]>
Commit | Line | Data |
---|---|---|
b811d2c2 | 1 | # Copyright 2018-2020 Free Software Foundation, Inc. |
7010835a AB |
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 script tries to expose a bug in some of the uses of | |
17 | # waitpid in the Linux native support within GDB. The problem was | |
18 | # spotted on systems which were heavily loaded when attaching to | |
19 | # threaded test programs. What happened was that during the initial | |
20 | # attach, the loop of waitpid calls that normally received the stop | |
21 | # events from each of the threads in the inferior was not receiving a | |
22 | # stop event for some threads (the kernel just hadn't sent the stop | |
23 | # event yet). | |
24 | # | |
25 | # GDB would then trigger a call to stop_all_threads which would | |
26 | # continue to wait for all of the outstanding threads to stop, when | |
27 | # the outstanding stop events finally arrived GDB would then | |
28 | # (incorrectly) discard the stop event, resume the thread, and | |
29 | # continue to wait for the thread to stop.... which it now never | |
30 | # would. | |
31 | # | |
32 | # In order to try and expose this issue reliably, this test preloads a | |
33 | # library that intercepts waitpid calls. All waitpid calls targeting | |
34 | # pid -1 with the WNOHANG flag are rate limited so that only 1 per | |
35 | # second can complete. Additional calls are forced to return 0 | |
36 | # indicating no event waiting. This is enough to trigger the bug | |
37 | # during the attach phase. | |
38 | ||
39 | # This test only works on Linux | |
40 | if { ![isnative] || [is_remote host] || [use_gdb_stub] | |
41 | || ![istarget *-linux*] } { | |
42 | continue | |
43 | } | |
44 | ||
45 | standard_testfile | |
46 | ||
47 | set libfile slow-waitpid | |
48 | set libsrc "${srcdir}/${subdir}/${libfile}.c" | |
49 | set libobj [standard_output_file ${libfile}.so] | |
50 | ||
51 | with_test_prefix "compile preload library" { | |
52 | # Compile the preload library. We only get away with this as we | |
53 | # limit this test to running when ISNATIVE is true. | |
54 | if { [gdb_compile_shlib_pthreads \ | |
55 | $libsrc $libobj {debug}] != "" } then { | |
56 | return -1 | |
57 | } | |
58 | } | |
59 | ||
60 | with_test_prefix "compile test executable" { | |
61 | # Compile the test program | |
62 | if { [gdb_compile_pthreads \ | |
63 | "${srcdir}/${subdir}/${srcfile}" "${binfile}" \ | |
64 | executable {debug}] != "" } { | |
65 | return -1 | |
66 | } | |
67 | } | |
68 | ||
69 | # Spawn GDB with LIB preloaded with LD_PRELOAD. | |
70 | ||
71 | proc gdb_spawn_with_ld_preload {lib} { | |
72 | global env | |
73 | ||
74 | save_vars { env(LD_PRELOAD) } { | |
75 | if { ![info exists env(LD_PRELOAD) ] | |
76 | || $env(LD_PRELOAD) == "" } { | |
77 | set env(LD_PRELOAD) "$lib" | |
78 | } else { | |
79 | append env(LD_PRELOAD) ":$lib" | |
80 | } | |
81 | ||
82 | gdb_start | |
83 | } | |
84 | } | |
85 | ||
86 | # Run test program in the background. | |
87 | set test_spawn_id [spawn_wait_for_attach $binfile] | |
88 | set testpid [spawn_id_get_pid $test_spawn_id] | |
89 | ||
90 | # Start GDB with preload library in place. | |
91 | gdb_spawn_with_ld_preload $libobj | |
92 | ||
93 | # Load binary, and attach to running program. | |
94 | gdb_load ${binfile} | |
95 | gdb_test "attach $testpid" "Attaching to program.*" "attach to target" | |
96 | ||
97 | gdb_exit | |
98 | ||
99 | # Kill of test program. | |
100 | kill_wait_spawned_process $test_spawn_id |