Crashes in libthr?

[Konstantin Belousov]

On Sun, Mar 13, 2016 at 01:32:20PM -0500, Larry Rosenman wrote:
> On 2016-03-13 13:12, Konstantin Belousov wrote:
> > On Sun, Mar 13, 2016 at 11:16:20AM -0500, Larry Rosenman wrote:
> >> I updated one of my servers, and WHILE DOING THE INSTALLWORLD, I get
> >> segfaults.
> >> 
> >> ANY multithreaded program crashes.
> >> 
> >> I reverted libthr, and it's fine.
> >> 
> >> borg.lerctr.org / # gdb -c zfs.core /sbin/zfs
> >> GNU gdb 6.1.1 [FreeBSD]
> >> Copyright 2004 Free Software Foundation, Inc.
> >> GDB is free software, covered by the GNU General Public License, and 
> >> you
> >> are
> >> welcome to change it and/or distribute copies of it under certain
> >> conditions.
> >> Type "show copying" to see the conditions.
> >> There is absolutely no warranty for GDB.  Type "show warranty" for
> >> details.
> >> This GDB was configured as "amd64-marcel-freebsd"...
> >> Core was generated by `zfs'.
> >> Program terminated with signal 11, Segmentation fault.
> >> Reading symbols from /lib/libjail.so.1...Reading symbols from
> >> /usr/lib/debug//lib/libjail.so.1.debug...done.
> >> done.
> >> Loaded symbols for /lib/libjail.so.1
> >> Reading symbols from /lib/libnvpair.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libnvpair.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libnvpair.so.2
> >> Reading symbols from /lib/libuutil.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libuutil.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libuutil.so.2
> >> Reading symbols from /lib/libzfs_core.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libzfs_core.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libzfs_core.so.2
> >> Reading symbols from /lib/libzfs.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libzfs.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libzfs.so.2
> >> Reading symbols from /lib/libc.so.7...Reading symbols from
> >> /usr/lib/debug//lib/libc.so.7.debug...done.
> >> done.
> >> Loaded symbols for /lib/libc.so.7
> >> Reading symbols from /lib/libmd.so.6...Reading symbols from
> >> /usr/lib/debug//lib/libmd.so.6.debug...done.
> >> done.
> >> Loaded symbols for /lib/libmd.so.6
> >> Reading symbols from /lib/libumem.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libumem.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libumem.so.2
> >> Reading symbols from /lib/libutil.so.9...Reading symbols from
> >> /usr/lib/debug//lib/libutil.so.9.debug...done.
> >> done.
> >> Loaded symbols for /lib/libutil.so.9
> >> Reading symbols from /lib/libm.so.5...Reading symbols from
> >> /usr/lib/debug//lib/libm.so.5.debug...done.
> >> done.
> >> Loaded symbols for /lib/libm.so.5
> >> Reading symbols from /lib/libavl.so.2...Reading symbols from
> >> /usr/lib/debug//lib/libavl.so.2.debug...done.
> >> done.
> >> Loaded symbols for /lib/libavl.so.2
> >> Reading symbols from /lib/libbsdxml.so.4...Reading symbols from
> >> /usr/lib/debug//lib/libbsdxml.so.4.debug...done.
> >> done.
> >> Loaded symbols for /lib/libbsdxml.so.4
> >> Reading symbols from /lib/libgeom.so.5...Reading symbols from
> >> /usr/lib/debug//lib/libgeom.so.5.debug...done.
> >> done.
> >> Loaded symbols for /lib/libgeom.so.5
> >> Reading symbols from /lib/libz.so.6...Reading symbols from
> >> /usr/lib/debug//lib/libz.so.6.debug...done.
> >> done.
> >> Loaded symbols for /lib/libz.so.6
> >> Reading symbols from /lib/libthr.so.3...done.
> >> Loaded symbols for /lib/libthr.so.3
> > Why all libs have debug symbols, while your most interesting one,
> > libthr.so.3, does not ?
> > 
> >> Reading symbols from /lib/libsbuf.so.6...Reading symbols from
> >> /usr/lib/debug//lib/libsbuf.so.6.debug...done.
> >> done.
> >> Loaded symbols for /lib/libsbuf.so.6
> >> Reading symbols from /libexec/ld-elf.so.1...done.
> >> Loaded symbols for /libexec/ld-elf.so.1
> >> #0  0x0000000802703f81 in __pthread_cxa_finalize () from
> >> /lib/libthr.so.3
> >> [New LWP 100957]
> >> (gdb) bt
> >> #0  0x0000000802703f81 in __pthread_cxa_finalize () from
> >> /lib/libthr.so.3
> >> #1  0x0000000802703e85 in __pthread_cxa_finalize () from
> >> /lib/libthr.so.3
> >> #2  0x0000000802707052 in ?? () from /lib/libthr.so.3
> >> #3  0x000000080063fc00 in ?? ()
> >> #4  0x00007fffffffe638 in ?? ()
> >> #5  0x00007fffffffe5b0 in ?? ()
> >> #6  0x00000008026f8fd6 in atoi at plt () from /lib/libthr.so.3
> >> #7  0x00007fffffffe5b0 in ?? ()
> >> #8  0x000000080061adfd in r_debug_state () from /libexec/ld-elf.so.1
> >> Previous frame inner to this frame (corrupt stack?)
> >> (gdb)
> >> 
> >> old SVN: r296103
> >> new SVN: r296796M
> >> (The M is a nd6 patch from markj@)
> >> 
> >> this was a FULL buildworld/buildkernel.
> > 
> > If you cd lib/libthr and do
> > 	make clean all install DEBUG_FLAGS=-g
> > on the broken world, does it fix the problem ?  If not, do debugging
> > symbols from libthr appear accessible to gdb at least ?  Try this to
> > get useful backtrace with source lines information.
> ar crashes linking the library......

ar does not link library, it archives .o into .a archive.
That said, neither ar nor ld (I am not sure whether 'ar' or 'linking'
is a thinko in the sentence above) do not depend on libthr. You have
something more fundamental broken.

I put the libthr.so.3 built with the debugging symbols on amd64, using head
r296779, at https://people.freebsd.org/~kib/misc/libthr.so.3 .  Try with
it by manually copying the file to /lib.  If still crashing, it should
show the line numbers.