[Bug cli/29223] New: gdb crashes with empty guile command in configuration file

[Bug cli/29223] New: gdb crashes with empty guile command in configuration file

[nchatz314 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

            Bug ID: 29223
           Summary: gdb crashes with empty guile command in configuration
                    file
           Product: gdb
           Version: HEAD
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: cli
          Assignee: unassigned at sourceware dot org
          Reporter: nchatz314 at gmail dot com
  Target Milestone: ---

If I create a configuration file with contents

    guile

and run gdb, it crashes. I'm trying to debug this to submit a patch, but in the
meantime I would like to at least submit this bug report, as gdb itself
instructs me to do so:

Fatal signal: Segmentation fault
----- Backtrace -----
0x55baf3e21e3f ???
0x55baf3f35928 ???
0x55baf3f35ae6 ???
0x7f2915ebda6f ???
0x55baf42282c4 ???
0x55baf3e69d3d ???
0x55baf3f76439 ???
0x55baf3e59074 ???
0x55baf41f25b7 ???
0x55baf3f35dac ???
0x55baf41efcfe ???
0x55baf3e68dce ???
0x55baf3e57f2a ???
0x55baf400e5b1 ???
0x55baf4010c2c ???
0x55baf401113e ???
0x55baf3d4fe6d ???
0x7f2915ea854f ???
0x7f2915ea8608 ???
0x55baf3d58744 ???
0xffffffffffffffff ???
---------------------
A fatal error internal to GDB has been detected, further
debugging is not possible.  GDB will now terminate.

This is a bug, please report it.  For instructions, see:
<https://www.gnu.org/software/gdb/bugs/>.

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[Bug cli/29223] gdb crashes with empty guile command in configuration file

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at sourceware dot org

--- Comment #1 from Tom Tromey <tromey at sourceware dot org> ---
I couldn't reproduce this with git master or gdb 11.
I tried:

murgatroyd. cd /tmp
murgatroyd. echo guile > .gdbinit
murgatroyd. ~/gdb/install/bin/gdb -iex 'add-auto-load-safe-path /tmp/.gdbinit'

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[Bug cli/29223] gdb crashes with empty guile command in configuration file

[nchatz314 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

--- Comment #2 from Nikolaos Chatzikonstantinou <nchatz314 at gmail dot com> ---
(In reply to Tom Tromey from comment #1)
> I couldn't reproduce this with git master or gdb 11.
> I tried:
> 
> murgatroyd. cd /tmp
> murgatroyd. echo guile > .gdbinit
> murgatroyd. ~/gdb/install/bin/gdb -iex 'add-auto-load-safe-path
> /tmp/.gdbinit'

Is the `add-auto-load-safe-path` used correctly? Doesn't seem to load anything
for me. E.g. if the file only contains `set startup-quietly on`, the splash
still shows.

The way I obtain the crash is by

    echo guile > ~/.config/gdb/gdbearlyinit

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[Bug cli/29223] gdb crashes with empty guile command in configuration file

[nchatz314 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

--- Comment #3 from Nikolaos Chatzikonstantinou <nchatz314 at gmail dot com> ---
I've narrowed it down to a null dereference of ui_out->current_uiout, here is a
backtrace:

#0  ui_out::is_mi_like_p (this=0x0) at ui-out.c:820
#1  0x00000000004fdeba in execute_control_command (cmd=0xe7b640, from_tty=0) at
cli/cli-script.c:699
#2  0x00000000005f9ee3 in guile_command (arg=<optimized out>,
from_tty=<optimized out>) at /usr/include/c++/12/bits/shared_ptr_base.h:1665
#3  0x00000000004f2d55 in cmd_func (cmd=<optimized out>, args=<optimized out>,
from_tty=<optimized out>) at cli/cli-decode.c:2514
#4  0x00000000007c7aeb in execute_command (p=<optimized out>, p@entry=0xe86ad0
"guile", from_tty=0) at top.c:699
#5  0x00000000005c053d in command_handler (command=0xe86ad0 "guile") at
event-top.c:598
#6  0x00000000007c894f in read_command_file (stream=stream@entry=0xd9b5d0) at
top.c:468
#7  0x00000000004fc088 in script_from_file (stream=stream@entry=0xd9b5d0,
file=file@entry=0xe86aa0 "/home/fox/.config/gdb/gdbearlyinit") at
cli/cli-script.c:1625
#8  0x00000000004efcab in source_script_from_stream (file_to_open=0xe86af0
"/home/fox/.config/gdb/gdbearlyinit", file=0xe86aa0
"/home/fox/.config/gdb/gdbearlyinit", stream=0xd9b5d0) at cli/cli-cmds.c:715
#9  source_script_with_search (file=0xe86aa0
"/home/fox/.config/gdb/gdbearlyinit", file@entry=<error reading variable: value
has been optimized out>, from_tty=<error reading variable: value has been
optimized out>, 
    search_path=<error reading variable: value has been optimized out>) at
cli/cli-cmds.c:760
#10 0x000000000066f652 in catch_command_errors (command=<optimized out>,
arg=<optimized out>, from_tty=<optimized out>, do_bp_actions=<optimized out>)
at main.c:515
#11 0x0000000000671ba1 in captured_main_1 (context=<optimized out>) at
/usr/include/c++/12/bits/basic_string.h:234
#12 0x0000000000671feb in captured_main (data=data@entry=0x7fffffffdd70) at
main.c:1325
#13 gdb_main (args=args@entry=0x7fffffffdda0) at main.c:1350
#14 0x0000000000432d25 in main (argc=<optimized out>, argv=<optimized out>) at
gdb.c:32

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[Bug cli/29223] gdb crashes with empty guile command in configuration file

[nchatz314 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

--- Comment #4 from Nikolaos Chatzikonstantinou <nchatz314 at gmail dot com> ---
I have just realized the error is a bit more nuanced:

The crash occurs with GNU gdb (GDB) Fedora 12.1-1.fc36, which is configured
with --with-guile and it also occurs for HEAD configured with --without-guile.

I don't seem to be able to get gdb working with --with-guile. It compiles but
I'm greeted with

Exception caught while booting Guile.
Error in function "make_objcode_from_file":
bad header on object file:
"\x7fELF\x02\x01\x01ÿ\x00\x00\x00\x00\x00\x00\x00\x00"
./gdb/gdb: warning: Could not complete Guile gdb module initialization from:
/usr/share/gdb/guile/gdb/boot.scm.
Limited Guile support is available.
Suggest passing --data-directory=/path/to/gdb/data-directory.
GNU gdb (GDB) 13.0.50.20220602-git

Apologies for the unorganized bug report, I haven't done many bug reports.

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[Bug cli/29223] gdb crashes with empty guile command in configuration file

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29223

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-06-04
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #5 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Nikolaos Chatzikonstantinou from comment #2)

> Is the `add-auto-load-safe-path` used correctly? Doesn't seem to load
> anything
> for me. E.g. if the file only contains `set startup-quietly on`, the splash
> still shows.

I think 'startup-quietly' takes effect too late in this case.

> 
> The way I obtain the crash is by
> 
>     echo guile > ~/.config/gdb/gdbearlyinit

I can reproduce it this way, thank you.

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