Re: SIGSEGV in /bin/sh after r322740 -> r322776 update

On Tue, Aug 22, 2017 at 04:19:58PM +0300, Konstantin Belousov wrote:
> ...
> > > Ok, can you rebuild kernel and libc from scratch ?  I.e. remove your
> > > object directories.
> > 
> > I think I'll need a working /bin/sh to do that.  As noted, I could
> > try the stable/11 /bin/sh; on the other hand, if it's dying in a
> > library, that's not likely to help a whole lot. :-}
> I highly suspect that this is not /bin/sh at all.  Backtrace strongly
> suggests that the malloc() has issues, but again I suspect that the
> reason is not an issue in malloc, but its use of TLS.
> 
> The amd64 changes were to the TLS base register handling.  So you might
> try to boot previous kernel.  If this works out without replacing libc
> then it is definitely TLS, but I still do not know what is wrong.
> 
> > 
> > But yes: once we resolve the "working /bin/sh" issue, clearing
> > /usr/obj & rebuilding is straighforward and shouldn't take too long.
> ....

OK.  Booting from the previous kernel (/boot/kernel.old) allowed /bin/sh
(et al.) to work without segfaults, so after clearing /usr/obj, I
rebuilt r322776 from scratch (yes, userland as well as kernel).

On reboot, I wtached the serial console, and noted:

...
Mounting local filesystems:.
ELF ldconfig path: /lib /usr/lib /usr/lib/compat /usr/local/lib /usr/local/lib/perl5/5.24/mach/CORE
32-bit compatibility ldconfig path: /usr/lib32 /usr/lib32/compat
Setting hostname: freebeast.catwhisker.org.
Setting up harvesting: [UMA],[FS_ATIME],SWI,INTERRUPT,NET_NG,NET_ETHER,NET_TUN,MOUSE,KEYBOARD,ATTACH,CACHED
Feeding entropy: .
Starting Network: lo0 re0.
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_pIPV6>
        inet6 ::id 298 (sh), uid 0: exited on signal 11 prefixlen 128 1 (core dumped)

        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 
        inet 127.0.0.1 netmask 0xff000000 
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
        groups: lo 
re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTpICAST> metric 0 id 305 (sh), uid 0: exited on signal 11 (core dumped)
mtu 1500
        options=8209b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC,LINKSTATE>
        ether 98:90:96:d6:c9:6d
        inet 172.16.8.10 netmask 0xffffff00 pid 310 (sh), uid 0: exited on signal 11 (core dumped)
broadcast 172.16.8.255 
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (none)
        status: no re0: link state changed to UP
carrier
Segmentation fault (core dumped)
Startpid 314 (sh), uid 0: exited on signal 11 (core dumped)
ing devd.
Segmentation fault (core dumped)
Segmentation fault (core dumped)
Segmentation fault (core dumped)
pid 319 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)
pid 330 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)ubt0 on uhub2
ubt0: <Broadcom Corp BCM43142A0, rev 2.00/1.12, addr 3> on usbus0

random: harvesting attach, 8 bytes (4 bits) from ubt0
pid 339 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)
pid 343 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)WARNING: attempt to domain_add(bluetooth) after domainfinalize()

WARNING: attempt to domain_add(netgraph) after domainfinalize()
add host 127.0.0.1: gateway lo0 fib 0: route already in table
add net default: gateway 172.16.8.1
add host ::1: gateway lo0 fib 0: route already in table
add net fe80::: gateway ::1
add net ff02::: gateway ::1
add net ::ffff:0.0.0.0: gateway ::1
add net ::0.0.0.0: gateway ::1
Creating and/or trimming log files.
Starting syslogd.
Starting rpcbind.
NFS access cache time=60
No core dumps found.
Setting NIS domain: lmdhw.com.
Starting ypbind.
Clearing /tmp (X related).
Starting mountd.
NFSv4 is disabled
Starting nfsd.
Starting statd.
Starting lockd.
Recovering vi editor sessions:.
Starting lpd.
Upda
FreeBSD/amd64 (freebeast.catwhisker.org) (ttyu0)

login: 
[end of console output -- dhw]


So ... looks as if we still have at least one issue, and we have a way
to evade the segfaults.

Bisection time?  Or if there's another approach (or even a suggestion
for a revision to try first), I'm up for it.  9And yes, I'll just
be rebuilding the kernel for the rest of this exercise, I think.
That should speed things up significantly.)

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
If we wish to eliminate sources of Fake News, start at the top: D. Trump.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.