On transition from 2->1 callees, we should be comparing .data rather than .func, because the same callback can be registered twice with different data, and what we care about here is that the data of array element 0 is unchanged to skip rcu sync.
Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.... Fixes: d25e37d89dd2 ("tracepoint: Optimize using static_call()") Fixes: 547305a64632 ("tracepoint: Fix out of sync data passing by static caller") Fixes: 352384d5c84e ("tracepoints: Update static_call before tp_funcs when adding a tracepoint") Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Steven Rostedt rostedt@goodmis.org Cc: Ingo Molnar mingo@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: "Paul E. McKenney" paulmck@kernel.org Cc: Stefan Metzmacher metze@samba.org Cc: stable@vger.kernel.org # 5.10+ --- kernel/tracepoint.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index fc32821f8240..133b6454b287 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -338,7 +338,7 @@ static int tracepoint_remove_func(struct tracepoint *tp, } else { rcu_assign_pointer(tp->funcs, tp_funcs); tracepoint_update_call(tp, tp_funcs, - tp_funcs[0].func != old[0].func); + tp_funcs[0].data != old[0].data); } release_probes(old); return 0;