binutils-gdb/gdb/testsuite/gdb.python/py-recurse-unwind.c
Kevin Buettner bb1fe4acb8 Test case to detect recursive unwinding in Python-based unwinders.
This test case verifies that GDB will not attempt to invoke a python
unwinder recursively.

At the moment, the behavior exhibited by GDB looks like this:

    (gdb) source py-recurse-unwind.py
    Python script imported
    (gdb) b ccc
    Breakpoint 1 at 0x4004bd: file py-recurse-unwind.c, line 23.
    (gdb) run
    Starting program: py-recurse-unwind
    TestUnwinder: Recursion detected - returning early.
    TestUnwinder: Recursion detected - returning early.
    TestUnwinder: Recursion detected - returning early.
    TestUnwinder: Recursion detected - returning early.

    Breakpoint 1, ccc (arg=<unavailable>) at py-recurse-unwind.c:23
    23      }
    (gdb) bt
    #-1 ccc (arg=<unavailable>) at py-recurse-unwind.c:23
    Backtrace stopped: previous frame identical to this frame (corrupt stack?)

[I've shortened pathnames for easier reading.]

The desired / expected behavior looks like this:

    (gdb) source py-recurse-unwind.py
    Python script imported
    (gdb) b ccc
    Breakpoint 1 at 0x4004bd: file py-recurse-unwind.c, line 23.
    (gdb) run
    Starting program: py-recurse-unwind

    Breakpoint 1, ccc (arg=789) at py-recurse-unwind.c:23
    23      }
    (gdb) bt
    #0  ccc (arg=789) at py-recurse-unwind.c:23
    #1  0x00000000004004d5 in bbb (arg=456) at py-recurse-unwind.c:28
    #2  0x00000000004004ed in aaa (arg=123) at py-recurse-unwind.c:34
    #3  0x00000000004004fe in main () at py-recurse-unwind.c:40

Note that GDB's problems go well beyond the fact that it invokes the
unwinder recursively.  In the process it messes up some internal state
(the frame stash) leading to display of (only) the sentinel frame in
the backtrace.

gdb/testsuite/ChangeLog:

	* gdb.python/py-recurse-unwind.c: New file.
	* gdb.python/py-recurse-unwind.py: New file.
	* gdb.python/py-recurse-unwind.exp: New file.
2016-08-24 14:22:30 -07:00

42 lines
972 B
C

/* This test program is part of GDB, the GNU debugger.
Copyright 2016 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* This is the test program loaded into GDB by the py-recurse-unwind test. */
void
ccc (int arg)
{
}
void
bbb (int arg)
{
ccc (789);
}
void
aaa (int arg)
{
bbb (456);
}
int
main ()
{
aaa (123);
return 0;
}