core dump with fc

core dump with fc

[Adam Spiers]

I have an alias for extracting from tar balls after looking at them
(thanks Bart :-)

xt: aliased to fc -e - tvf=xf ztf=zxf -1

However ...

$ echo tvf
$ xt
zsh: 15486 segmentation fault (core dumped)  zsh

Stack trace follows.  This /doesn't/ happen if I start up with -f, but
I'm hoping the bug is obvious enough that I won't have to narrow the
problem down to one particular line in my huge .zshrc.

#0  0x80542a3 in fcsubs (sp=0xbffff43c, sub=0x646c6f62) at builtin.c:1345
1345            oldstr = sub->name;
#1  0x805452c in fclist (f=0x80e2b20, n=0, r=0, D=0, d=0, first=3039, 
    last=3039, subs=0x40014a88, pprog=0x0) at builtin.c:1410
#2  0x805410f in bin_fc (nam=0x40014a38 "fc", argv=0xbffff4c8, 
    ops=0xbffff51c "", func=16) at builtin.c:1279
#3  0x8052047 in execbuiltin (args=0x400149e8, bn=0x80b37bc) at builtin.c:368
#4  0x8062497 in execcmd (state=0xbffff7c8, input=0, output=0, how=18, last1=2)
    at exec.c:2254
#5  0x805f18e in execpline2 (state=0xbffff7c8, pcode=323, how=18, input=0, 
    output=0, last1=0) at exec.c:1180
#6  0x805e70d in execpline (state=0xbffff7c8, slcode=8194, how=18, last1=0)
    at exec.c:973
#7  0x805e129 in execlist (state=0xbffff7c8, dont_change_job=0, exiting=0)
    at exec.c:820
#8  0x805de37 in execode (p=0x40014960, dont_change_job=0, exiting=0)
    at exec.c:726
#9  0x80725e3 in loop (toplevel=1, justonce=0) at init.c:150
#10 0x805164c in main (argc=1, argv=0xbffff874) at ./main.c:86
#11 0x4006acb3 in __libc_start_main (main=0x8051470 <main>, argc=1, 
    argv=0xbffff874, init=0x8050a00 <_init>, fini=0x80ab42c <_fini>, 
    rtld_fini=0x4000a350 <_dl_fini>, stack_end=0xbffff86c)
    at ../sysdeps/generic/libc-start.c:78

Re: core dump with fc

[Bart Schaefer]

On Apr 11,  9:38pm, Adam Spiers wrote:
>
> Stack trace follows.  This /doesn't/ happen if I start up with -f

It *does* happen to me when I start up with -f.  Essentially the same
stack trace, but that value for `sub' doesn't look very good in frame #0.
(I have zsh-mem-debug etc. turned on, so that's probably a freed-memory
pattern.)

(gdb) where
#0  0x80538db in fcsubs (sp=0xbffff714, sub=0xffffffff)
    at ../../zsh-3.1.6/Src/builtin.c:1345
#1  0x8053b01 in fclist (f=0x80ce320, n=0, r=0, D=0, d=0, first=2, last=2, 
    subs=0x400e4898, pprog=0x0) at ../../zsh-3.1.6/Src/builtin.c:1410
#2  0x8053755 in bin_fc (nam=0x400e4848 "fc", argv=0xbffff7a4, 
    ops=0xbffff804 "", func=16) at ../../zsh-3.1.6/Src/builtin.c:1279
#3  0x80516ed in execbuiltin (args=0x400e47f8, bn=0x80b1aa8)
    at ../../zsh-3.1.6/Src/builtin.c:368
#4  0x8061526 in execcmd (state=0xbffffab8, input=0, output=0, how=18, last1=2)
    at ../../zsh-3.1.6/Src/exec.c:2254
#5  0x805e327 in execpline2 (state=0xbffffab8, pcode=259, how=18, input=0, 
    output=0, last1=0) at ../../zsh-3.1.6/Src/exec.c:1180
#6  0x805d8b7 in execpline (state=0xbffffab8, slcode=8194, how=18, last1=0)
    at ../../zsh-3.1.6/Src/exec.c:973
#7  0x805d2b5 in execlist (state=0xbffffab8, dont_change_job=0, exiting=0)
    at ../../zsh-3.1.6/Src/exec.c:820
#8  0x805cfb7 in execode (p=0x400e4778, dont_change_job=0, exiting=0)
    at ../../zsh-3.1.6/Src/exec.c:726
#9  0x8070922 in loop (toplevel=1, justonce=0)
    at ../../zsh-3.1.6/Src/init.c:150
#10 0x8050ce0 in main (argc=2, argv=0xbffffb34)
    at ../../zsh-3.1.6/Src/main.c:86