-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On 1/16/15 10:25 AM, Dr. Werner Fink wrote:
> On Fri, Jan 16, 2015 at 09:09:25AM -0500, Chet Ramey wrote:
>> On 1/12/15 9:55 AM, wer...@linux-8jdz.site 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()
>>
>> I can't reproduce this. I spun up a VM running OpenSUSE 13 and ran the
>> attached script against a version of bash-4.3.33 that was modified to use
>> FIFOs instead of /dev/fd. There were no hangs in any of about 30 runs.
>
> Hmmm ... what I see is
OK, but if I can't reproduce it, I can't investigate it.
>
> werner 10920 0.0 0.0 11860 2876 pts/1 S+ 15:59 0:00 bash
> /tmp/brp-25-symlink
> werner 10921 0.0 0.0 11856 1844 pts/1 S+ 15:59 0:00 bash
> /tmp/brp-25-symlink
> werner 10922 0.0 0.0 16684 2476 pts/1 S+ 15:59 0:00 find .
> -type l -printf %p|%h|%l n
>
> d136:~ # ll /proc/10920/fd
> total 0
> lr-x------ 1 werner suse 64 Jan 16 15:59 0 -> pipe:[124428]
> lrwx------ 1 werner suse 64 Jan 16 15:59 1 -> /dev/pts/1
> lrwx------ 1 werner suse 64 Jan 16 15:59 10 -> /dev/pts/1
> lrwx------ 1 werner suse 64 Jan 16 15:59 2 -> /dev/pts/1
> lr-x------ 1 werner suse 64 Jan 16 15:59 255 -> /tmp/brp-25-symlink
> d136:~ # ll /proc/10921/fd
> total 0
> lrwx------ 1 werner suse 64 Jan 16 15:59 0 -> /dev/pts/1
> l-wx------ 1 werner suse 64 Jan 16 15:59 1 -> pipe:[124428]
> lrwx------ 1 werner suse 64 Jan 16 15:59 2 -> /dev/pts/1
>
> ... but in the build there is
>
> [ 131s] checking for mkfifo... yes
Sure, it's there, but if /dev/fd exists bash will prefer it. Since the
VM I'm testing on has /dev/fd I had to manually edit config.h to disable
it.
>
> [ 150s] execute_cmd.c: In function 'execute_command_internal':
> [ 150s] execute_cmd.c:1034:12: warning: 'ofifo_list' may be used
> uninitialized in this function [-Wmaybe-uninitialized]
> [ 150s] free ((void *)ofifo_list);
This isn't a useful warning. The `free' is only called if the saved_fifo
flag is set, and that's only set if ofifo_list is initialized.
- --
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (Darwin)
iEYEARECAAYFAlS5LscACgkQu1hp8GTqdKswzACeK333huO5pI5LF8DqiVxa/L2X
ZlYAn0DfbeUiLGB2SEA/O8E/kLer7yNW
=f4G5
-----END PGP SIGNATURE-----
