If you try to call a function in the inferior from user-defined
breakpoint commands, GDB crashes:
$ ./gdb -nx -q ./gdb
(gdb) break main
Breakpoint 1 at 0x8074686: file
../../../source/cygnus.cygnus/gdb/gdb.c, line 29.
(gdb) commands
Type commands for when breakpoint 1 is hit, one per line.
End with a line saying just "end".
>print (int) printf ("bobo\n")
>end
(gdb) run
Starting program: /home/klee/build/cygnus.cygnus/gdb/gdb
Breakpoint 1, main (argc=1, argv=0xbfffea34) at
../../../source/cygnus.cygnus/gdb/gdb.c:29
29 memset (&args, 0, sizeof args);
Program received signal SIGSEGV, Segmentation fault.
0x0807a246 in free_command_lines (lptr=0x18) at
../../../source/cygnus.cygnus/gdb/cli/cli-script.c:983
I believe this problem was introduced in the changes to breakpoint.c on
2002-08-26 --- the problem is that stop_bpstat gets cleared as part of
the cleanup after hand_function_call, which now includes removing the
commands data. But unfortunately, it's restored by
restore_inferior_status, including a pointer to now-obsolete commands,
which eventually causes the crash in free_command_lines.
save_inferior_status tries to "do the right thing," by making a copy of
stop_bpstat, but unfortunately, stop_bpstat only does a shallow copy,
not a deep one.
The following patch updates stop_bpstat to do a deep copy of the
commands and the old watchpoint value. It doesn't copy the breakpoint,
since I suspect this is supposed to just be a reference, and it's not
freed in clear_bpstat.
2002-10-29 Klee Dienes <kdienes@xxxxxxxxx>
* breakpoint.c (bpstat_copy): Copy the command lines as well
as the old value, to match what is freed in bpstat_clear.
* Makefile.in: Rename INTL_DEPS to INTL_DEP, to match other
variable names.
Index: breakpoint.c
===================================================================
RCS file: /cvs/Darwin/src/live/cygnus/src/gdb/breakpoint.c,v
retrieving revision 1.48
diff -u -r1.48 breakpoint.c
--- breakpoint.c 2002/10/26 09:20:12 1.48
+++ breakpoint.c 2002/10/30 09:01:01
@@ -1844,6 +1844,10 @@
{
tmp = (bpstat) xmalloc (sizeof (*tmp));
memcpy (tmp, bs, sizeof (*tmp));
+ if (bs->commands != NULL)
+ tmp->commands = copy_command_lines (bs->commands);
+ if (bs->old_val != NULL)
+ tmp->old_val = value_copy (bs->old_val);
if (p == NULL)
/* This is the first thing in the chain. */
retval = tmp;
This patch adds a check for calls to the inferior to the testsuite.
The first part is straightforward --- it adds a call to the inferior to
the initial "silent" breakpoint check, and checks for the correct
output from it. The second part, I'm less sure about: it makes a
second call to marker2(), after setting breakpoint commands on it to
call the inferior as well. Currently, these commands aren't hit (and
the test fails). I'm appending the test-suite part of the patch as an
attachment, because, as you all know, my mailer is officially weird.
2002-10-29 Klee Dienes <kdienes@xxxxxxxxx>
* gdb.base/break.exp: Add multiple calls to the inferior in
the user-commands for 'break 79'. Add a check for the calls
to the inferior in the check for the result. Add new test, to
check that user-defined breakpoint commands are called for
functions
called by the user (currently fails).
testsuite-diffs.txt
Description: Text document
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