From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mathieu Poirier , Suzuki K Poulose , Sasha Levin Subject: [PATCH 4.14 095/222] coresight: etb10: Fix handling of perf mode Date: Sun, 11 Nov 2018 14:23:12 -0800 Message-Id: <20181111221656.430309087@linuxfoundation.org> In-Reply-To: <20181111221647.665769131@linuxfoundation.org> References: <20181111221647.665769131@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Suzuki K Poulose [ Upstream commit 987d1e8dcd370d96029a3d76a0031b043c4a69ae ] If the ETB is already enabled in sysfs mode, the ETB reports success even if a perf mode is requested. Fix this by checking the requested mode. Cc: Mathieu Poirier Signed-off-by: Suzuki K Poulose Signed-off-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-etb10.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -155,6 +155,10 @@ static int etb_enable(struct coresight_d if (val == CS_MODE_PERF) return -EBUSY; + /* Don't let perf disturb sysFS sessions */ + if (val == CS_MODE_SYSFS && mode == CS_MODE_PERF) + return -EBUSY; + /* Nothing to do, the tracer is already enabled. */ if (val == CS_MODE_SYSFS) goto out;