Re: cygwin stopped working

[Bryan Zimmer <bazthelinuxguy@gmail.com>]

I have been following this thread closely as I have a similar problem. It
only differs in that mintty, which I use to start bash, fails completely.
It tells me that it cannot fork, that the problem could be that I have more
than 1 cygwin1.dll, that I should run rebaseall or rebase --help.
Unfortunately all cygwin processes have the same problem. Even a fresh,
clean re-installation of all of cygwin left me with the same problem.



On Mon, Feb 12, 2018 at 10:58 PM, Andreas Schiffler <aschiffler@ferzkopp.net
> wrote:

> Found the workaround (read: not really a solution as it leaves the system
> vulnerable, but it unblocks cygwin)
> - Go to Windows Defender Security Center - Exploit protection settings
> - Disable System Settings - Force randomization for images (Mandatory
> ASLR) and Randomize memory allocations (Bottom-up ASLR) from "On by
> default" to "Off by default"
>
> Now setup.exe works and can rebase everything; after that Cygwin Terminal
> starts as a working shell without problems.
>
> @cygwin dev's - It seems one of the windows updates (system is on 1709
> build 16299.214) might have changed my ASLR settings to "system wide
> mandatory" (i.e. see https://blogs.technet.microsof
> t.com/srd/2017/11/21/clarifying-the-behavior-of-mandatory-aslr/ for info)
> so that the cygwin DLLs don't work correctly anymore (i.e. see old thread
> about this topic here https://www.cygwin.com/ml/cygw
> in/2013-06/msg00092.html). This change might have made it into the system
> as part of the security update for Meltdown+Spectre (I am speculating), but
> that could explain why my cygwin installation that worked fine before (i.e.
> mid-2017) stopped working suddenly (beginning 2018). It would be good to
> device a test for the setup.exe that checks the registry (likely
> [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session
> Manager\kernel]) for this state and alerts the user.
> @jostein - rebase as part of setup.exe had failed as well (see above).
> @Achim - that didn't work or do anything (see above).
>
>
> On 2/12/2018 8:49 AM, Jostein Berntsen wrote:
>
>> On 11.02.18,17:16, Andreas Schiffler wrote:
>>
>>> Thanks for the tip, but that didn't seem to have helped.
>>>
>>> The registry setting CYGWIN_NOWINPATH=1 did not seem to affect the
>>> environment as seen in bash.
>>>
>>> The variable seems to be set:
>>>
>>> bash-4.4$ set
>>> ...snip...
>>> COMSPEC='C:\WINDOWS\system32\cmd.exe'
>>> CYGWIN_NOWINPATH=1
>>> ...snip
>>>
>>> but the path variable contains still all the common system locations:
>>>
>>> bash-4.4$ echo $PATH
>>> /cygdrive/c/ProgramData/Oracle/Java/javapath:/cygdrive/c/Program Files
>>> (x86)/iis express/PHP/v5.3:/cygdrive/c/Program Files/Common Files/Mic
>>> rosoft Shared/Windows Live:/cygdrive/c/Program Files (x86)/Common
>>> Files/Microsoft Shared/Windows Live:/cygdrive/c/Program Files
>>> (x86)/Intel/
>>> iCLS Client:/cygdrive/c/Program Files/Intel/iCLS
>>> Client:/cygdrive/c/Windows/system32:/cygdrive/c/Windows:...snip...
>>>
>>> Manually overriding the PATH variable in bash did not help (presumably
>>> because the offending DLL is already loaded):
>>>
>>> bash-4.4$ export PATH=/usr/local/bin:/usr/bin:/bin
>>> bash-4.4$ echo $PATH
>>> /usr/local/bin:/usr/bin:/bin
>>> bash-4.4$
>>> bash-4.4$
>>> bash-4.4$ ls
>>>        0 [main] bash (11276) C:\Cygwin\bin\bash.exe: *** fatal error -
>>> cygheap base mismatch detected - 0x3C52410/0x36F2410.
>>> This problem is probably due to using incompatible versions of the cygwin
>>> DLL.
>>> Search for cygwin1.dll using the Windows Start->Find/Search facility
>>> and delete all but the most recent version.  The most recent version
>>> *should*
>>> reside in x:\cygwin\bin, where 'x' is the drive on which you have
>>> installed the cygwin distribution.  Rebooting is also suggested if you
>>> are unable to find another cygwin DLL.
>>>
>>>
>>> On 2/11/2018 2:42 AM, Doug Henderson wrote:
>>>
>>>> On 11 February 2018 at 01:18, Andreas Schiffler  wrote:
>>>>
>>>>> Terminal (bash) fails with:
>>>>>
>>>>> Error: Could not fork child process: Resource temporarily unavailable
>>>>> (-1).
>>>>> DLL rebasing may be required; see 'rebaseall / rebase --help'.
>>>>>
>>>>> {snip}
>>>>
>>>>> bash-4.4$ ls
>>>>>         1 [main] bash (6316) C:\Cygwin\bin\bash.exe: *** fatal error -
>>>>> cygheap
>>>>> base mismatch detected - 0x3922410/0x3962410.
>>>>> This problem is probably due to using incompatible versions of the
>>>>> cygwin
>>>>> DLL.
>>>>>
>>>> {snip}
>>>>
>>>>> I do have another version of the cygwin dll file on the system (Plex
>>>>> installation) but that never caused any issues in the past.
>>>>>
>>>> {snip}
>>>>
>>>> Run setup.exe for Cugwin once again and let it rebase. Then reboot and
>> see if that works.
>>
>> Jostein
>>
>>
>>
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