do_execve+0x24/0x30
 [<080ed01b>] ? run_init_process+0x2b/0x30
 [<080ed02f>] ? try_to_run_init_process+0xf/0x40
 [<08128652>] ? async_synchronize_full+0x22/0x30
 [<084c5d32>] ? kernel_init+0x92/0xd0
 [<080ee512>] new_thread_handler+0x82/0x90

/home/tfoerste/workspace/bin/start_uml.sh: line 104:  1351 Aborted                 $STRACE $LINUX earlyprintk ubda=$ROOTFS ubdb=$SWAP eth0=$NET mem=$MEM $TTY umid=uml_$NAME rootfstype=ext4 "$ARGS"

FWIW Gentoo give us the choice :

$ gcc-config  -l
 [1] x86_64-pc-linux-gnu-4.8.3 *
 [2] x86_64-pc-linux-gnu-4.8.3-hardenednopie
 [3] x86_64-pc-linux-gnu-4.8.3-hardenednopiessp
 [4] x86_64-pc-linux-gnu-4.8.3-hardenednossp
 [5] x86_64-pc-linux-gnu-4.8.3-vanilla

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

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