On 01/10/2015 06:45 PM, Richard Weinberger wrote:
> Am 10.01.2015 um 18:37 schrieb Toralf Förster:
>> On 01/10/2015 06:25 PM, Richard Weinberger wrote:
>>> Am 10.01.2015 um 17:08 schrieb Toralf Förster:
>>>> yes, it never worked with values above 2026M (tested at an old ThinkPad
>>>> T420, running a 32 bit Gentoo Linux with host kernel 3.17.4 )
>>>
>>> The theoretical max. was always 2GiB due to the limited address space on
>>> ia32.
>>> 2GiB - UML binary - ASLR overhead/padding is what you can use.
>>> But the "write: File too large" issue is something new. I bet it origins
>>> from tmpfs or shm on the host side.
>>>
>>> Thanks,
>>> //richard
>>>
>> Well, I already had explicitly to define the mount, b/c Gentoo's default is
>> "noexec":
>>
>> tfoerste@n22 ~ $ mount | grep shm
>> shm on /dev/shm type tmpfs (rw,nosuid,nodev,relatime)
>
> Can it carry a 2GiB file?
>
Ick, good hint, I set now the size to 3 GB :
tfoerste@t44 ~ $ ssh tfoerste@n22 grep shm /etc/fstab
shm /dev/shm tmpfs nodev,nosuid,size=3G
and tried after re-mounting with 2026M, but got :
$ start_uml.sh -r trinity
+ /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=2026M 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 ... 0xc0000000
Core dump limits :
soft - 0
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 environment variables for a tempdir...none found
Checking if /dev/shm is on tmpfs...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 13238272 bytes to physical memory to account for exec-shield gap
Kernel virtual memory size shrunk to 944766976 bytes
/home/tfoerste/workspace/bin/start_uml.sh: line 115: 4195 Segmentation fault
$LINUX earlyprintk ubda=$ROOTFS ubdb=$SWAP eth0=$NET mem=$MEM $TTY
umid=uml_$NAME rootfstype=ext4 "$ARGS"
+ RC=139
+ set +x
Nevertheless I tried again, it worked now. The limit is now 2031M as far as I
can tell.
--
Toralf
pgp key: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 0076 E94E
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