1# Copyright (C) 2015-2020 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 exercises the case of stopping for a breakpoint hit of one 17# thread, then switching to a thread that has a status pending and 18# continuing. 19 20if [target_info exists gdb,nointerrupts] { 21 verbose "Skipping continue-pending-status.exp because of nointerrupts." 22 return 23} 24 25standard_testfile 26 27if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] { 28 return -1 29} 30 31if ![runto_main] { 32 untested "could not run to main" 33 return -1 34} 35 36set break_line [gdb_get_line_number "break here"] 37 38# Return current thread's number. 39 40proc get_current_thread {} { 41 global gdb_prompt 42 43 set thread "" 44 set msg "get thread number" 45 gdb_test_multiple "print /x \$_thread" $msg { 46 -re "\\$\[0-9\]* = (0x\[0-9a-zA-Z\]+).*$gdb_prompt $" { 47 set thread $expect_out(1,string) 48 pass "$msg" 49 } 50 } 51 return ${thread} 52} 53 54# There are two threads in the program that are running the same tight 55# loop, where we place a breakpoint. Sometimes we'll get a breakpoint 56# trigger for thread 2, with the breakpoint event of thread 3 pending, 57# other times the opposite. The original bug that motivated this test 58# depended on the event thread being the highest numbered thread. We 59# try the same multiple times, which should cover both threads 60# reporting the event. 61 62set attempts 20 63 64# These track whether we saw events for both threads 2 and 3. If the 65# backend always returns the breakpoint hit for the same thread, then 66# it fails to make sure threads aren't starved, and we'll fail the 67# assert after the loop. 68set saw_thread_2 0 69set saw_thread_3 0 70 71for {set i 0} {$i < $attempts} {incr i} { 72 with_test_prefix "attempt $i" { 73 gdb_test "b $srcfile:$break_line" \ 74 "Breakpoint .* at .*$srcfile, line $break_line.*" \ 75 "set break in tight loop" 76 gdb_test "continue" \ 77 "$srcfile:$break_line.*" \ 78 "continue to tight loop" 79 80 # Switch to the thread that did _not_ report the event (and 81 # thus may have a pending status). At the time this test was 82 # written this was necessary to make linux-nat.c short-circuit 83 # the resume and go straight to consuming the pending event. 84 set thread [get_current_thread] 85 if {$thread == 2} { 86 incr saw_thread_2 87 set thread 3 88 } else { 89 incr saw_thread_3 90 set thread 2 91 } 92 gdb_test "thread $thread" \ 93 "Switching to thread $thread .*" \ 94 "switch to non-event thread" 95 96 # Delete all breakpoints so that continuing doesn't switch 97 # back to the event thread to do a step-over, which would mask 98 # away the original bug, which depended on the event thread 99 # still having TARGET_STOPPED_BY_SW_BREAKPOINT stop_reason. 100 delete_breakpoints 101 102 # In the original bug, continuing would trigger an internal 103 # error in the linux-nat.c backend. 104 105 set msg "continue for ctrl-c" 106 gdb_test_multiple "continue" $msg { 107 -re "Continuing" { 108 pass $msg 109 } 110 } 111 112 # Wait a bit for GDB to give the terminal to the inferior, 113 # otherwise ctrl-c too soon can result in a "Quit". 114 sleep 1 115 send_gdb "\003" 116 117 set msg "caught interrupt" 118 gdb_test_multiple "" $msg { 119 -re "Thread .* received signal SIGINT.*$gdb_prompt $" { 120 pass $msg 121 } 122 } 123 } 124} 125 126verbose -log "saw_thread_2=$saw_thread_2" 127verbose -log "saw_thread_3=$saw_thread_3" 128 129gdb_assert {$saw_thread_2 > 0 && $saw_thread_3 > 0} "no thread starvation" 130