1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index a1b466d17c17..c718fef28617 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -596,6 +596,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
                 BUG_ON((uprobe->offset & ~PAGE_MASK) +
                                 UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
 
+                smp_wmb(); /* pairs with rmb() in find_active_uprobe() */
                 uprobe->flags |= UPROBE_COPY_INSN;
         }
 
@@ -1436,6 +1437,14 @@ static void handle_swbp(struct pt_regs *regs)
                 }
                 return;
         }
+        /*
+         * TODO: move copy_insn/etc into _register and remove this hack.
+         * After we hit the bp, _unregister + _register can install the
+         * new and not-yet-analyzed uprobe at the same address, restart.
+         */
+        smp_rmb(); /* pairs with wmb() in install_breakpoint() */
+        if (unlikely(!(uprobe->flags & UPROBE_COPY_INSN)))
+                goto restart;
 
         utask = current->utask;
         if (!utask) {