gdb: Fix assert for extended-remote target (PR gdb/18050)

Consider the following GDB session:

   (gdb) target extended-remote :2347
   (gdb) file /path/to/exe
   (gdb) set remote exec-file /path/to/exe
   (gdb) set detach-on-fork off
   (gdb) break breakpt
   (gdb) run
   # ... hits breakpoint
   (gdb) info inferiors
     Num  Description       Executable
   * 1    process 17001     /path/to/exe
     2    process 17002     /path/to/exe
   (gdb) kill
   (gdb) info inferiors
     Num  Description       Executable
   * 1    <null>            /path/to/exe
     2    process 17002     /path/to/exe
   (gdb) target extended-remote :2348
   ../../src/gdb/thread.c:660: internal-error: thread_info* any_thread_of_process(int): Assertion `pid != 0' failed.
   A problem internal to GDB has been detected,
   further debugging may prove unreliable.

Or, from bug PR gdb/18050:

   (gdb) start
   (gdb) add-inferior -exec /path/to/exe
   (gdb) target extended-remote :2347
   ../../src/gdb/thread.c:660: internal-error: thread_info* any_thread_of_process(int): Assertion `pid != 0' failed.
   A problem internal to GDB has been detected,
   further debugging may prove unreliable.

The issue is calling target.c:dispose_inferior with a killed inferior in
the inferior list.  This assertion is fixed in this commit.

The new test for this issue only runs on platforms that support
'detach-on-fork', and when using
'--target_board=native-extended-gdbserver'.

gdb/ChangeLog:

	PR gdb/18050:
	* target.c (dispose_inferior): Don't dispose of inferiors that are
	already killed.

gdb/testsuite/ChangeLog:

	PR gdb/18050:
	* gdb.server/extended-remote-restart.c: New file.
	* gdb.server/extended-remote-restart.exp: New file.
This commit is contained in:
Andrew Burgess 2018-06-22 20:39:26 +01:00
parent ff36536c92
commit 9d4a934ce6
5 changed files with 210 additions and 0 deletions

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@ -1,3 +1,9 @@
2018-08-08 Andrew Burgess <andrew.burgess@embecosm.com>
PR gdb/18050:
* target.c (dispose_inferior): Don't dispose of inferiors that are
already killed.
2018-08-08 Szabolcs Nagy <szabolcs.nagy@arm.com> 2018-08-08 Szabolcs Nagy <szabolcs.nagy@arm.com>
* remote.c (remote_target::download_tracepoint): Change char* to * remote.c (remote_target::download_tracepoint): Change char* to

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@ -2022,6 +2022,12 @@ target_pre_inferior (int from_tty)
static int static int
dispose_inferior (struct inferior *inf, void *args) dispose_inferior (struct inferior *inf, void *args)
{ {
/* Not all killed inferiors can, or will ever be, removed from the
inferior list. Killed inferiors clearly don't need to be killed
again, so, we're done. */
if (inf->pid == 0)
return 0;
thread_info *thread = any_thread_of_inferior (inf); thread_info *thread = any_thread_of_inferior (inf);
if (thread != NULL) if (thread != NULL)
{ {

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@ -1,3 +1,9 @@
2018-08-08 Andrew Burgess <andrew.burgess@embecosm.com>
PR gdb/18050:
* gdb.server/extended-remote-restart.c: New file.
* gdb.server/extended-remote-restart.exp: New file.
2018-08-07 Simon Marchi <simon.marchi@polymtl.ca> 2018-08-07 Simon Marchi <simon.marchi@polymtl.ca>
* gdb.fortran/nested-funcs.exp: Replace "set index = 42" with * gdb.fortran/nested-funcs.exp: Replace "set index = 42" with

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@ -0,0 +1,60 @@
/* This testcase is part of GDB, the GNU debugger.
Copyright 2018 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <stdlib.h>
static void
breakpt ()
{
asm ("" ::: "memory");
}
static void
go_child ()
{
breakpt ();
while (1)
sleep (1);
}
static void
go_parent ()
{
breakpt ();
while (1)
sleep (1);
}
int
main ()
{
pid_t pid;
pid = fork ();
if (pid == -1)
abort ();
if (pid == 0)
go_child ();
else
go_parent ();
exit (EXIT_SUCCESS);
}

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@ -0,0 +1,132 @@
# Copyright 2018 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This test is about restarting execution of a forked application when
# using gdb extended remote target.
#
# There are two issues that the test tries to expose in GDB:
#
# 1. GDB would throw an assertion upon reconnecting to a remote target
# if there was more than one inferior already active in GDB, and
#
# 2. GDB would not prune transient inferiors from the inferior list
# when reconnecting to a remote target. So, for example, an inferior
# created by GDB to track the child of a fork would usually be removed
# from the inferior list once the child exited. However, reconnecting
# to a remote target would result in the child inferior remaining in
# the inferior list.
# This test is only for extended remote targets.
if {[target_info gdb_protocol] != "extended-remote"} {
continue
}
# This test also makes use of 'detach-on-fork' which is not supported
# on all platforms.
if { ![istarget "*-*-linux*"] && ![istarget "*-*-openbsd*"] } then {
continue
}
# And we need to be able to reconnect to gdbserver.
set gdbserver_reconnect_p 1
if { [info proc gdb_reconnect] == "" } {
return 0
}
standard_testfile
if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
return -1
}
# Core of the test. DO_KILL_P controls whether we kill one of the
# inferiors before reconnecting. And FOLLOW_CHILD_P controls whether
# we follow the child or the parent at the fork.
proc test_reload { do_kill_p follow_child_p } {
global decimal
global binfile
clean_restart ${binfile}
if ![runto_main] then {
fail "can't run to main"
return 0
}
# Set detach-on-fork off
gdb_test_no_output "set detach-on-fork off"
set live_inf_ptn "process $decimal"
set dead_inf_ptn "<null>"
if ${follow_child_p} {
gdb_test_no_output "set follow-fork child"
set parent_prefix " "
set child_prefix "\\*"
set parent_inf_after_kill_ptn ${live_inf_ptn}
set child_inf_after_kill_ptn ${dead_inf_ptn}
} else {
gdb_test_no_output "set follow-fork parent"
set parent_prefix "\\*"
set child_prefix " "
set parent_inf_after_kill_ptn ${dead_inf_ptn}
set child_inf_after_kill_ptn ${live_inf_ptn}
}
gdb_breakpoint "breakpt"
gdb_continue_to_breakpoint "breakpt"
# Check we have the expected inferiors.
gdb_test "info inferiors" \
[multi_line \
" Num Description Executable.*" \
"${parent_prefix} 1 +${live_inf_ptn} \[^\r\n\]+" \
"${child_prefix} 2 +${live_inf_ptn} \[^\r\n\]+" ] \
"Check inferiors at breakpoint"
if { $do_kill_p } {
# (Optional) Kill one of the inferiors.
gdb_test "kill" \
"" \
"Kill inferior" \
"Kill the program being debugged.*y or n. $" \
"y"
# Check the first inferior really did die.
gdb_test "info inferiors" \
[multi_line \
" Num Description Executable.*" \
"${parent_prefix} 1 +${parent_inf_after_kill_ptn} \[^\r\n\]+" \
"${child_prefix} 2 +${child_inf_after_kill_ptn} \[^\r\n\]+" ] \
"Check inferior was killed"
}
# Reconnect to the target.
if { [gdb_reconnect] == 0 } {
pass "reconnect after fork"
} else {
fail "reconnect after fork"
}
}
# Run all combinations of the test.
foreach do_kill_p [list 1 0] {
foreach follow_child_p [list 1 0] {
with_test_prefix \
"kill: ${do_kill_p}, follow-child ${follow_child_p}" {
test_reload ${do_kill_p} ${follow_child_p}
}
}
}