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tracepoint: static call: Compare data on transition from 2->1 callees

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commit f7ec412125 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.com
Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/

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: 547305a646 ("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>
This commit is contained in:
Mathieu Desnoyers
2021-08-05 09:27:15 -04:00
committed by Greg Kroah-Hartman
parent 046e12323a
commit 14673e1929
1 changed files with 1 additions and 1 deletions
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2
kernel/tracepoint.c
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@@ -359,7 +359,7 @@ 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;