Re: Problem with dosemu

Sorry to be so slow/indecisive, but is this not the old problem with
the memory fence pointer, which used to be fixable with the creation
of a file in /etc/sysctl.d/, say

/etc/sysctl.d/90-low-memory-access.conf

which contains the command

vm.mmap_min_addr=0.

One also needed to
keep the kernel from randomizing virtual address space with

echo 0 > /proc/sys/kernel/randomize_va_space

but I think that went away with 1.4 (??). I am not sure about any of
this with modern kernels because I run dosemu (1.4) on a 32-bit
ubuntu 9.04 virtual machine under 64-bit Fedora 19 for various complicated
reasons.

Hope this may help, and sorry if it is irrelevant.

--jim gunn

On Mon, 21 Apr 2014, jankomEarthlink wrote:

> Thank you, Franta, for getting back to this problem. In the meantime I ran 
> strace and googled the issue and saw some bug reports on this segmentation 
> fault. Here is the last part of the strace listing. (Btw., I'll try your rpm 
> tomorrow, it is getting late here, and I have to clean up my system again 
> before I install your rpm, and will let you know if it worked).
>
> [apu@Andraslinux ~]$ strace dosemu
> ...
> write(3, "PKT: Cannot open raw sockets: Pe"..., 48) = 48
> statfs("/dev/shm/", {f_type=0x1021994, f_bsize=4096, f_blocks=129447, 
> f_bfree=129447, f_bavail=129447, f_files=129447, f_ffree=129446, f_fsid={0, 
> 0}, f_namelen=255, f_frsize=4096}) = 0
> futex(0xd79258, FUTEX_WAKE, 2147483647) = 0
> open("/dev/shm/dosemu_3778", O_RDWR|O_CREAT|O_TRUNC|O_NOFOLLOW, 0600) = 4
> fcntl64(4, F_GETFD)                     = 0
> fcntl64(4, F_SETFD, FD_CLOEXEC)         = 0
> unlink("/dev/shm/dosemu_3778")          = 0
> ftruncate64(4, 0)                       = 0
> ftruncate64(4, 17891328)                = 0
> mmap2(NULL, 17891328, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) = 0xb6bbb000
> mprotect(0xb6bbb000, 17891328, PROT_READ|PROT_WRITE|PROT_EXEC) = 0
> mprotect(0xb6bbb000, 17891328, PROT_READ|PROT_WRITE) = 0
> mprotect(0xb6bbb000, 1114112, PROT_READ|PROT_WRITE) = 0
> mmap2(NULL, 1114112, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED|MAP_FIXED, 4, 
> 0) = 0
> mprotect(0, 655360, PROT_NONE)          = 0
> --- SIGSEGV (Segmentation fault) @ 0 (0) ---
> +++ killed by SIGSEGV +++
>
> There is also an error just before the raw socket message about not finding 
> libc.mo file for messages in locale, but I don't think it is important. 
> Interestingly, there is such a file in my /user/share/locale/ directories in 
> many languages, including en_GB, but not in plain en.
>
> I think the problem is with the mmap, mprotect stuff.
>
> I hope this helps the developers.
>
> Janos
>
>
> On 04/21/2014 04:19 PM, Frantisek Hanzlik wrote:
>> Hi Janos, this reminded me of something similar that I have met cca three 
>> years ago. You can try to find my thread "same distro, svn1999 DOSEMU 
>> crashes on some PCs on SEGV, on others run fine" from 12/13/2010 in 
>> dosemu-users list - this was on Fedora 14, but this may be same problem 
>> which you see now on Fedora 3. But something better - I managed to compile 
>> almost last dosemu devel version on Fedora 3 i686, and this work well at me 
>> machine, both in console and under X (also both in terminal mode 'dosemu 
>> -t' and with native X (xdosemu). Because there was lots things corrected 
>> and improved, maybe it will run on Your system too. There is only one 
>> particularity: after installing RPM and first dosemu run must be copied 
>> kernel.sys to C:\ drive: cp /usr/share/dosemu/drive_z/kernel.sys 
>> ~/.dosemu/drives/c/ You can download RPM and SRPM package at: 
>> http://www.hanzlici.cz/packages/fedora/dosemu/fc3/dosemu-1.4.0.8-git621.g431face.3.dbgemu.fc3.i686.rpm 
>> http://www.hanzlici.cz/packages/fedora/dosemu/fc3/dosemu-1.4.0.8-git621.g431face.3.dbgemu.fc3.src.rpm 
>> Good luck, Franta Hanzlik 
>
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