Re: [bug-bash] Named fifo's causing hanging bash scripts

[Chet Ramey]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 1/13/15 4:29 AM, Dr. Werner Fink wrote:

>>> Bash Version: 4.3
>>> Patch Level: 33
>>> Release Status: release
>>>
>>> Description:
>>>         Named fifo's causing hanging bash scripts like
>>>
>>>         while IFS="|" read a b c ; do
>>>           [shell code]
>>>         done < <(shell code)
>>>
>>>         can cause random hangs of the bash.    An strace shows that the bash
>>>         stays in wait4()
>>
>> And when you attach to one of the hanging bash processes using gdb, what
>> does the stack traceback look like?
> 
> Yes (and sorry for the wrong email address as this was done on a clean 
> virtual sysstem)
> 
> there are two hanging bash processes together with the find command:
> 
> werner   19062  0.8  0.0  11864  2868 ttyS0    S+   10:21   0:00 bash -x 
> /tmp/brp-25-symlink
> werner   19063  0.0  0.0  11860  1920 ttyS0    S+   10:21   0:00 bash -x 
> /tmp/brp-25-symlink
> werner   19064  0.2  0.0  16684  2516 ttyS0    S+   10:21   0:00 find . -type 
> l -printf %p|%h|%l n
> 
> the gdb -p 19062 and gdb -p 19063 show
> 
> (gdb) bt
> #0  0x00007f530818a65c in waitpid () from /lib64/libc.so.6
> #1  0x000000000042b233 in waitchld (block=block@entry=1, wpid=19175) at 
> jobs.c:3235
> #2  0x000000000042c6da in wait_for (pid=pid@entry=19175) at jobs.c:2496

What do ps and gdb tell you about pid 19175 (and the corresponding pid in
the call to waitchld in the other traceback)?  Running, terminated, reaped,
other?

Chet


- -- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (Darwin)

iEYEARECAAYFAlS5HqsACgkQu1hp8GTqdKuU5QCeKfuBQ4dYeU3fSjJPgtB+31Ep
YPQAoIk8aeYkJWWcghPjYONgvyrE/qy9
=duRA
-----END PGP SIGNATURE-----