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(unknown [10.44.33.245]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0A81E3001D16; Fri, 21 Mar 2025 17:08:27 +0000 (UTC) From: Gabriele Paoloni To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Gabriele Paoloni Subject: [PATCH v2] tracing: fix return value in __ftrace_event_enable_disable for TRACE_REG_UNREGISTER Date: Fri, 21 Mar 2025 18:08:21 +0100 Message-ID: <20250321170821.101403-1-gpaoloni@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" When __ftrace_event_enable_disable invokes the class callback to unregister the event, the return value is not reported up to the caller, hence leading to event unregister failures being silently ignored. This patch assigns the ret variable to the invocation of the event unregister callback, so that its return value is stored and reported to the caller, and it raises a warning in case of error. Signed-off-by: Gabriele Paoloni --- Changes from v1: Added WARN_ON_ONCE(ret) according to the feedbacks from v1 RFC [1] [1] https://lore.kernel.org/linux-trace-kernel/20250314125725.6425-1-gpaolo= ni@redhat.com/T/#u --- kernel/trace/trace_events.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 513de9ceb80e..8e7603acca21 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -790,7 +790,9 @@ static int __ftrace_event_enable_disable(struct trace_e= vent_file *file, clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags); } =20 - call->class->reg(call, TRACE_REG_UNREGISTER, file); + ret =3D call->class->reg(call, TRACE_REG_UNREGISTER, file); + + WARN_ON_ONCE(ret); } /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */ if (file->flags & EVENT_FILE_FL_SOFT_MODE) --=20 2.48.1