Hi,


lvs --unbuffered in Jessie seems to be broken:

sh# ulimit -c $((1024*1024))
sh# lvs vm --select 'lv_name =~ .*img' --unbuffered || echo $?
  LV       VG   Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  test.img vm   -wi-a----- 8.00g
  deb-installer.img vm   -wi-ao---- 8.00g
Segmentation fault (core dumped)
139
sh# gdb -q lvs core
Reading symbols from lvs...(no debugging symbols found)...done.

warning: core file may not match specified executable file.
[New LWP 23047]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `lvs vm --select lv_name =~ .*img --unbuffered'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007ff74c9a9ab8 in dm_bit_and () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
(gdb) bt
#0  0x00007ff74c9a9ab8 in dm_bit_and () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#1  0x00007ff74c9cf18c in ?? () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#2  0x00007ff74c9cf3a2 in ?? () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#3  0x00007ff74c9d00a2 in dm_regex_match () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#4  0x00007ff74c9c5111 in ?? () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#5  0x00007ff74c9c4ed7 in ?? () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#6  0x00007ff74c9ca2f4 in dm_report_object () from /lib/x86_64-linux-gnu/libdevmapper.so.1.02.1
#7  0x00007ff74d4e0ee9 in report_object ()
#8  0x00007ff74d467e82 in ?? ()
#9  0x00007ff74d469a95 in process_each_lv_in_vg ()
#10 0x00007ff74d46b494 in process_each_lv ()
#11 0x00007ff74d468507 in ?? ()
#12 0x00007ff74d45f258 in lvm_run_command ()
#13 0x00007ff74d45f8ee in lvm2_main ()
#14 0x00007ff74c3d9b45 in __libc_start_main (main=0x7ff74d44a6f0 <main>, argc=5, argv=0x7ffe27eeee08, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7ffe27eeedf8) at libc-start.c:287
#15 0x00007ff74d44a71e in _start ()
(gdb) q
sh#

I'm  pretty  sure  that  the  issue is related to the regex expansion, since a
fixed string comparision ('=') works fine:

sh# lvs vm --select 'lv_name = test.img' --unbuffered || echo $?
  LV       VG   Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  test.img vm   -wi-a----- 8.00g
sh#

Also,  the  output  does  always  consist of two lines plus header, before the
segfault occurs. I can confirm this on another host.

It  is  important to have at least four LVs inside a VG, this will trigger the
segfault.  Having  exactly  three  LVs  does  not segfault, but causes _wrong_
output (the last entry does not get displayed).

Please tell me if/how I can help to further debug this issue.


Cheers,

	Julius

1) People need to see the complete debug output from the failing command with
-vvvv added.  That is what enables people to reproduce issues.

2) There have been a lot of changes to the reporting code since that release,
so the first thing is to try a recent release to see if the bug is already
fixed upstream.

Alasdair

I think this is fixed already with this upstream patch (appeared in lvm2
v2.02.115):

https://git.fedorahosted.org/cgit/lvm2.git/commit/?id=f94f8463b0d3dddaa0e429123aba673d106f783e

Peter

--[ Alasdair G Kergon <agk@redhat.com> 2015-07-04 10:35:16 +0200 ]


While  I  generally  agree  to  your  hint,  lvm2 in particular seems to be as
version  2.02.111-2.2  in  all  of  stable,  testing  and unstable. Since both
libdevmapper*  and  the  binary lvm2 administration tools should have the same
version in testing/unstable, I decided not to upgrade and test again.


Cheers,

	Julius

--[ Peter Rajnoha <prajnoha@redhat.com> 2015-07-04 10:58:44 +0200 ]

This  looks  very  much like the behaviour I see. I didn't test the patch yet,
though.


Of  course I failed to attach the log, but it seems rather pointless since the
bug got confirmed and patched elsewhere.

Thanks for the quick reply to both of you!


Cheers,

	Julius