forked from Imagelibrary/binutils-gdb
1b9a9c30a0
When running test-case gdb.base/add-symbol-file-attach.exp with target board
unix/-m32, we run into:
...
(gdb) attach 3955^M
Attaching to process 3955^M
Load new symbol table from "add-symbol-file-attach"? (y or n) y^M
Reading symbols from add-symbol-file-attach/add-symbol-file-attach...^M
Reading symbols from /lib/libm.so.6...^M
Reading symbols from /usr/lib/debug/lib/libm-2.31.so-i386.debug...^M
Reading symbols from /lib/libc.so.6...^M
Reading symbols from /usr/lib/debug/lib/libc-2.31.so-i386.debug...^M
Reading symbols from /lib/ld-linux.so.2...^M
Reading symbols from /usr/lib/debug/lib/ld-2.31.so-i386.debug...^M
0xf7f53549 in __kernel_vsyscall ()^M
(gdb) FAIL: gdb.base/add-symbol-file-attach.exp: attach
...
The test fails because this regexp is used:
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-re ".*in \[_A-Za-z0-9\]*pause.*$gdb_prompt $" {
...
The regexp attempts to detect that the exec is somewhere in pause ():
...
int
main (int argc, char **argv)
{
pause ();
return 0;
}
...
but when the exec is blocked in pause, the backtrace is:
...
(gdb) bt
#0 0xf7fd2549 in __kernel_vsyscall ()
#1 0xf7d84966 in __libc_pause () at ../sysdeps/unix/sysv/linux/pause.c:29
#2 0x0804844c in main (argc=1, argv=0xffffce84)
at /data/vries/gdb/src/gdb/testsuite/gdb.base/add-symbol-file-attach.c:26
...
We could simply extend the regexp to also match __kernel_vsyscall, but the
more fundamental problem is that the test is racy.
The attach can happen before the exec is blocked in pause (), somewhere in the
dynamic linker resolving the call to pause, in main or even earlier.
Note that for the test-case to be effective, the exec is not required to be in
pause (). I added a "while (1);" loop at the start of main, reverted the
patch fixing the corresponding PR and reproduced the problem it's supposed to
detect.
Fix this by simply matching the "Reading symbols from" line, similar to what
an earlier test is doing.
While we're at it, rewrite the earlier test to also use the -wrap idiom.
Tested on x86_64-linux.
83 lines
2.6 KiB
Plaintext
83 lines
2.6 KiB
Plaintext
# Copyright (C) 2021-2023 Free Software Foundation, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# This is a test case for bug 27831:
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#
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# https://sourceware.org/bugzilla/show_bug.cgi?id=27831
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#
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# Prior to fixing this bug, GDB could be caused to assert by doing
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# the following: A simple program with a global was started outside
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# of GDB. Once GDB was started, the symbol file was loaded in an
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# atypical manner via the 'add-symbol-file' command. Then, the
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# program was attached to via the 'attach' command at which time the
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# symbol file was loaded again. Once attached, printing the global
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# variable in the program would trigger the assertion error.
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#
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# This is what the assert looked like:
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#
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# gdb/symtab.c:6599: internal-error: get_msymbol_address:
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# Assertion `(objf->flags & OBJF_MAINLINE) == 0' failed.
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require can_spawn_for_attach
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standard_testfile
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if {[build_executable $testfile.exp $testfile $srcfile debug] == -1} {
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untested "failed to compile"
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return -1
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}
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# Use 'spawn_wait_for_attach' to start the test program running. It'll
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# also sleep for a short time in order to make sure that it's running
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# so that GDB may attach to it.
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set test_spawn_id [spawn_wait_for_attach $binfile]
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set testpid [spawn_id_get_pid $test_spawn_id]
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gdb_start
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# Load the symbol file in an atypical manner by using the add-symbol-file
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# command.
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set test "add-symbol-file before attach"
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gdb_test_multiple "add-symbol-file $binfile" $test {
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-re "add symbol table from file.*y or n. $" {
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send_gdb "y\n"
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exp_continue
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}
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-re -wrap "Reading symbols from .*" {
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pass $test
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}
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}
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# Attach to the process started above. GDB will want to load a "new"
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# symbol table, so handle that case.
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set test "attach"
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gdb_test_multiple "attach $testpid" $test {
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-re "Attaching to process.*Load new symbol table.*y or n. $" {
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send_gdb "y\n"
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exp_continue
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}
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-re -wrap "Reading symbols from .*" {
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pass $test
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}
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}
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# Print out the value of the global. Prior to fixing bug 27831, GDB
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# would assert while executing this command.
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gdb_test "print foo" "42"
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