[pushed/master+7.10] gdbserver: move_out_of_jump_pad_callback misses switching current thread
Commit Message
While hacking on the fix for PR threads/18600 (Threads left stopped
after fork+thread spawn), I once saw its test (fork-plus-threads.exp)
FAIL against gdbserver because move_out_of_jump_pad_callback has a
gdb_breakpoint_here call, and the caller isn't making sure the current
thread points to the right thread. In the case I saw, the current
thread pointed to the wrong process, so gdb_breakpoint_here returned
the wrong answer. Unfortunately I didn't save logs. Still, seems
obvious enough and it should fix a potential occasional racy FAIL.
Tested on x86_64 Fedora 20.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (move_out_of_jump_pad_callback): Temporarily switch
the current thread.
---
gdb/gdbserver/ChangeLog | 5 +++++
gdb/gdbserver/linux-low.c | 7 +++++++
2 files changed, 12 insertions(+)
@@ -1,5 +1,10 @@
2015-08-06 Pedro Alves <palves@redhat.com>
+ * linux-low.c (move_out_of_jump_pad_callback): Temporarily switch
+ the current thread.
+
+2015-08-06 Pedro Alves <palves@redhat.com>
+
* linux-low.c (linux_write_memory): Rewrite debug output to avoid
reading beyond the passed in buffer length.
@@ -3664,6 +3664,7 @@ static void
move_out_of_jump_pad_callback (struct inferior_list_entry *entry)
{
struct thread_info *thread = (struct thread_info *) entry;
+ struct thread_info *saved_thread;
struct lwp_info *lwp = get_thread_lwp (thread);
int *wstat;
@@ -3675,6 +3676,10 @@ move_out_of_jump_pad_callback (struct inferior_list_entry *entry)
}
gdb_assert (lwp->stopped);
+ /* For gdb_breakpoint_here. */
+ saved_thread = current_thread;
+ current_thread = thread;
+
wstat = lwp->status_pending_p ? &lwp->status_pending : NULL;
/* Allow debugging the jump pad, gdb_collect, etc. */
@@ -3702,6 +3707,8 @@ move_out_of_jump_pad_callback (struct inferior_list_entry *entry)
}
else
lwp_suspended_inc (lwp);
+
+ current_thread = saved_thread;
}
static int