diff options
Diffstat (limited to 'kernel/tracepoint.c')
| -rw-r--r-- | kernel/tracepoint.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index e92f3fb8887a..26efd22f0633 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -221,7 +221,7 @@ static void *func_remove(struct tracepoint_func **funcs, return old; } -static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func *tp_funcs) +static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func *tp_funcs, bool sync) { void *func = tp->iterator; @@ -229,8 +229,17 @@ static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func if (!tp->static_call_key) return; - if (!tp_funcs[1].func) + if (!tp_funcs[1].func) { func = tp_funcs[0].func; + /* + * If going from the iterator back to a single caller, + * we need to synchronize with __DO_TRACE to make sure + * that the data passed to the callback is the one that + * belongs to that callback. + */ + if (sync) + tracepoint_synchronize_unregister(); + } __static_call_update(tp->static_call_key, tp->static_call_tramp, func); } @@ -265,7 +274,7 @@ static int tracepoint_add_func(struct tracepoint *tp, * include/linux/tracepoint.h using rcu_dereference_sched(). */ rcu_assign_pointer(tp->funcs, tp_funcs); - tracepoint_update_call(tp, tp_funcs); + tracepoint_update_call(tp, tp_funcs, false); static_key_enable(&tp->key); release_probes(old); @@ -297,11 +306,12 @@ static int tracepoint_remove_func(struct tracepoint *tp, tp->unregfunc(); static_key_disable(&tp->key); + rcu_assign_pointer(tp->funcs, tp_funcs); } else { - tracepoint_update_call(tp, tp_funcs); + rcu_assign_pointer(tp->funcs, tp_funcs); + tracepoint_update_call(tp, tp_funcs, + tp_funcs[0].func != old[0].func); } - - rcu_assign_pointer(tp->funcs, tp_funcs); release_probes(old); return 0; } |