user-mode-linux-user

[uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

The following is reproduce able at my system -a ny hints ? :

$ /home/tfoerste/workspace/bin/start_uml.sh -r /home/tfoerste/virtual/uml/n22stab4 
Cannot get wake-on-lan settings: Operation not permitted
Locating the bottom of the address space ... 0x1000
Locating the top of the address space ... 0xc0000000
Core dump limits :
        soft - NONE
        hard - NONE
Checking that ptrace can change system call numbers...OK
Checking syscall emulation patch for ptrace...OK
Checking advanced syscall emulation patch for ptrace...OK
Checking for tmpfs mount on /dev/shm...OK
Checking PROT_EXEC mmap in /dev/shm/...OK
Checking for the skas3 patch in the host:
  - /proc/mm...not found: No such file or directory
  - PTRACE_FAULTINFO...not found
  - PTRACE_LDT...not found
UML running in SKAS0 mode
Adding 3014656 bytes to physical memory to account for exec-shield gap
bootconsole [earlycon0] enabled
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 768448k available
SLUB: Genslabs=15, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:15
Calibrating delay loop... 6447.10 BogoMIPS (lpj=32235520)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512
Checking for host processor cmov support...Yes
Checking that host ptys support output SIGIO...Yes
Checking that host ptys support SIGIO on close...No, enabling workaround
devtmpfs: initialized
Using 2.6 host AIO
NET: Registered protocol family 16
bio: create slab <bio-0> at 0
Switching to clocksource itimer
NET: Registered protocol family 2
TCP established hash table entries: 8192 (order: 4, 65536 bytes)
TCP bind hash table entries: 8192 (order: 3, 32768 bytes)
TCP: Hash tables configured (established 8192 bind 8192)
TCP: reno registered
UDP hash table entries: 512 (order: 1, 8192 bytes)
UDP-Lite hash table entries: 512 (order: 1, 8192 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
mconsole (version 2) initialized on /home/tfoerste/.uml/uml/mconsole
Checking host MADV_REMOVE support...OK
UML Audio Relay (host dsp = /dev/sound/dsp, host mixer = /dev/sound/mixer)
Host TLS support detected
Detected host type: i386 (GDT indexes 6 to 9)
audit: initializing netlink socket (disabled)
type=2000 audit(1362435381.156:1): initialized
NFS: Registering the id_resolver key type
Key type id_resolver registered
Key type id_legacy registered
nfs4filelayout_init: NFSv4 File Layout Driver Registering...
Installing knfsd (copyright (C) 1996 ok...@mo...).
msgmni has been set to 1500
alg: No test for stdrng (krng)
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254)
io scheduler noop registered (default)
tun: Universal TUN/TAP device driver, 1.6
tun: (C) 1999-2004 Max Krasnyansky <ma...@qu...>
device-mapper: uevent: version 1.0.3
device-mapper: ioctl: 4.23.1-ioctl (2012-12-18) initialised: dm-...@re...
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, bootconsole disabled
console [tty0] enabled, bootconsole disabled
                                            Initializing software serial port version 1
console [mc-1] enabled
 ubda: unknown partition table
 ubdb: unknown partition table
Netdevice 0 (72:ef:3d:fd:4a:0b) : 
TUN/TAP backend - 
EXT3-fs (ubda): error: couldn't mount because of unsupported optional features (240)
EXT2-fs (ubda): error: couldn't mount because of unsupported optional features (244)
EXT4-fs (ubda): INFO: recovery required on readonly filesystem
EXT4-fs (ubda): write access will be enabled during recovery
EXT4-fs (ubda): orphan cleanup on readonly fs
EXT4-fs (ubda): 5 orphan inodes deleted
EXT4-fs (ubda): recovery complete
EXT4-fs (ubda): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
devtmpfs: mounted
INIT: version 2.88 booting

   OpenRC 0.11.8 is starting up Gentoo Linux (i686) [UML]

 * Mounting /proc ...
 [ ok ]
 * Mounting /run ...
 * /run/openrc: creating directory
 * /run/lock: creating directory
 * /run/lock: correcting owner

EIP: 0073:[<00000000>] CPU: 0 Not tainted ESP: 007b:0840b800 EFLAGS: 00010246                       
    Not tainted                                                                                     
EAX: 00000000 EBX: 08416788 ECX: 08416788 EDX: 0840d3c0                                             
ESI: 0840bb0c EDI: 0840bba0 EBP: 0840b80c DS: 007b ES: 007b                                         
0840af4c:  [<0807957f>] show_regs+0x10f/0x120                                                       
0840af68:  [<08062163>] segv+0x293/0x2b0                                                            
0840b018:  [<080621f3>] segv_handler+0x73/0x80                                                      
0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0                                                
0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50                                                       
0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0                                                      
0840b2fc:  [<b77b140c>] 0xb77b140c                                                                  
0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
0840b830:  [<080623c9>] winch+0x19/0x20
0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
0840bafc:  [<b77b140c>] 0xb77b140c

Kernel panic - not syncing: Kernel mode fault at addr 0x0, ip 0x0
0840af28:  [<0833ea18>] dump_stack+0x22/0x24
0840af40:  [<0833ea94>] panic+0x7a/0x18b
0840af68:  [<0806217a>] segv+0x2aa/0x2b0
0840b018:  [<080621f3>] segv_handler+0x73/0x80
0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0
0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50
0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0
0840b2fc:  [<b77b140c>] 0xb77b140c
0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
0840b830:  [<080623c9>] winch+0x19/0x20
0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
0840bafc:  [<b77b140c>] 0xb77b140c


EIP: 0073:[<40001282>] CPU: 0 Not tainted ESP: 007b:bfd428fc EFLAGS: 00010206
    Not tainted
EAX: 00000000 EBX: 01200011 ECX: 00000000 EDX: 00000000
ESI: 00000000 EDI: 40261be8 EBP: bfd42978 DS: 007b ES: 007b
0840aedc:  [<0807957f>] show_regs+0x10f/0x120
0840aef8:  [<0806255c>] panic_exit+0x2c/0x50
0840af08:  [<0809e1f8>] notifier_call_chain+0x38/0x60
0840af30:  [<0809e343>] atomic_notifier_call_chain+0x23/0x30
0840af40:  [<0833eabc>] panic+0xa2/0x18b
0840af68:  [<0806217a>] segv+0x2aa/0x2b0
0840b018:  [<080621f3>] segv_handler+0x73/0x80
0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0
0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50
0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0
0840b2fc:  [<b77b140c>] 0xb77b140c
0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
0840b830:  [<080623c9>] winch+0x19/0x20
0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
0840bafc:  [<b77b140c>] 0xb77b140c

Terminated

-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Pierluigi R. <pie...@gm...>]

Hi,
UML user here. I'm able to reproduce a similar crash 100% of the time
with a 3.7 UML kernel if I configure my UML consoles some specific
way. I don't remember all the details of it. I think what's going on
here is that UML gets a signal it can't handle when you resize. Not
attaching to a pts (or anything else that generates those signals, a
serial port or a socket should be ok) should fix it. It is still quite
annoying, though.

HTH,
Pierluigi

On Mon, Mar 4, 2013 at 2:18 PM, Toralf Förster <tor...@gm...> wrote:
> The following is reproduce able at my system -a ny hints ? :
>
> $ /home/tfoerste/workspace/bin/start_uml.sh -r /home/tfoerste/virtual/uml/n22stab4
> Cannot get wake-on-lan settings: Operation not permitted
> Locating the bottom of the address space ... 0x1000
> Locating the top of the address space ... 0xc0000000
> Core dump limits :
>         soft - NONE
>         hard - NONE
> Checking that ptrace can change system call numbers...OK
> Checking syscall emulation patch for ptrace...OK
> Checking advanced syscall emulation patch for ptrace...OK
> Checking for tmpfs mount on /dev/shm...OK
> Checking PROT_EXEC mmap in /dev/shm/...OK
> Checking for the skas3 patch in the host:
>   - /proc/mm...not found: No such file or directory
>   - PTRACE_FAULTINFO...not found
>   - PTRACE_LDT...not found
> UML running in SKAS0 mode
> Adding 3014656 bytes to physical memory to account for exec-shield gap
> bootconsole [earlycon0] enabled
> PID hash table entries: 4096 (order: 2, 16384 bytes)
> Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
> Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
> Memory: 768448k available
> SLUB: Genslabs=15, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
> NR_IRQS:15
> Calibrating delay loop... 6447.10 BogoMIPS (lpj=32235520)
> pid_max: default: 32768 minimum: 301
> Mount-cache hash table entries: 512
> Checking for host processor cmov support...Yes
> Checking that host ptys support output SIGIO...Yes
> Checking that host ptys support SIGIO on close...No, enabling workaround
> devtmpfs: initialized
> Using 2.6 host AIO
> NET: Registered protocol family 16
> bio: create slab <bio-0> at 0
> Switching to clocksource itimer
> NET: Registered protocol family 2
> TCP established hash table entries: 8192 (order: 4, 65536 bytes)
> TCP bind hash table entries: 8192 (order: 3, 32768 bytes)
> TCP: Hash tables configured (established 8192 bind 8192)
> TCP: reno registered
> UDP hash table entries: 512 (order: 1, 8192 bytes)
> UDP-Lite hash table entries: 512 (order: 1, 8192 bytes)
> NET: Registered protocol family 1
> RPC: Registered named UNIX socket transport module.
> RPC: Registered udp transport module.
> RPC: Registered tcp transport module.
> RPC: Registered tcp NFSv4.1 backchannel transport module.
> mconsole (version 2) initialized on /home/tfoerste/.uml/uml/mconsole
> Checking host MADV_REMOVE support...OK
> UML Audio Relay (host dsp = /dev/sound/dsp, host mixer = /dev/sound/mixer)
> Host TLS support detected
> Detected host type: i386 (GDT indexes 6 to 9)
> audit: initializing netlink socket (disabled)
> type=2000 audit(1362435381.156:1): initialized
> NFS: Registering the id_resolver key type
> Key type id_resolver registered
> Key type id_legacy registered
> nfs4filelayout_init: NFSv4 File Layout Driver Registering...
> Installing knfsd (copyright (C) 1996 ok...@mo...).
> msgmni has been set to 1500
> alg: No test for stdrng (krng)
> Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254)
> io scheduler noop registered (default)
> tun: Universal TUN/TAP device driver, 1.6
> tun: (C) 1999-2004 Max Krasnyansky <ma...@qu...>
> device-mapper: uevent: version 1.0.3
> device-mapper: ioctl: 4.23.1-ioctl (2012-12-18) initialised: dm-...@re...
> 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, bootconsole disabled
> console [tty0] enabled, bootconsole disabled
>                                             Initializing software serial port version 1
> console [mc-1] enabled
>  ubda: unknown partition table
>  ubdb: unknown partition table
> Netdevice 0 (72:ef:3d:fd:4a:0b) :
> TUN/TAP backend -
> EXT3-fs (ubda): error: couldn't mount because of unsupported optional features (240)
> EXT2-fs (ubda): error: couldn't mount because of unsupported optional features (244)
> EXT4-fs (ubda): INFO: recovery required on readonly filesystem
> EXT4-fs (ubda): write access will be enabled during recovery
> EXT4-fs (ubda): orphan cleanup on readonly fs
> EXT4-fs (ubda): 5 orphan inodes deleted
> EXT4-fs (ubda): recovery complete
> EXT4-fs (ubda): mounted filesystem with ordered data mode. Opts: (null)
> VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
> devtmpfs: mounted
> INIT: version 2.88 booting
>
>    OpenRC 0.11.8 is starting up Gentoo Linux (i686) [UML]
>
>  * Mounting /proc ...
>  [ ok ]
>  * Mounting /run ...
>  * /run/openrc: creating directory
>  * /run/lock: creating directory
>  * /run/lock: correcting owner
>
> EIP: 0073:[<00000000>] CPU: 0 Not tainted ESP: 007b:0840b800 EFLAGS: 00010246
>     Not tainted
> EAX: 00000000 EBX: 08416788 ECX: 08416788 EDX: 0840d3c0
> ESI: 0840bb0c EDI: 0840bba0 EBP: 0840b80c DS: 007b ES: 007b
> 0840af4c:  [<0807957f>] show_regs+0x10f/0x120
> 0840af68:  [<08062163>] segv+0x293/0x2b0
> 0840b018:  [<080621f3>] segv_handler+0x73/0x80
> 0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840b2fc:  [<b77b140c>] 0xb77b140c
> 0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
> 0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
> 0840b830:  [<080623c9>] winch+0x19/0x20
> 0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840bafc:  [<b77b140c>] 0xb77b140c
>
> Kernel panic - not syncing: Kernel mode fault at addr 0x0, ip 0x0
> 0840af28:  [<0833ea18>] dump_stack+0x22/0x24
> 0840af40:  [<0833ea94>] panic+0x7a/0x18b
> 0840af68:  [<0806217a>] segv+0x2aa/0x2b0
> 0840b018:  [<080621f3>] segv_handler+0x73/0x80
> 0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840b2fc:  [<b77b140c>] 0xb77b140c
> 0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
> 0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
> 0840b830:  [<080623c9>] winch+0x19/0x20
> 0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840bafc:  [<b77b140c>] 0xb77b140c
>
>
> EIP: 0073:[<40001282>] CPU: 0 Not tainted ESP: 007b:bfd428fc EFLAGS: 00010206
>     Not tainted
> EAX: 00000000 EBX: 01200011 ECX: 00000000 EDX: 00000000
> ESI: 00000000 EDI: 40261be8 EBP: bfd42978 DS: 007b ES: 007b
> 0840aedc:  [<0807957f>] show_regs+0x10f/0x120
> 0840aef8:  [<0806255c>] panic_exit+0x2c/0x50
> 0840af08:  [<0809e1f8>] notifier_call_chain+0x38/0x60
> 0840af30:  [<0809e343>] atomic_notifier_call_chain+0x23/0x30
> 0840af40:  [<0833eabc>] panic+0xa2/0x18b
> 0840af68:  [<0806217a>] segv+0x2aa/0x2b0
> 0840b018:  [<080621f3>] segv_handler+0x73/0x80
> 0840b040:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840b2c4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840b2d4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840b2fc:  [<b77b140c>] 0xb77b140c
> 0840b810:  [<080c8408>] generic_handle_irq+0x28/0x30
> 0840b820:  [<0805ee55>] do_IRQ+0x25/0x40
> 0840b830:  [<080623c9>] winch+0x19/0x20
> 0840b840:  [<08071ab8>] sig_handler_common+0xb8/0xe0
> 0840bac4:  [<08071bfd>] sig_handler+0x3d/0x50
> 0840bad4:  [<0807174b>] hard_handler+0x6b/0xa0
> 0840bafc:  [<b77b140c>] 0xb77b140c
>
> Terminated
>
> --
> MfG/Sincerely
> Toralf Förster
> pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
>
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Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/05/2013 01:51 AM, Pierluigi Rolando wrote:
>  I think what's going on
> here is that UML gets a signal it can't handle when you resize.

Yes - something _is_ wrong with the signal handling, but my command line looks not suspicous, or ? :
/usr/local/bin/linux-v3.8.2 earlyprintk ubda=/home/tfoerste/virtual/uml/n22stab4 ubdb=/mnt/ramdisk/swap_n22stab4 eth0=tuntap,tap0,72:ef:3d:fd:4a:0b mem=768M umid=uml

-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Tue, Mar 5, 2013 at 4:33 PM, Toralf Förster <tor...@gm...> wrote:
> On 03/05/2013 01:51 AM, Pierluigi Rolando wrote:
>>  I think what's going on
>> here is that UML gets a signal it can't handle when you resize.
>
> Yes - something _is_ wrong with the signal handling, but my command line looks not suspicous, or ? :
> /usr/local/bin/linux-v3.8.2 earlyprintk ubda=/home/tfoerste/virtual/uml/n22stab4 ubdb=/mnt/ramdisk/swap_n22stab4 >eth0=tuntap,tap0,72:ef:3d:fd:4a:0b mem=768M umid=uml

I bet the attached patch makes the problem go away.
Please confirm.

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/05/2013 06:30 PM, richard -rw- weinberger wrote:
> On Tue, Mar 5, 2013 at 4:33 PM, Toralf Förster <tor...@gm...> wrote:
>> On 03/05/2013 01:51 AM, Pierluigi Rolando wrote:
>>>  I think what's going on
>>> here is that UML gets a signal it can't handle when you resize.
>>
>> Yes - something _is_ wrong with the signal handling, but my command line looks not suspicous, or ? :
>> /usr/local/bin/linux-v3.8.2 earlyprintk ubda=/home/tfoerste/virtual/uml/n22stab4 ubdb=/mnt/ramdisk/swap_n22stab4 >eth0=tuntap,tap0,72:ef:3d:fd:4a:0b mem=768M umid=uml
> 
> I bet the attached patch makes the problem go away.
> Please confirm.
> 
negative - applied on top of v3.9-rc1 :

diff --git a/arch/um/drivers/stdio_console.c b/arch/um/drivers/stdio_console.c
index 827777a..7b361f3 100644
--- a/arch/um/drivers/stdio_console.c
+++ b/arch/um/drivers/stdio_console.c
@@ -110,7 +110,6 @@ static const struct tty_operations console_ops = {
        .set_termios            = line_set_termios,
        .throttle               = line_throttle,
        .unthrottle             = line_unthrottle,
-       .cleanup                = line_cleanup,
        .hangup                 = line_hangup,
 };




- but issue still there :

VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
devtmpfs: mounted
INIT: version 2.88 booting

EIP: 0073:[<0808c0a8>] CPU: 0 Not tainted ESP: 007b:0840f768 EFLAGS: 00010202                       
    Not tainted                                                                                     
EAX: 00000004 EBX: 3958b800 ECX: 00000001 EDX: fffffffd                                             
ESI: 395788c0 EDI: 0000001c EBP: 0840f780 DS: 007b ES: 007b                                         
0840eecc:  [<0807921f>] show_regs+0x10f/0x120                                                       
0840eee8:  [<08061f12>] segv+0x62/0x2b0                                                             
0840ef98:  [<080621d3>] segv_handler+0x73/0x80                                                      
0840efc0:  [<080719d8>] sig_handler_common+0xb8/0xe0                                                
0840f244:  [<08071b1d>] sig_handler+0x3d/0x50                                                       
0840f254:  [<0807166b>] hard_handler+0x6b/0xa0                                                      
0840f27c:  [<b775440c>] 0xb775440c                                                                  
0840f784:  [<0808c3b6>] kill_pgrp+0x26/0x30
0840f798:  [<08064de3>] winch_interrupt+0xf3/0x120
0840f7bc:  [<080c7b0f>] handle_irq_event_percpu+0x2f/0x150
0840f7ec:  [<080c7c57>] handle_irq_event+0x27/0x40
0840f800:  [<080c9f60>] handle_edge_irq+0xd0/0x100
0840f810:  [<080c74c8>] generic_handle_irq+0x28/0x30
0840f820:  [<0805ee55>] do_IRQ+0x25/0x40
0840f830:  [<080623a9>] winch+0x19/0x20
0840f840:  [<080719d8>] sig_handler_common+0xb8/0xe0
0840fac4:  [<08071b1d>] sig_handler+0x3d/0x50
0840fad4:  [<0807166b>] hard_handler+0x6b/0xa0
0840fafc:  [<b775440c>] 0xb775440c

Kernel panic - not syncing: Segfault with no mm
0840eea8:  [<08342658>] dump_stack+0x22/0x24
0840eec0:  [<083426d4>] panic+0x7a/0x18b
0840eee8:  [<08061f1e>] segv+0x6e/0x2b0
0840ef98:  [<080621d3>] segv_handler+0x73/0x80
0840efc0:  [<080719d8>] sig_handler_common+0xb8/0xe0
0840f244:  [<08071b1d>] sig_handler+0x3d/0x50
0840f254:  [<0807166b>] hard_handler+0x6b/0xa0
0840f27c:  [<b775440c>] 0xb775440c
0840f784:  [<0808c3b6>] kill_pgrp+0x26/0x30
0840f798:  [<08064de3>] winch_interrupt+0xf3/0x120
0840f7bc:  [<080c7b0f>] handle_irq_event_percpu+0x2f/0x150
0840f7ec:  [<080c7c57>] handle_irq_event+0x27/0x40
0840f800:  [<080c9f60>] handle_edge_irq+0xd0/0x100
0840f810:  [<080c74c8>] generic_handle_irq+0x28/0x30
0840f820:  [<0805ee55>] do_IRQ+0x25/0x40
0840f830:  [<080623a9>] winch+0x19/0x20
0840f840:  [<080719d8>] sig_handler_common+0xb8/0xe0
0840fac4:  [<08071b1d>] sig_handler+0x3d/0x50
0840fad4:  [<0807166b>] hard_handler+0x6b/0xa0
0840fafc:  [<b775440c>] 0xb775440c


EIP: 0000:[<00000000>] CPU: 0 Not tainted EFLAGS: 00000000
    Not tainted
EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000
ESI: 00000000 EDI: 00000000 EBP: 00000000 DS: 0000 ES: 0000
0840ee5c:  [<0807921f>] show_regs+0x10f/0x120
0840ee78:  [<0806253c>] panic_exit+0x2c/0x50
0840ee88:  [<0809d1d8>] notifier_call_chain+0x38/0x60
0840eeb0:  [<0809d323>] atomic_notifier_call_chain+0x23/0x30
0840eec0:  [<083426fc>] panic+0xa2/0x18b
0840eee8:  [<08061f1e>] segv+0x6e/0x2b0
0840ef98:  [<080621d3>] segv_handler+0x73/0x80
0840efc0:  [<080719d8>] sig_handler_common+0xb8/0xe0
0840f244:  [<08071b1d>] sig_handler+0x3d/0x50
0840f254:  [<0807166b>] hard_handler+0x6b/0xa0
0840f27c:  [<b775440c>] 0xb775440c
0840f784:  [<0808c3b6>] kill_pgrp+0x26/0x30
0840f798:  [<08064de3>] winch_interrupt+0xf3/0x120
0840f7bc:  [<080c7b0f>] handle_irq_event_percpu+0x2f/0x150
0840f7ec:  [<080c7c57>] handle_irq_event+0x27/0x40
0840f800:  [<080c9f60>] handle_edge_irq+0xd0/0x100
0840f810:  [<080c74c8>] generic_handle_irq+0x28/0x30
0840f820:  [<0805ee55>] do_IRQ+0x25/0x40
0840f830:  [<080623a9>] winch+0x19/0x20
0840f840:  [<080719d8>] sig_handler_common+0xb8/0xe0
0840fac4:  [<08071b1d>] sig_handler+0x3d/0x50
0840fad4:  [<0807166b>] hard_handler+0x6b/0xa0
0840fafc:  [<b775440c>] 0xb775440c

Terminated

-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Tue, Mar 5, 2013 at 6:57 PM, Toralf Förster <tor...@gm...> wrote:
> On 03/05/2013 06:30 PM, richard -rw- weinberger wrote:
>> On Tue, Mar 5, 2013 at 4:33 PM, Toralf Förster <tor...@gm...> wrote:
>>> On 03/05/2013 01:51 AM, Pierluigi Rolando wrote:
>>>>  I think what's going on
>>>> here is that UML gets a signal it can't handle when you resize.
>>>
>>> Yes - something _is_ wrong with the signal handling, but my command line looks not suspicous, or ? :
>>> /usr/local/bin/linux-v3.8.2 earlyprintk ubda=/home/tfoerste/virtual/uml/n22stab4 ubdb=/mnt/ramdisk/swap_n22stab4 >eth0=tuntap,tap0,72:ef:3d:fd:4a:0b mem=768M umid=uml
>>
>> I bet the attached patch makes the problem go away.
>> Please confirm.
>>
> negative - applied on top of v3.9-rc1 :

What is your console? I suspect it is not stdio_console.
My first patch addressed only stdio_console...

Anyway, I took a closer look at the problem.
The issue was caused because of some tty_port changes.
The attached patch fixes the issue for me. I was able to reproduce it...

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/06/2013 12:32 AM, richard -rw- weinberger wrote:
> What is your console? I suspect it is not stdio_console.

I tried both with "con=pts con0=fd:0,fd:1" as well as without specifying
console/tty at the command line - no difference.

But for completeness I attached the .config I used

-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Wed, Mar 6, 2013 at 7:10 PM, Toralf Förster <tor...@gm...> wrote:
> On 03/06/2013 12:32 AM, richard -rw- weinberger wrote:
>> What is your console? I suspect it is not stdio_console.
>
> I tried both with "con=pts con0=fd:0,fd:1" as well as without specifying
> console/tty at the command line - no difference.
>
> But for completeness I attached the .config I used

Hmm, funny. There is a second issue which affects only i386.
/me looks.

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Wed, Mar 6, 2013 at 7:24 PM, richard -rw- weinberger
<ric...@gm...> wrote:
> On Wed, Mar 6, 2013 at 7:10 PM, Toralf Förster <tor...@gm...> wrote:
>> On 03/06/2013 12:32 AM, richard -rw- weinberger wrote:
>>> What is your console? I suspect it is not stdio_console.
>>
>> I tried both with "con=pts con0=fd:0,fd:1" as well as without specifying
>> console/tty at the command line - no difference.
>>
>> But for completeness I attached the .config I used
>
> Hmm, funny. There is a second issue which affects only i386.
> /me looks.

Found the issue. A very nasty use-after-free tty issue which happened
only sometimes.
Please test the attached patch.
/me tested x86_64 and x86 successfully.

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/07/2013 12:00 AM, richard -rw- weinberger wrote:
> Found the issue. A very nasty use-after-free tty issue which happened
> only sometimes.
> Please test the attached patch.
> /me tested x86_64 and x86 successfully.
> 
Today I tested a patched 3.9 kernel for the UML guest several times,
host kernel was 3.8.2. Later I realized a core file in my HOME directory.
I'm not sure whether this back trace helps :

...
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?
Core was generated by `/usr/local/bin/linux-v3.9-rc1-211-g47b3bc9 earlyprintk ubda=/home/tfoerste/virt'.
Program terminated with signal 11, Segmentation fault.
#0  constant_test_bit (nr=<optimized out>, addr=<optimized out>) at /home/tfoerste/devel/linux/arch/x86/include/asm/bitops.h:321
321                     (addr[nr / BITS_PER_LONG])) != 0;
(gdb) bt
#0  constant_test_bit (nr=<optimized out>, addr=<optimized out>) at /home/tfoerste/devel/linux/arch/x86/include/asm/bitops.h:321
#1  test_ti_thread_flag (ti=<optimized out>, flag=<optimized out>) at include/linux/thread_info.h:93
#2  test_tsk_thread_flag (flag=<optimized out>, tsk=<optimized out>) at include/linux/sched.h:2522
#3  signal_pending (p=<optimized out>) at include/linux/sched.h:2548
#4  __set_task_blocked (tsk=0x37ec0000, newset=0x37ec2f48) at kernel/signal.c:2524
#5  0x0808d003 in __set_current_blocked (newset=0x37ec2f48) at kernel/signal.c:2552
#6  0x0808d027 in set_current_blocked (newset=0x0) at kernel/signal.c:2544
#7  0x0808e584 in sigsuspend (set=0x0) at kernel/signal.c:3550
#8  0x08064668 in winch_thread (arg=0x0) at arch/um/drivers/chan_user.c:210
#9  0x46a6b41e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133
(gdb) quit




-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/07/2013 12:00 AM, richard -rw- weinberger wrote:
> On Wed, Mar 6, 2013 at 7:24 PM, richard -rw- weinberger
> <ric...@gm...> wrote:
>> On Wed, Mar 6, 2013 at 7:10 PM, Toralf Förster <tor...@gm...> wrote:
>>> On 03/06/2013 12:32 AM, richard -rw- weinberger wrote:
>>>> What is your console? I suspect it is not stdio_console.
>>>
>>> I tried both with "con=pts con0=fd:0,fd:1" as well as without specifying
>>> console/tty at the command line - no difference.
>>>
>>> But for completeness I attached the .config I used
>>
>> Hmm, funny. There is a second issue which affects only i386.
>> /me looks.
> 
> Found the issue. A very nasty use-after-free tty issue which happened
> only sometimes.
> Please test the attached patch.
> /me tested x86_64 and x86 successfully.
> 

issue is fixed here too - thx.

FWIW something like "con=pts con0=fd:0,fd:1" is now mandatory,
otherwise an xterm is open and user root can login, but I experienced
strange things with my Gentoo :

...
 * Caching service dependencies ...
Service `apache2' needs non existent service `net'
Service `bootmisc' needs non existent service `localmount'
                      [ ok ]
 * ERROR: bootmisc needs service(s) localmount
INIT: Entering runlevel: 3

 * ERROR: apache2 needs service(s) net
 * ERROR: bootmisc needs service(s) localmount
------------[ cut here ]------------

WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcab ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcac ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcad ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcae ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcaf ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb0 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb1 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb2 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb3 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb4 ]---
flush_to_ldisc: 2 callbacks suppressed
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb5 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb6 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb7 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb8 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
tty is NULL
3851fea0:  [<08342748>] dump_stack+0x22/0x24
3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
3851ff70:  [<0809355c>] worker_thread+0x25c/0x360
3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0
3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
3851fffc:  [<00000000>] 0x0

---[ end trace 42be3b31debefcb9 ]---
------------[ cut here ]------------
WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()

tty is NULL

3851fea0:  [<08342748>] dump_stack+0x22/0x24

3851feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80

3851fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30

3851fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190

3851ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0

3851ff70:  [<0809355c>] worker_thread+0x25c/0x360

3851ffa4:  [<08097fe2>] kthread+0xc2/0xd0

3851ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0

3851fffc:  [<00000000>] 0x0


---[ end trace 42be3b31debefcba ]---
INIT: Switching to runlevel: 0
INIT: Sending processes the TERM signal
System halted.


-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Thu, Mar 7, 2013 at 5:11 PM, Toralf Förster <tor...@gm...> wrote:
>> issue is fixed here too - thx.
>
> FWIW something like "con=pts con0=fd:0,fd:1" is now mandatory,
> otherwise an xterm is open and user root can login, but I experienced
> strange things with my Gentoo :

So, xterm is broken in 3.9-rc1?
Please bisect it.

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/07/2013 05:34 PM, richard -rw- weinberger wrote:
> So, xterm is broken in 3.9-rc1?
> Please bisect it.
> 
Cannot be reproduced under host kernel 3.7.10, and host kernel 3.8.2 suffers
from a complete hang if an (unprivileged) user starts UML and just wait for
a while (already reported to this list).
But what I do see under host 3.7.10 and
UML  3.9.0-rc1-00108-g9f22578-dirty (dirty == your patch)
is that this section is repeated many times in the UML syslog :


2013-03-07T18:23:59.185+01:00 n22stab4 kernel: WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: tty is NULL
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fea0:  [<08342748>] dump_stack+0x22/0x24
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ff70:  [<0809355c>] worker_thread+0x25c/0x360
2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ffa4:  [<08097fe2>] kthread+0xc2/0xd0
2013-03-07T18:23:59.187+01:00 n22stab4 kernel: 3979ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
2013-03-07T18:23:59.187+01:00 n22stab4 kernel: 3979fffc:  [<00000000>] 0x0
2013-03-07T18:23:59.187+01:00 n22stab4 kernel: 
2013-03-07T18:23:59.187+01:00 n22stab4 kernel: ---[ end trace fe7100411e1ca835 ]---



The command line to start the UML was :

/home/tfoerste/workspace/bin/start_uml.sh -r /home/tfoerste/virtual/uml/n22stab4  -l /usr/local/bin/linux-v3.9-rc1-108-g9f22578 
Cannot get wake-on-lan settings: Operation not permitted
+ /usr/local/bin/linux-v3.9-rc1-108-g9f22578 earlyprintk ubda=/home/tfoerste/virtual/uml/n22stab4 ubdb=/mnt/ramdisk/swap_n22stab4 eth0=tuntap,tap0,72:ef:3d:fd:4a:0b mem=768M con=pts con0=fd:0,fd:1 con1=xterm con12=xterm umid=uml

-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Thu, Mar 7, 2013 at 6:28 PM, Toralf Förster <tor...@gm...> wrote:
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: WARNING: at drivers/tty/tty_buffer.c:428 flush_to_ldisc+0x51/0x190()
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: tty is NULL
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fea0:  [<08342748>] dump_stack+0x22/0x24
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979feb8:  [<0807d0ea>] warn_slowpath_common+0x5a/0x80
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fee0:  [<0807d15e>] warn_slowpath_fmt+0x2e/0x30
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979fef8:  [<0827d6a1>] flush_to_ldisc+0x51/0x190
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ff2c:  [<0809254a>] process_one_work+0x1ba/0x2f0
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ff70:  [<0809355c>] worker_thread+0x25c/0x360
> 2013-03-07T18:23:59.185+01:00 n22stab4 kernel: 3979ffa4:  [<08097fe2>] kthread+0xc2/0xd0
> 2013-03-07T18:23:59.187+01:00 n22stab4 kernel: 3979ffec:  [<0805f84a>] new_thread_handler+0x7a/0xa0
> 2013-03-07T18:23:59.187+01:00 n22stab4 kernel: 3979fffc:  [<00000000>] 0x0
> 2013-03-07T18:23:59.187+01:00 n22stab4 kernel:
> 2013-03-07T18:23:59.187+01:00 n22stab4 kernel: ---[ end trace fe7100411e1ca835 ]---

BTW: This is not UML specific.
The WARN_ON() in tty_buffer.c will be removed, it is harmless.

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[richard -r. w. <ric...@gm...>]

On Thu, Mar 7, 2013 at 6:28 PM, Toralf Förster <tor...@gm...> wrote:
> On 03/07/2013 05:34 PM, richard -rw- weinberger wrote:
>> So, xterm is broken in 3.9-rc1?
>> Please bisect it.
>>
> Cannot be reproduced under host kernel 3.7.10, and host kernel 3.8.2 suffers
> from a complete hang if an (unprivileged) user starts UML and just wait for
> a while (already reported to this list).

Wait. The _host_ version of Linux plays a role?
Please more details.
Which pairs of UML/Host show this problem?

-- 
Thanks,
//richard

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/08/2013 11:14 AM, richard -rw- weinberger wrote:
> On Thu, Mar 7, 2013 at 6:28 PM, Toralf Förster <tor...@gm...> wrote:
>> On 03/07/2013 05:34 PM, richard -rw- weinberger wrote:
>>> So, xterm is broken in 3.9-rc1?
>>> Please bisect it.
>>>
>> Cannot be reproduced under host kernel 3.7.10, and host kernel 3.8.2 suffers
>> from a complete hang if an (unprivileged) user starts UML and just wait for
>> a while (already reported to this list).
> 
> Wait. The _host_ version of Linux plays a role?
> Please more details.
> Which pairs of UML/Host show this problem?
> 
host kernel 3.8.x shows that problem,
reproducible here with uml guests 3.7.10, 3.8.2 and 3.9-rc1+

host kernel 3.7.10 does not suffer from this problem.

I reported that to this list already because IMHO it is local
exploitable security flaw (if it can be reproduced at others systems
too), and  neither sudo nor any privileges are necessary to halt a
system. FWIW neither sys-rq nor any other key works, nothing in the
syslog, at the console or anything seen on the screen.



-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3

Re: [uml-user] resizing a KDE Konsole let a UML instance crash

[Toralf F. <tor...@gm...>]

On 03/08/2013 11:14 AM, richard -rw- weinberger wrote:
> On Thu, Mar 7, 2013 at 6:28 PM, Toralf Förster <tor...@gm...> wrote:
>> On 03/07/2013 05:34 PM, richard -rw- weinberger wrote:
>>> So, xterm is broken in 3.9-rc1?
>>> Please bisect it.
>>>
>> Cannot be reproduced under host kernel 3.7.10, and host kernel 3.8.2 suffers
>> from a complete hang if an (unprivileged) user starts UML and just wait for
>> a while (already reported to this list).
> 
> Wait. The _host_ version of Linux plays a role?
> Please more details.
> Which pairs of UML/Host show this problem?
> 
something in between 3.8.2 and 3.83 solves the issue, now I can run host
with 3.8.3 and UML guest with arbitrary kernel version (but heavily
testd just with current 3.9-rc2-... kernels) w/o this issue so far as I
can see.


-- 
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3