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Tom de Vries 1b9a9c30a0 [gdb/testsuite] Fix race in gdb.base/add-symbol-file-attach.exp
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:
...
    -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.
2023-09-04 13:54:36 +02:00
bfd Automatic date update in version.in 2023-09-04 00:00:24 +00:00
binutils PR30806, CPPFLAGS are missing for bfd/chew, syslex_wrap and sysinfo 2023-09-01 09:18:05 +09:30
config config: Fix host -rdynamic detection for build != host != target 2023-09-01 15:20:47 +00:00
contrib
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gas x86: unindent most of set_cpu_arch() 2023-09-01 12:29:44 +02:00
gdb [gdb/testsuite] Fix race in gdb.base/add-symbol-file-attach.exp 2023-09-04 13:54:36 +02:00
gdbserver gdbserver: i387_cache_to_xsave: fix copy dest of zmm registers 2023-09-01 22:13:01 -04:00
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