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| 1 | +# Copyright 2022 Free Software Foundation, Inc. |
| 2 | + |
| 3 | +# This program is free software; you can redistribute it and/or modify |
| 4 | +# it under the terms of the GNU General Public License as published by |
| 5 | +# the Free Software Foundation; either version 3 of the License, or |
| 6 | +# (at your option) any later version. |
| 7 | +# |
| 8 | +# This program is distributed in the hope that it will be useful, |
| 9 | +# but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | +# GNU General Public License for more details. |
| 12 | +# |
| 13 | +# You should have received a copy of the GNU General Public License |
| 14 | +# along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 15 | + |
| 16 | +# This test was introduced to reproduce a specific bug in GDBserver, where |
| 17 | +# attaching an inferior while another one was running would trigger a segfault |
| 18 | +# in GDBserver. Reproducing the bug required specific circumstances: |
| 19 | +# |
| 20 | +# - The first process must be far enough to have loaded its libc or |
| 21 | +# libpthread (whatever triggers the loading of libthread_db), such that |
| 22 | +# its proc->priv->thread_db is not nullptr |
| 23 | +# |
| 24 | +# - However, its lwp must still be in the `!lwp->thread_known` state, |
| 25 | +# meaning GDBserver hasn't asked libthread_db to compute the thread |
| 26 | +# handle yet. That means, GDB must not have refreshed the thread list |
| 27 | +# yet, since that would cause the thread handles to be computed. That |
| 28 | +# means, no stopping on a breakpoint, since that causes a thread list |
| 29 | +# update. That's why the first inferior needs to be started with "run |
| 30 | +# &". |
| 31 | +# |
| 32 | +# - Attaching the second process would segfault GDBserver. |
| 33 | +# |
| 34 | +# All of this to say, if modifying this test, please keep in mind the original |
| 35 | +# intent. |
| 36 | + |
| 37 | +standard_testfile |
| 38 | + |
| 39 | +if [use_gdb_stub] { |
| 40 | + unsupported "test requires running" |
| 41 | + return |
| 42 | +} |
| 43 | + |
| 44 | +if { [build_executable "failed to prepare" ${testfile} ${srcfile}] } { |
| 45 | + return |
| 46 | +} |
| 47 | + |
| 48 | +proc do_test {} { |
| 49 | + save_vars { $::GDBFLAGS } { |
| 50 | + append ::GDBFLAGS " -ex \"maint set target-non-stop on\"" |
| 51 | + clean_restart $::binfile |
| 52 | + } |
| 53 | + |
| 54 | + gdb_test -no-prompt-anchor "run &" |
| 55 | + gdb_test "add-inferior" "Added inferior 2 on connection 1 .*" |
| 56 | + gdb_test "inferior 2" "Switching to inferior 2 .*" |
| 57 | + |
| 58 | + set spawn_id [spawn_wait_for_attach $::binfile] |
| 59 | + set pid [spawn_id_get_pid $spawn_id] |
| 60 | + |
| 61 | + # This call would crash GDBserver. |
| 62 | + gdb_attach $pid |
| 63 | + |
| 64 | + # Read a variable from the inferior, just to make sure the attach worked |
| 65 | + # fine. |
| 66 | + gdb_test "print global_var" " = 123" |
| 67 | +} |
| 68 | + |
| 69 | +do_test |
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