[patch] Fix double free on error while inserting the breakpoint

Jan Kratochvil
2008-11-22T21:41:21Z

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Hi,

SEGV reproducer:

x86 requires to build GDB with -lmcheck to make the crash reproducible.
Therefore no testsuite testcase is provided.
./gdb -nx -ex start -ex 'set breakpoint always-inserted on' -ex 'b *0' -ex 'delete 2' ./gdb

(Found on ia64 without -lmcheck.)

Regards,
Jan

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2008-11-22 Jan Kratochvil <jan.kratochvil@redhat.com>

Fix double free on error inserting the breakpoint instruction.
* breakpoint.c (create_breakpoints): Move the
update_global_location_list call to ...
(break_command_really): ... here together with the second local call
both unified after all the cleanups.

--- gdb/breakpoint.c 22 Nov 2008 04:41:45 -0000 1.362
+++ gdb/breakpoint.c 22 Nov 2008 20:10:07 -0000
@@ -5257,8 +5257,6 @@ create_breakpoints (struct symtabs_and_l
cond_string, type, disposition,
thread, ignore_count, ops, from_tty);
}
-
- update_global_location_list (1);
}

/* Parse ARG which is assumed to be a SAL specification possibly
@@ -5579,7 +5577,6 @@ break_command_really (char *arg, char *c
b->condition_not_parsed = 1;
b->ops = ops;

- update_global_location_list (1);
mention (b);
}

@@ -5591,6 +5588,11 @@ break_command_really (char *arg, char *c
discard_cleanups (breakpoint_chain);
/* But cleanup everything else. */
do_cleanups (old_chain);
+
+ /* Have already BREAKPOINT_CHAIN discarded as we may get an exception while
+ inserting the breakpoints which would double-free the resources both by
+ BREAKPOINT_CHAIN now and during DELETE_BREAKPOINT in the future. */