From: Mathieu Desnoyers mathieu.desnoyers@efficios.com
commit f7ec4121256393e1d03274acdca73eb18958f27e upstream.
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.... Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba....
Cc: stable@vger.kernel.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 Fixes: 547305a64632 ("tracepoint: Fix out of sync data passing by static caller") Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/tracepoint.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -338,7 +338,7 @@ static int tracepoint_remove_func(struct } 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;