Always prune step breakpoints when uninstalling from memory

On completion of an initial single step, we can and should discard these
breakpoints, even though the thread may not be "stopping" and go on to
continue in free-run.  They have served their purpose at this point and
we would like to avoid any other thread encountering them.

Also, whenever uninstall_breakpoints() is called, it is because we are
cycling a process's threads and are about to run resume_threads() which
currently does the work of re-computing a thread's step breakpoints if a
previous single step was interrupted, whether or not the step
breakpoints for that instant have already been figured.  So this also
addresses a bug where one thread, with repeatedly interrupted single
steps, would accumulate more and more redundant breakpoint entries until
it was finally able to proceed and eventually stop.

Signed-off-by: Matt Hunter <m@lfurio.us>

1 files changed, 6 insertions, 1 deletions

diff --git a/debugger.c b/debugger.c
index 173acbd..33bdbc0 100644
--- a/debugger.c
+++ b/debugger.c
@@ -96,7 +96,12 @@ static void uninstall_breakpoints(struct thread *th) {
             b->installed = 0;
         }
 
-        if (b->previously_installed && b->enabled < 0) {
+        if (b->step) {
+            struct breakpoint *del = b;
+            b = b->next;
+            list_remove(del);
+            free(del);
+        } else if (b->enabled < 0 && b->previously_installed) {
             struct thread *t = NULL;
             if (b->tid == 0 || ((t = thread_by_id(th->proc, b->tid)) && !t->doing)) {
                 struct breakpoint *del = b;