[PATCH 4/4] Fix PR gdb/19187 (process record over a fork causes internal error)

[Pedro Alves <palves@redhat.com>]

Right after a fork is detected, we detach breakpoints from the child
(detach_breakpoints), which calls into target_remove_breakpoint with
inferior_ptid pointing at the child process, but leaves the breakpoint
marked inserted (in the parent).

The problem is that record-full.c always deletes all knowledge of the
breakpoint.  Then when we later really delete the breakpoint from the
parent, we fail the assertion, since the breakpoint is unexpectedly
not found in the record-full.c breakpoint table.

The fix is simply to not forget about the breakpoint if we're
detaching it from a fork child.

gdb/ChangeLog:
2016-02-14  Pedro Alves  <palves@redhat.com>

	PR gdb/19187
	* record-full.c (record_full_remove_breakpoint): Don't remove the
	breakpoint from the record_full_breakpoints VEC if we're detaching
	the breakpoint from a fork child.

gdb/testsuite/ChangeLog:
2016-02-14  Pedro Alves  <palves@redhat.com>

	PR gdb/19187
	* gdb.reverse/waitpid-reverse.exp: Add comment and remove
	setup_kfails.
---
 gdb/record-full.c                             | 7 +++++--
 gdb/testsuite/gdb.reverse/waitpid-reverse.exp | 4 ++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/gdb/record-full.c b/gdb/record-full.c
index 418a346..e325869 100644
--- a/gdb/record-full.c
+++ b/gdb/record-full.c
@@ -1712,8 +1712,11 @@ record_full_remove_breakpoint (struct target_ops *ops,
 		return ret;
 	    }
 
-	  VEC_unordered_remove (record_full_breakpoint_p,
-				record_full_breakpoints, ix);
+	  if (reason == REMOVE_BREAKPOINT)
+	    {
+	      VEC_unordered_remove (record_full_breakpoint_p,
+				    record_full_breakpoints, ix);
+	    }
 	  return 0;
 	}
     }
diff --git a/gdb/testsuite/gdb.reverse/waitpid-reverse.exp b/gdb/testsuite/gdb.reverse/waitpid-reverse.exp
index d583953..e8a1690 100644
--- a/gdb/testsuite/gdb.reverse/waitpid-reverse.exp
+++ b/gdb/testsuite/gdb.reverse/waitpid-reverse.exp
@@ -18,6 +18,8 @@
 #
 # This test tests waitpid syscall for reverse execution.
 #
+# Also serves as regression test for gdb/19187 (recording across a
+# fork).
 
 if ![supports_reverse] {
     return
@@ -40,14 +42,12 @@ gdb_test "break marker2" \
     "Breakpoint $decimal at $hex: file .*$srcfile, line $decimal.*" \
     "set breakpoint at marker2"
 
-setup_kfail "gdb/19187" *-*-*
 gdb_continue_to_breakpoint "marker2" ".*$srcfile:.*"
 
 gdb_test "break marker1" \
     "Breakpoint $decimal at $hex: file .*$srcfile, line $decimal.*" \
     "set breakpoint at marker1"
 
-setup_kfail "gdb/19187" *-*-*
 gdb_test "reverse-continue" ".*$srcfile:$decimal.*" "reverse to marker1"
 
 # If the variable was recorded properly on syscall, the old contents (-1)
-- 
1.9.3