Re: Is this a bug?

[George R Goffe]

Chet,

I'm really perplexed with this situation. I type in "ls -al 123456<tab>" with 
only 1 tab key. NO indication of what's happening. I hit enter and get a 
message that "ls: cannot access '123456': No such file or directory" I try the 
same command but with 2 tab keys... hit enter and get the same msg. 

I tried the same with a partial filename that DOES exist in the directory. I 
can't seem to get the filename completion to ctrl-c out. gdb sees the ctrl-c 
but bash stays in the attempted filename completion. Enter doesn't work. Ctrl-c 
doesn't work. Ctrl-z doesn't work.

Shouldn't there be a message about no file found presented by bash? There 
appears to be NO indication that filename completion has failed to find a file.

I'm at a loss as to what to do at this point. What I would like to be able to 
ctrl-c out of filename completion.

Is this a konsole problem? I will try xterms.

What are your thoughts?

Are you able to create this situation on your system(s)?

Best regards,

George...


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Attaching to process 706812
Reading symbols from /usr/bin/bash...
Reading symbols from /usr/lib/debug/usr/bin/bash-5.0.17-2.fc33.x86_64.debug...
Reading symbols from /usr/lib64/libtinfo.so.6...
Reading symbols from 
/usr/lib/debug/usr/lib64/libtinfo.so.6.2-6.2-3.20200222.fc33.x86_64.debug...
Reading symbols from /usr/lib64/libdl.so.2...
Reading symbols from /usr/lib/debug/usr/lib64/libdl-2.32.9000.so.debug...
Reading symbols from /usr/lib64/libc.so.6...
Reading symbols from /usr/lib/debug/usr/lib64/libc-2.32.9000.so.debug...
Reading symbols from /lib64/ld-linux-x86-64.so.2...
Reading symbols from /usr/lib/debug/usr/lib64/ld-2.32.9000.so.debug...
Reading symbols from /usr/lib64/libnss_sss.so.2...
Reading symbols from 
/usr/lib/debug/usr/lib64/libnss_sss.so.2-2.3.1-4.fc33.x86_64.debug...
Reading symbols from /usr/lib64/libnss_files.so.2...
Reading symbols from /usr/lib/debug/usr/lib64/libnss_files-2.32.9000.so.debug...
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020, 
writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, timeout=<optimized 
out>, timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>) at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

(gdb) continue
Continuing.




Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.
^[[A

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb) continue
Continuing.

Program received signal SIGINT, Interrupt.
0x00007f11222f528b in __pselect (nfds=1, readfds=readfds@entry=0x7ffdafb3f020,
    writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, 
timeout=<optimized out>,
    timeout@entry=0x0, sigmask=0x7ffdafb3efe0, sigmask@entry=0x55f28c2904e0 
<_rl_orig_sigset>)
    at ../sysdeps/unix/sysv/linux/pselect.c:48
48        return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
(gdb)







On Thursday, August 20, 2020, 7:29:38 AM PDT, Chet Ramey <chet.ramey@case.edu> 
wrote: 





On 8/19/20 4:55 PM, George R Goffe wrote:
> Chet,
> 
> I tried several times to create the problem. I think I succeeded. I did 
> install the "debuginfo" files I could find but it looks like libnss_sss.so's 
> debuginfo isn't built properly? It's supplied by sssd-client. I tried 
> installing sssd-client-debuginfo but it is already installed. I don't 
> remember doing that. Sigh... Somehow libnss_sss.so is referenced by bash? 
> That's what gdb thinks.

Yep, it needs it to get access to user and group data for things like tilde
expansion.

> Anyway, I tried causing the problem. ls -al zzz<tab-key> and then ctrl-c with 
> seemingly no response. I'll have to try running gdb in another konsole so I 
> can watch what happens when I <ctrl-c>... I'll do that now. Stand by. 

The trace you sent shows readline waiting in pselect for user input, so it
must be after the directory read was interrupted.

The only thing I can suggest is to defer the attach in gdb until bash
appears frozen. That may not work, but it's better than what you got.


-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
        ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/