From bfacd19d64c76b740a4a9c18dce4277e4a9afde5 Mon Sep 17 00:00:00 2001 From: Don Breazeal Date: Thu, 28 May 2015 13:12:01 -0700 Subject: Initialize last_resume_kind for remote fork child This patch fixes some intermittent test failures in gdb.base/foll-vfork.exp where a vfork child would be (incorrectly) resumed when handling the vfork event. In this case the result was a subsequent event reported to the client side as a SIGTRAP delivered to the as-yet-unknown child thread. The new thread was resumed (incorrectly) in linux-low.c when resume_stopped_resumed_lwps was called from linux_wait_for_event_filtered after the vfork event had been handled in handle_extended_wait. Gdbserver/linux-low.c's add_thread function creates threads with last_resume_kind == resume_continue by default. This field is used by resume_stopped_resumed_lwps to decide whether to perform the resume: static void resume_stopped_resumed_lwps (struct inferior_list_entry *entry) { struct thread_info *thread = (struct thread_info *) entry; struct lwp_info *lp = get_thread_lwp (thread); if (lp->stopped && !lp->status_pending_p && thread->last_resume_kind != resume_stop && thread->last_status.kind == TARGET_WAITKIND_IGNORE) { So the fix is to make sure to set thread->last_resume_kind to resume_stop. Here we do that for new fork children in gdbserver/linux-low.c:handle_extended_wait. In addition, it seemed prudent to initialize lwp_info.status_pending_p for the new fork child. I also rearranged the initialization code so that all of the lwp_info initialization was together, rather than intermixed with thread_info and process_info initialization. Tested native, native-gdbserver, native-extended-gdbserver on x86_64 GNU/Linux. gdb/gdbserver/ * linux-low.c (handle_extended_wait): Initialize thread_info.last_resume_kind for new fork children. --- gdb/gdbserver/ChangeLog | 5 +++++ gdb/gdbserver/linux-low.c | 6 +++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 0f30c66d0ee..4e4f42935b6 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,8 @@ +2015-05-28 Don Breazeal + + * linux-low.c (handle_extended_wait): Initialize + thread_info.last_resume_kind for new fork children. + 2015-05-15 Pedro Alves * target.h (target_handle_new_gdb_connection): Rewrite using if diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c index 9f3ea4881ff..d763c66e5b1 100644 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -457,6 +457,7 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat) struct process_info *parent_proc; struct process_info *child_proc; struct lwp_info *child_lwp; + struct thread_info *child_thr; struct target_desc *tdesc; ptid = ptid_build (new_pid, new_pid, 0); @@ -479,6 +480,10 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat) child_lwp = add_lwp (ptid); gdb_assert (child_lwp != NULL); child_lwp->stopped = 1; + child_lwp->must_set_ptrace_flags = 1; + child_lwp->status_pending_p = 0; + child_thr = get_lwp_thread (child_lwp); + child_thr->last_resume_kind = resume_stop; parent_proc = get_thread_process (event_thr); child_proc->attached = parent_proc->attached; clone_all_breakpoints (&child_proc->breakpoints, @@ -488,7 +493,6 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat) tdesc = xmalloc (sizeof (struct target_desc)); copy_target_description (tdesc, parent_proc->tdesc); child_proc->tdesc = tdesc; - child_lwp->must_set_ptrace_flags = 1; /* Clone arch-specific process data. */ if (the_low_target.new_fork != NULL) -- cgit v1.2.1