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# Copyright 2022-2024 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 was introduced to reproduce a specific bug in GDBserver, where
# attaching an inferior while another one was running would trigger a segfault
# in GDBserver. Reproducing the bug required specific circumstances:
#
# - The first process must be far enough to have loaded its libc or
# libpthread (whatever triggers the loading of libthread_db), such that
# its proc->priv->thread_db is not nullptr
#
# - However, its lwp must still be in the `!lwp->thread_known` state,
# meaning GDBserver hasn't asked libthread_db to compute the thread
# handle yet. That means, GDB must not have refreshed the thread list
# yet, since that would cause the thread handles to be computed. That
# means, no stopping on a breakpoint, since that causes a thread list
# update. That's why the first inferior needs to be started with "run
# &".
#
# - Attaching the second process would segfault GDBserver.
#
# All of this to say, if modifying this test, please keep in mind the original
# intent.
standard_testfile
require !use_gdb_stub
if { [build_executable "failed to prepare" ${testfile} ${srcfile}] } {
return
}
proc do_test {} {
save_vars { ::GDBFLAGS } {
append ::GDBFLAGS " -ex \"maint set target-non-stop on\""
clean_restart $::binfile
}
gdb_test -no-prompt-anchor "run &"
gdb_test "add-inferior" "Added inferior 2 on connection 1 .*"
gdb_test "inferior 2" "Switching to inferior 2 .*"
set spawn_id [spawn_wait_for_attach $::binfile]
set pid [spawn_id_get_pid $spawn_id]
# This call would crash GDBserver.
gdb_attach $pid
# Read a variable from the inferior, just to make sure the attach worked
# fine.
gdb_test "print global_var" " = 123"
}
do_test
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