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# Copyright 2021-2024 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/>.
# Test detaching from a process that is running and has threads
# constantly hitting a breakpoint and stepping over it, in all
# combinations of:
#
# - maint target non-stop off/on
# - set non-stop on/off
# - displaced stepping on/off
#
# This stresses the edge cases of detaching while a displaced step or
# an in-line step over are in progress.
#
# A fail mode is that the inferior process dies after being detached.
# This can happen because e.g.:
#
# - GDB leaves a breakpoint installed behind, or
#
# - GDB leaves a thread running in the displaced step scratch buffer.
# With no debugger around to run the finish step, the thread runs
# off of the scratch buffer, with undefined results.
#
# To exercise this, the testcase reattaches to the process shortly
# after detaching, ensuring the process is still alive and well.
#
# In addition, since GDB may pause threads of all processes for
# stepping over a breakpoint, it needs to re-resume all threads if it
# detaches from the process that was just stepping over the
# breakpoint. To ensure that, the testcase actually runs a second
# process at the same time as the one that is used to test detaching.
# After the first process is detached, the testcase sends a SIGUSR1 to
# the second process. If threads failed to be resumed, then the
# SIGUSR1 is never reported to the user, resulting in timeout. The
# threads of this second process will also be constantly stepping over
# a breakpoint, which has helped with exposing further corner case
# bugs.
require can_spawn_for_attach
standard_testfile
set bp_lineno [gdb_get_line_number "Set breakpoint here"]
# Number of threads started by the program.
set n_threads 10
# Start GDB, configuring various settings according to the arguments.
proc start_gdb_for_test {condition_eval target_non_stop non_stop displaced} {
save_vars { ::GDBFLAGS } {
append ::GDBFLAGS " -ex \"maint set target-non-stop $target_non_stop\""
append ::GDBFLAGS " -ex \"set non-stop $non_stop\""
append ::GDBFLAGS " -ex \"set displaced $displaced\""
append ::GDBFLAGS " -ex \"set schedule-multiple on\""
clean_restart $::binfile
}
gdb_test_no_output "set breakpoint condition-evaluation $condition_eval"
}
# Use the 'attach' command to attach to process with pid TESTPID. Return true
# if we believe GDB has attached and we are back at the GDB prompt, otherwise,
# return false.
proc attach_to {testpid} {
with_timeout_factor 2 {
set attached 0
set saw_attaching 0
gdb_test_multiple "attach $testpid" "attach" {
-re "Attaching to program.*process $testpid\r\n" {
set saw_attaching 1
exp_continue
}
-re "new threads in iteration" {
# Seen when "set debug libthread_db" is on.
exp_continue
}
-re "Reading symbols from|Expanding full symbols from" {
# Prevent -readnow timeout.
exp_continue
}
-re "is a zombie - the process has already terminated.*$::gdb_prompt " {
fail $gdb_test_name
}
-re "Unable to attach: .*$::gdb_prompt " {
fail $gdb_test_name
}
-re "\r\n$::gdb_prompt " {
if { $saw_attaching } {
set attached 1
pass $gdb_test_name
} else {
fail $gdb_test_name
}
}
}
}
return $attached
}
# After attaching to a multi-threaded inferior in non-stop mode, we expect to
# see a stop message from each thread. This proc waits for all of these stop
# messages. TID_RE is a regexp used to match the thread-id of the stopped
# thread.
#
# Return true if we saw a stop from each of the expected threads (based on the
# global N_THREADS value), otherwise, return false.
proc check_stops_after_non_stop_attach {tid_re} {
set any "\[^\r\n\]*"
# In non-stop, we will see one stop per thread after the prompt.
set stops 0
set test "seen all stops"
for {set thread 1} { $thread <= $::n_threads } { incr thread } {
if {[gdb_test_multiple "" $test {
-re "Thread ${tid_re} ${any} stopped" {
incr stops
}
}] != 0} {
break
}
}
# If we haven't seen all stops, then the
# gdb_test_multiple in the loop above will have
# already issued a FAIL.
if {$stops != $::n_threads} {
return false
}
pass $test
return true
}
# Prepare for a single test iteration. TESTPID is the pid of the process GDB
# will be attached too. NON_STOP indicates if GDB is configured in non-stop
# mode or not. ATTEMPT is the current attempt number, and ATTEMPTS is the
# maximum number of attempts we plan to run. TID_RE is a string used to match
# against a thread-id in GDB's stop messages.
#
# Return true if everything is prepared correctly, otherwise return false.
proc prepare_test_iter {testpid non_stop attempt attempts tid_re} {
if {![attach_to $testpid]} {
return false
}
if {$non_stop} {
if {![check_stops_after_non_stop_attach $tid_re]} {
return false
}
}
gdb_test "break ${::srcfile}:${::bp_lineno} if 0" "Breakpoint.*" \
"break LOC if 0"
if {$attempt < $attempts} {
# Kick the time out timer for another round.
gdb_test "print again = 1" " = 1" "reset timer in the inferior"
# Show the time we had left in the logs, in case
# something goes wrong.
gdb_test "print seconds_left" " = .*"
}
if {$non_stop} {
set cont_cmd "continue -a &"
} else {
set cont_cmd "continue &"
}
set cont_cmd_re [string_to_regexp $cont_cmd]
gdb_test_multiple $cont_cmd "" {
-re "^$cont_cmd_re\r\nContinuing\.\r\n$::gdb_prompt " {
pass $gdb_test_name
}
}
return true
}
# The test proper. See the description at the top of the file.
proc_with_prefix test_detach_command {condition_eval target_non_stop non_stop displaced} {
set test_spawn_id [spawn_wait_for_attach $::binfile]
set testpid [spawn_id_get_pid $test_spawn_id]
start_gdb_for_test $condition_eval $target_non_stop $non_stop $displaced
gdb_test "add-inferior" "Added inferior 2.*"
gdb_test "inferior 2" "Switching to .*"
gdb_load $::binfile
if {![runto setup_done]} {
fail "can't run to setup_done"
kill_wait_spawned_process $test_spawn_id
return
}
# Get the PID of the test process.
set pid_inf2 ""
gdb_test_multiple "p mypid" "get pid of inferior 2" {
-re " = ($::decimal)\r\n$::gdb_prompt $" {
set pid_inf2 $expect_out(1,string)
pass $gdb_test_name
}
}
set attempts 3
for {set attempt 1} { $attempt <= $attempts } { incr attempt } {
with_test_prefix "iter $attempt" {
gdb_test "inferior 1" "Switching to .*"
if {![prepare_test_iter $testpid $non_stop \
$attempt $attempts "$::decimal\.$::decimal"]} {
kill_wait_spawned_process $test_spawn_id
return
}
set running_count 0
set interrupted 0
set running_expected [expr ($::n_threads + 1) * 2]
gdb_test_multiple "info threads" "threads running" {
-re "\\(running\\)" {
incr running_count
exp_continue
}
-re "Cannot execute this command while the target is running.*$::gdb_prompt $" {
# Testing against a remote server that doesn't do
# non-stop mode. Explicitly interrupt. This
# doesn't test the same code paths in GDB, but
# it's still something.
set interrupted 1
gdb_test_multiple "interrupt" "" {
-re "$::gdb_prompt " {
gdb_test_multiple "" $gdb_test_name {
-re "received signal SIGINT, Interrupt" {
pass $gdb_test_name
}
}
}
}
}
-re "$::gdb_prompt " {
}
}
if { !$interrupted } {
set iterations 0
set max_iterations 10
while { $running_count < $running_expected } {
sleep 1
set running_count 0
gdb_test_multiple "info threads" "threads running" {
-re "\\(running\\)" {
incr running_count
exp_continue
}
-re "$::gdb_prompt " {
}
}
incr iterations
if { $iterations == $max_iterations } {
break
}
}
gdb_assert {$running_count == $running_expected} \
"all threads running"
}
gdb_test "detach" "Detaching from.*"
if {!$interrupted} {
# Now test whether inferior 2's thread were really left
# running. Currently an inline step-over stops all
# threads of all processes. If detach aborts such a step
# over, then threads of other inferiors should be
# re-resumed. Test for that by sending a signal to
# inferior 2.
remote_exec target "kill -USR1 ${pid_inf2}"
gdb_test_multiple "" "stop with SIGUSR1" {
-re "received signal SIGUSR1" {
pass $gdb_test_name
}
}
}
delete_breakpoints
}
}
kill_wait_spawned_process $test_spawn_id
}
# Similar to the proc above, but this time, instead of detaching using
# the 'detach' command, we quit GDB, this will also trigger a detach, but
# through a slightly different path, which can expose different bugs.
proc_with_prefix test_detach_quit {condition_eval target_non_stop \
non_stop displaced} {
# If debugging with target remote, check whether the all-stop variant
# of the RSP is being used. If so, we can't run the background tests.
if {!$non_stop
&& [target_info exists gdb_protocol]
&& ([target_info gdb_protocol] == "remote"
|| [target_info gdb_protocol] == "extended-remote")} {
start_gdb_for_test $condition_eval $target_non_stop \
$non_stop $displaced
if {![is_target_non_stop]} {
return
}
}
set test_spawn_id [spawn_wait_for_attach $::binfile]
set testpid [spawn_id_get_pid $test_spawn_id]
set attempts 3
for {set attempt 1} { $attempt <= $attempts } { incr attempt } {
with_test_prefix "iter $attempt" {
start_gdb_for_test $condition_eval $target_non_stop \
$non_stop $displaced
if {![prepare_test_iter $testpid $non_stop \
$attempt $attempts "$::decimal"]} {
kill_wait_spawned_process $test_spawn_id
return
}
gdb_test_multiple "with confirm off -- quit" "" {
eof {
pass $gdb_test_name
}
}
}
}
kill_wait_spawned_process $test_spawn_id
}
# The test program exits after a while, in case GDB crashes. Make it
# wait at least as long as we may wait before declaring a time out
# failure.
set options { "additional_flags=-DTIMEOUT=$timeout" debug pthreads }
if {[prepare_for_testing "failed to prepare" $testfile $srcfile $options] == -1} {
return -1
}
if ![runto_main] {
return -1
}
# Probe support for "set breakpoint condition-evaluation target".
# This setting influences who steps over the breakpoint, the (remote)
# target (e.g. gdbserver) or gdb, thus exposing issues on either the
# target or gdb.
set supports_condition_eval_target 1
set cmd "set breakpoint condition-evaluation target"
gdb_test_multiple $cmd "probe condition-evaluation target support" {
-re "warning: Target does not support breakpoint condition evaluation.\r\nUsing host evaluation mode instead.\r\n$gdb_prompt $" {
# Target doesn't support breakpoint condition evaluation on
# its side.
set supports_condition_eval_target 0
pass $gdb_test_name
}
-re "^$cmd\r\n$gdb_prompt $" {
pass $gdb_test_name
}
}
foreach_with_prefix breakpoint-condition-evaluation {"host" "target"} {
if {!$supports_condition_eval_target && ${breakpoint-condition-evaluation} == "target"} {
continue
}
foreach_with_prefix target-non-stop {"off" "on"} {
foreach_with_prefix non-stop {"off" "on"} {
if {${non-stop} && !${target-non-stop}} {
# "set non-stop" overrides "maint set
# target-non-stop", no use testing this combination.
continue
}
foreach_with_prefix displaced {"off" "auto"} {
test_detach_command ${breakpoint-condition-evaluation} \
${target-non-stop} ${non-stop} ${displaced}
test_detach_quit ${breakpoint-condition-evaluation} \
${target-non-stop} ${non-stop} ${displaced}
}
}
}
}