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

On Tue, Aug 22, 2017 at 03:34:49PM +0300, Konstantin Belousov wrote:
> ...
> $ gdb /bin/sh sh.core
> (gdb) bt
> (gdb) info registers
> (gdb) disassemble

[New LWP 100182]
Core was generated by `sh -c cc --version || echo 0.0.0'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000800b6ee08 in ?? () from /lib/libc.so.7
(gdb) bt
#0  0x0000000800b6ee08 in ?? () from /lib/libc.so.7
#1  0x0000000800b6eda1 in malloc () from /lib/libc.so.7
#2  0x00000000004116cd in ?? ()
#3  0x000000000041193f in ?? ()
#4  0x0000000000407751 in ?? ()
#5  0x00000000004074ef in ?? ()
#6  0x000000000040fb50 in ?? ()
#7  0x0000000000406892 in ?? ()
#8  0x00000000004054aa in ?? ()
#9  0x0000000000405704 in ?? ()
#10 0x000000000040515b in ?? ()
#11 0x00000000004111ae in ?? ()
#12 0x0000000000402ecf in ?? ()
#13 0x000000080064b000 in ?? ()
#14 0x0000000000000000 in ?? ()
(gdb) info registers
rax            0x800e60fa0      34374815648
rbx            0x6278c0 6453440
rcx            0x400    1024
rdx            0x5a5a5a5a5aff9c9c       6510615555437730972
rsi            0x7fffffffdf30   140737488346928
rdi            0x7fffffffdf60   140737488346976
rbp            0x7fffffffdf20   0x7fffffffdf20
rsp            0x7fffffffdea0   0x7fffffffdea0
r8             0xfefefefefefefeff       -72340172838076673
r9             0x8080808080808080       -9187201950435737472
r10            0x8006cc000      34366865408
r11            0x8006cc000      34366865408
r12            0x6278c0 6453440
r13            0x8006cc240      34366865984
r14            0x1f8    504
r15            0x7fffffffdf30   140737488346928
rip            0x800b6ee08      0x800b6ee08
eflags         0x10246  [ PF ZF IF RF ]
cs             0x43     67
ss             0x3b     59
ds             <unavailable>
es             <unavailable>
fs             <unavailable>
gs             <unavailable>
fs_base        <unavailable>
gs_base        <unavailable>
(gdb) disassemble 0x800b6ee08,0x800b6ee08
Dump of assembler code from 0x800b6ee08 to 0x800b6ee08:
End of assembler dump.
(gdb) disassemble 0x800b6ee08
No function contains specified address.
(gdb) 

> ...
> > I grabbed a copy of the dmesg.boot for today, and have attached
> > "head -100" from it to this message.
> Thank you.

:-}

> ...
> > > Does system boot into multiuser ?
> > 
> > Yes; it does.  But checking /var/log/messages, I see:
> 
> 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. :-}

But yes: once we resolve the "working /bin/sh" issue, clearing
/usr/obj & rebuilding is straighforward and shouldn't take too long.

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.