/dev/p* causes shell crash in i686

[Brian Inglis]

On 2020-09-10 13:19, Ken Brown via Cygwin wrote:
> On 9/10/2020 3:15 PM, Andrew Schulman via Cygwin wrote:
>>> On Sep  9 08:08, Andrew Schulman via Cygwin wrote:
>>>> Here's a strange one. In bash in i686, try to run:
>>>>
>>>> ls /dev/ptmx
>>>>
>>>> I only get about as far as:
>>>>
>>>> ls /dev/p
>>>>
>>>> and then my terminal window vanishes. This happens:
>>>>
>>>> * In fish or bash.
>>>> * On two different hosts that I've tried.
>>>> * In mintty or a system terminal. In the system terminal, sometimes the
>>>> command works normally the first time, but fails the 2nd time; or I have to
>>>> press <TAB> after `ls /dev/p`, then the terminal vanishes.
>>>> * With other commands that treat their arguments as files, not text. So for
>>>> example, I can't finish typing `cat /dev/ptmx` or `test -r /dev/ptmx`
>>>> before the terminal window vanishes, but `echo /dev/ptmx` works normally.
>>>>
>>>> It doesn't happen:
>>>>
>>>> * In x86_64 - only i686.
>>>> * In scripts - only interactively.
>>>>
>>>> Is anyone else able to reproduce this? I've tried to capture an strace log,
>>>> but I've failed so far. The strace seems to stop the crash. Still trying.
>>>>
>>>> I thought this could be a BLODA problem, but the two hosts I tried are
>>>> running different virus scanners (McAfee and Windows Defender).
>>>>
>>>> Cygwin 3.1.7-1, all packages up-to-date. Output of cygcheck -svr attached.
>>>>
>>>> Andrew
>>>
>>> I think I fixed it.  I just uploaded new developer snapshots to
>>> https://cygwin.com/snapshots/  Please give them a try.
>>
>> When I substitute cygwin1-20090909.dll for cygwin1.dll in i686, I can't run
>> any commands. They all give "The application was unable to start correctly
>> (0xc0000022)". Anything different I should be doing?
> 
> Check the permissions on cygwin1-20090909.dll.  Is it executable?

I recommend untar elsewhere and mv don't cp DLLs, especially cygwin1.dlls, as
they seem to be able to get into a state showing such symptoms as above, even
with local test builds, or after downloading and stripping Alternate Data
Streams if present, tweaking perms and ACLs.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in IEC units and prefixes, physical quantities in SI.]