Re: pipe handling errors

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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On Jul 14 17:40, Nellis, Kenneth wrote:
> When running a bash pipeline using the latest 64-bit packages, 
> I occasionally get output like the following:
> 
> 1479561950 [waitproc] -bash 10000 sig_send: error sending signal 20, pipe handle 0x2710, nb 132, packsize 0, Win32 error 109
> 
> That one was the result of: strings <binary file> | grep <pattern> | sort | uniq -c
> 
> Here's a different one that I got twice when sending "strings" 
> output to "grep" and once sending "strings" output to "wc -l":
> 
> 605884587 [main] -bash 10000 sig_send: error sending signal -66, pipe handle 0x2710, nb 132, packsize 0, Win32 error 0
> 
> I haven't found them to be repeatable.
> 
> I just tried on 32-bit Cygwin and got the following twice in a row, 
> but not a third time, so I suspect a race condition.
> 
>       1 [main] -bash 9528 sig_send: error sending signal -34, pipe handle 0x2538, nb 152, packsize 0, Win32 error 0
> 25098461 [main] -bash 9528 sig_send: error sending signal -34, pipe handle 0x2538, nb 152, packsize 0, Win32 error 0
> 
> The initial "1" on the first one looks interesting. 
> This one also was: strings <binary file> | grep <pattern>
> 
> The common element in all these examples was generating the pipeline data
> with "strings". I don't recall whether strings was always involved or not.
> 
> Not a big concern because the generated output looks correct, 
> but a tad annoying. Thought it worth reporting.
> 
> FWIW, on 64-bit:
> Cygwin64> uname -a
> CYGWIN_NT-6.1 COR900GFY5 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin
> Cygwin64> cygcheck -f `which strings`
> binutils-2.24.51-4
> Cygwin64>
> 
> On 32-bit:
> Cygwin32> uname -a
> CYGWIN_NT-6.1-WOW64 COR900GFY5 1.7.30(0.272/5/3) 2014-05-23 10:36 i686 Cygwin
> Cygwin32> cygcheck -f `which strings`
> binutils-2.24.51-4
> Cygwin32>

I know that we got this message more often in the past, but I'm totally
unable to reproduce it these days.  I tried with 1.7.30 as well as the
latest snapshots.

I'm wondering if a pipe could be intercepted by a virus checker or
something like that.  Whatever it is, would you mind to give the latest
developer snapshot DLL (2014-07-15) from http://cygwin.com/snapshots/ a
try?  Chris has fixed a typo in the above debug message.  If it still
happens for you, maybe the new output helps better to find the cause.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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