From 7a5b8de98b606d8994779b9ebc5dde22c8ae24ba Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 5 Aug 2021 09:27:15 -0400 Subject: [PATCH] tracepoint: static call: Compare data on transition from 2->1 callees 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://lkml.kernel.org/r/20210805132717.23813-2-mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/ Cc: stable@vger.kernel.org Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Andrew Morton Cc: "Paul E. McKenney" Cc: Stefan Metzmacher Fixes: 2145dc4ef911 ("tracepoint: Fix out of sync data passing by static caller") Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (VMware) --- kernel/tracepoint.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index fc32821f8240b..133b6454b287a 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; -- 2.39.5