gdb/testsuite/gdb.threads/attach-many-short-lived-threads.exp

   1 # Copyright 2008-2024 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 # Test attaching to a program that is constantly spawning short-lived
  17 # threads.  The stresses the edge cases of attaching to threads that
  18 # have just been created or are in process of dying.  In addition, the
  19 # test attaches, debugs, detaches, reattaches in a loop a few times,
  20 # to stress the behavior of the debug API around detach (some systems
  21 # end up leaving stale state behind that confuse the following
  22 # attach).
  23
  24 # Return true if the running version of DejaGnu is known to not be
  25 # able to run this test.
  26 proc bad_dejagnu {} {
  27     set dj_ver [dejagnu_version]
  28     set dj_ver_major [lindex $dj_ver 0]
  29     set dj_ver_minor [lindex $dj_ver 1]
  30
  31     # DejaGnu versions prior to 1.6 manage to kill the wrong process
  32     # due to PID-reuse races.  Since this test spawns many threads, it
  33     # widens the race window a whole lot, enough that the inferior is
  34     # often killed, and thus the test randomly fails.  See:
  35     # http://lists.gnu.org/archive/html/dejagnu/2015-07/msg00005.html
  36     # The fix added a close_wait_program procedure.  If that procedure
  37     # is defined, and DejaGnu is older than 1.6, assume that means the
  38     # fix was backported.
  39     if {$dj_ver_major == 1
  40         && ($dj_ver_minor < 6 && [info procs close_wait_program] == "")} {
  41         return 1
  42     }
  43
  44     return 0
  45 }
  46
  47 if {[bad_dejagnu]} {
  48     unsupported "broken DejaGnu"
  49     return 0
  50 }
  51
  52 require can_spawn_for_attach
  53
  54 standard_testfile
  55
  56 # The test proper.  See description above.
  57
  58 proc test {} {
  59     global binfile
  60     global gdb_prompt
  61     global decimal
  62
  63     set test_spawn_id [spawn_wait_for_attach $binfile]
  64     set testpid [spawn_id_get_pid $test_spawn_id]
  65
  66     set attempts 10
  67     for {set attempt 1} { $attempt <= $attempts } { incr attempt } {
  68         with_test_prefix "iter $attempt" {
  69             set attached 0
  70             set eperm 0
  71             set test "attach"
  72             gdb_test_multiple "attach $testpid" $test {
  73                 -re "new threads in iteration" {
  74                     # Seen when "set debug libthread_db" is on.
  75                     exp_continue
  76                 }
  77                 -re "warning: Cannot attach to lwp $decimal: Operation not permitted" {
  78                     # On Linux, PTRACE_ATTACH sometimes fails with
  79                     # EPERM, even though /proc/PID/status indicates
  80                     # the thread is running.
  81                     set eperm 1
  82                     exp_continue
  83                 }
  84                 -re "debugger service failed.*$gdb_prompt $" {
  85                     fail $test
  86                 }
  87                 -re "$gdb_prompt $" {
  88                     if {$eperm} {
  89                         xfail "$test (EPERM)"
  90                     } else {
  91                         pass $test
  92                     }
  93                 }
  94                 -re "Attaching to program.*process $testpid.*$gdb_prompt $" {
  95                     pass $test
  96                 }
  97             }
  98
  99             # Sleep a bit and try updating the thread list.  We should
 100             # know about all threads already at this point.  If we see
 101             # "New Thread" or similar being output, then "attach" is
 102             # failing to actually attach to all threads in the process,
 103             # which would be a bug.
 104             sleep 1
 105
 106             set test "no new threads"
 107             set status 1
 108             gdb_test_multiple "info threads" $test -lbl {
 109                 -re "\r\n\[^\r\n\]*New " {
 110                     set status 0
 111                     exp_continue
 112                 }
 113                 -re -wrap "" {
 114                     if { $status == 1 } {
 115                         pass $gdb_test_name
 116                     } else {
 117                         fail $gdb_test_name
 118                     }
 119                 }
 120             }
 121
 122             # Force breakpoints always inserted, so that threads we might
 123             # have failed to attach to hit them even when threads we do
 124             # know about are stopped.
 125             gdb_test_no_output "set breakpoint always-inserted on"
 126
 127             # Run to a breakpoint a few times.  A few threads should spawn
 128             # and die meanwhile.  This checks that thread creation/death
 129             # events carry on correctly after attaching.  Also, be
 130             # detaching from the program and reattaching, we check that
 131             # the program doesn't die due to gdb leaving a pending
 132             # breakpoint hit on a new thread unprocessed.
 133             gdb_test "break break_fn" "Breakpoint.*"
 134
 135             # Wait a bit, to give time for most threads to hit the
 136             # breakpoint, including threads we might have failed to
 137             # attach.
 138             sleep 2
 139
 140             set bps 3
 141             for {set bp 1} { $bp <= $bps } { incr bp } {
 142                 gdb_test "continue" "Breakpoint.*" "break at break_fn: $bp"
 143             }
 144
 145             if {$attempt < $attempts} {
 146                 # Kick the time out timer for another round.
 147                 gdb_test "print again = 1" " = 1" "reset timer in the inferior"
 148                 # Show the time we had left in the logs, in case
 149                 # something goes wrong.
 150                 gdb_test "print seconds_left" " = .*"
 151
 152                 gdb_test "detach" "Detaching from.*"
 153             } else {
 154                 gdb_test "kill" "" "kill process" "Kill the program being debugged.*y or n. $" "y"
 155             }
 156
 157             gdb_test_no_output "set breakpoint always-inserted off"
 158             delete_breakpoints
 159         }
 160     }
 161     kill_wait_spawned_process $test_spawn_id
 162 }
 163
 164 # The test program exits after a while, in case GDB crashes.  Make it
 165 # wait at least as long as we may wait before declaring a time out
 166 # failure.
 167 set options { "additional_flags=-DTIMEOUT=$timeout" debug pthreads }
 168
 169 if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
 170          $options] == -1} {
 171     return -1
 172 }
 173
 174 test