internal-error: inferior* find_inferior_pid(process_stratum_target*, int): Assertion `pid != 0' failed

Maxim Blinov <[email protected]>
Newsgroups gmane.comp.gdb.devel
Message-ID <CAHXVFW=Ttoc4WaCY5xjJXZQasCSo81h1WFWZH1FrH_3GchOf5w@mail.gmail.com> 
Hi all, I have a problem running GDB in simulator mode (CGEN) for m32r and avr.

The problem in both cases seems to be to do with the following: CGEN will
set the inferior_ptid.m_pid to 42000 (hardcoded arbitrary value). However,
at some point, when I hit 'r' to run all, the "switch_to_no_thread()" function
will set "inferior_ptid = null_ptid", and at some point later GDB will crash
(see below).

Version numbers are at the bottom of email.

I can pinpoint the place at which inferior_ptid.m_pid changes from 42000 to 0,
by running avr-gdb under my workstation-gdb, like so (the "avr-gdb" and
"workstation-gdb" are my own prefixes, just to differentiate.):

shell-window-1$ avr-gdb hello
(avr-gdb)
shell-window-2$ gdb -p <the avr-gdb pid>
(workstation-gdb)
(workstation-gdb) watch inferior_ptid.m_pid
(workstation-gdb) condition 1 inferior_ptid.m_pid != 42000
(workstation-gdb) c
(avr-gdb) target sim
(avr-gdb) load
(avr-gdb) info files
Symbols from "/home/maxim/dev/ovl/avr/test-arena/hello".
Local exec file:
    `/home/maxim/dev/ovl/avr/test-arena/hello', file type elf32-avr.
    Entry point: 0x0
    0x00800100 - 0x0080010e is .data
    0x00000000 - 0x000001b4 is .text
    0x0080010e - 0x00800114 is .bss
(avr-gdb) b *0x0
(avr-gdb) r
(workstation-gdb)
Thread 1 "avr-gdb" hit Hardware watchpoint 2: inferior_ptid.m_pid

Old value = 42000
New value = 0
0x000055f3c41229e5 in switch_to_no_thread ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/thread.c:1331
1331      inferior_ptid = null_ptid;
(workstation-gdb) bt
#0  0x000055f3c41229e5 in switch_to_no_thread ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/thread.c:1331
#1  0x000055f3c3efae59 in switch_to_inferior_no_thread (inf=0x55f3c4d48240)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c:623
#2  0x000055f3c3f038c4 in commit_resume_all_targets ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infrun.c:2880
#3  0x000055f3c3f0462e in proceed (addr=0, siggnal=GDB_SIGNAL_0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infrun.c:3183
#4  0x000055f3c3ef1c78 in run_command_1 (args=0x0, from_tty=1,
    run_how=RUN_NORMAL)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infcmd.c:678
#5  0x000055f3c3ef1d45 in run_command (args=0x0, from_tty=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infcmd.c:688
#6  0x000055f3c3d59a24 in do_const_cfunc (c=0x55f3c4e24450, args=0x0,
    from_tty=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/cli/cli-decode.c:107
#7  0x000055f3c3d5cf43 in cmd_func (cmd=0x55f3c4e24450, args=0x0, from_tty=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/cli/cli-decode.c:1952
#8  0x000055f3c412a254 in execute_command (p=0x55f3c4d0da21 "", from_tty=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/top.c:653
#9  0x000055f3c3e94151 in command_handler (command=0x55f3c4d0da20 "")
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:587
#10 0x000055f3c3e945cb in command_line_handler (rl=...)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:772
#11 0x000055f3c3e938c5 in gdb_rl_callback_handler (rl=0x55f3c4edca80 "r")
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:218
#12 0x000055f3c41f9d39 in rl_callback_read_char ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./readline/readline/callback.c:281
#13 0x000055f3c3e936ed in gdb_rl_callback_read_char_wrapper_noexcept ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:176
#14 0x000055f3c3e93797 in gdb_rl_callback_read_char_wrapper (
    client_data=0x55f3c4d0d770)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:193
#15 0x000055f3c3e93fe3 in stdin_event_handler (error=0,
    client_data=0x55f3c4d0d770)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-top.c:515
#16 0x000055f3c3e91bfe in handle_file_event (file_ptr=0x55f3c4ec93c0,
    ready_mask=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:731
#17 0x000055f3c3e921c7 in gdb_wait_for_event (block=1)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:857
#18 0x000055f3c3e90fcd in gdb_do_one_event ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:346
#19 0x000055f3c3e90ff7 in start_event_loop ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:370
#20 0x000055f3c3f507b0 in captured_command_loop ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:360
#21 0x000055f3c3f520ad in captured_main (data=0x7fff597e8340)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:1203
#22 0x000055f3c3f52113 in gdb_main (args=0x7fff597e8340)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:1218
#23 0x000055f3c3c71cc3 in main (argc=2, argv=0x7fff597e8448)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/gdb.c:32
(workstation-gdb) c

...
At this point, I hit the hardware watchpoint 2 more times. I'm not sure if thats
significant, but its just the same "changed from 42000 to 0".
...

(avr-gdb)
Starting program: /home/maxim/dev/ovl/avr/test-arena/hello
/home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c:279:
internal-error: inferior* find_inferior_pid(process_stratum_target*,
int): Assertion `pid != 0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)


And thats that. I originally did this for m32r, but when that failed, I went
to avr but has exactly the same problem.


Here is the coredump backtrace for avr-gdb:

```
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007f404663d801 in __GI_abort () at abort.c:79
#2  0x000055cb48885d69 in dump_core ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/utils.c:203
#3  0x000055cb4888630e in internal_vproblem(internal_problem *, const
char *, int, const char *, typedef __va_list_tag __va_list_tag *) (
    problem=0x55cb48f27660 <internal_error_problem>,
    file=0x55cb48a85738 "/home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x55cb48a856ab "%s: Assertion `%s' failed.",
ap=0x7fff97d46a70)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/utils.c:413
#4  0x000055cb488863f3 in internal_verror (
    file=0x55cb48a85738 "/home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x55cb48a856ab "%s: Assertion `%s' failed.",
ap=0x7fff97d46a70)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/utils.c:438
#5  0x000055cb489cf758 in internal_error (
    file=0x55cb48a85738 "/home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x55cb48a856ab "%s: Assertion `%s' failed.")
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdbsupport/errors.c:55
#6  0x000055cb4860b7c3 in find_inferior_pid (targ=0x55cb48f26de0
<gdbsim_ops>, pid=0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c:279
#7  0x000055cb4860b88a in find_inferior_ptid (targ=0x55cb48f26de0 <gdbsim_ops>,
    ptid=...) at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inferior.c:293
#8  0x000055cb48831d29 in find_thread_ptid (targ=0x55cb48f26de0
<gdbsim_ops>, ptid=...)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/thread.c:527
#9  0x000055cb4861b629 in handle_inferior_event (ecs=0x7fff97d46ec0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infrun.c:5062
#10 0x000055cb48618ab9 in fetch_inferior_event (client_data=0x0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infrun.c:4002
#11 0x000055cb485fcb43 in inferior_event_handler (event_type=INF_REG_EVENT,
    client_data=0x0) at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/inf-loop.c:43
#12 0x000055cb48624b9c in infrun_async_inferior_event_handler (data=0x0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/infrun.c:9317
#13 0x000055cb485a468e in check_async_event_handlers ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:1062
#14 0x000055cb485a2f5f in gdb_do_one_event ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:325
#15 0x000055cb485a2ff7 in start_event_loop ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/event-loop.c:370
#16 0x000055cb486627b0 in captured_command_loop ()
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:360
#17 0x000055cb486640ad in captured_main (data=0x7fff97d470e0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:1203
#18 0x000055cb48664113 in gdb_main (args=0x7fff97d470e0)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/main.c:1218
#19 0x000055cb48383cc3 in main (argc=2, argv=0x7fff97d471e8)
    at /home/maxim/dev/ovl/avr/binutils-gdb/./gdb/gdb.c:32
```

And here is the coredump backtrace for m32r-unknown-elf-gdb:

```
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007f5562123801 in __GI_abort () at abort.c:79
#2  0x00005599a200c3a7 in dump_core ()
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/utils.c:203
#3  0x00005599a200c94c in internal_vproblem(internal_problem *, const
char *, int, const char *, typedef __va_list_tag __va_list_tag *) (
    problem=0x5599a2744740 <internal_error_problem>,
    file=0x5599a2280758
"/home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x5599a22806cb "%s: Assertion `%s' failed.",
ap=0x7ffc2d752ff0)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/utils.c:413
#4  0x00005599a200ca31 in internal_verror (
    file=0x5599a2280758
"/home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x5599a22806cb "%s: Assertion `%s' failed.",
ap=0x7ffc2d752ff0)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/utils.c:438
#5  0x00005599a21bf5a0 in internal_error (
    file=0x5599a2280758
"/home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inferior.c",
    line=279, fmt=0x5599a22806cb "%s: Assertion `%s' failed.")
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdbsupport/errors.c:55
#6  0x00005599a1d906a7 in find_inferior_pid (targ=0x5599a2743ec0
<gdbsim_ops>, pid=0)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inferior.c:279
#7  0x00005599a1d9076e in find_inferior_ptid (targ=0x5599a2743ec0 <gdbsim_ops>,
    ptid=...) at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inferior.c:293
#8  0x00005599a1fb8367 in find_thread_ptid (targ=0x5599a2743ec0
<gdbsim_ops>, ptid=...)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/thread.c:527
#9  0x00005599a1da050d in handle_inferior_event (ecs=0x7ffc2d753440)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/infrun.c:5062
#10 0x00005599a1d9d99d in fetch_inferior_event (client_data=0x0)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/infrun.c:4002
#11 0x00005599a1d81a27 in inferior_event_handler (event_type=INF_REG_EVENT,
    client_data=0x0) at
/home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/inf-loop.c:43
#12 0x00005599a1da9a80 in infrun_async_inferior_event_handler (data=0x0)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/infrun.c:9317
#13 0x00005599a1d29572 in check_async_event_handlers ()
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/event-loop.c:1062
#14 0x00005599a1d27e43 in gdb_do_one_event ()
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/event-loop.c:325
#15 0x00005599a1d27edb in start_event_loop ()
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/event-loop.c:370
#16 0x00005599a1de8dee in captured_command_loop ()
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/main.c:360
#17 0x00005599a1dea6eb in captured_main (data=0x7ffc2d753660)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/main.c:1203
#18 0x00005599a1dea751 in gdb_main (args=0x7ffc2d753660)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/main.c:1218
#19 0x00005599a1b0b413 in main (argc=2, argv=0x7ffc2d753768)
    at /home/maxim/dev/ovl/m32r/binutils-gdb/./gdb/gdb.c:32
```

I saw this discussion that seemed to have a very similar problem, here:
https://sourceware.org/ml/gdb-patches/2019-10/msg00512.html

The patch doesn't apply anymore, but even when I did try adding an equivalent
statement, it still didn't work (I only tried with AVR though).

Version numbers:

maxim@fujitsu:~/dev/ovl/avr/test-arena$ avr-gdb --version
GNU gdb (GDB) 10.0.50.20200201-git
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
maxim@fujitsu:~/dev/ovl/avr/test-arena$ avr-as --version
GNU assembler (GNU Binutils) 2.34
Copyright (C) 2020 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public Licence version 3 or later.
This program has absolutely no warranty.
This assembler was configured for a target of `avr'.

Maxim
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