From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Suzuki K Poulose , Mathieu Poirier , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.19 126/146] coresight: etb10: Fix handling of perf mode Date: Wed, 31 Oct 2018 19:05:21 -0400 Message-Id: <20181031230541.28822-126-sashal@kernel.org> In-Reply-To: <20181031230541.28822-1-sashal@kernel.org> References: <20181031230541.28822-1-sashal@kernel.org> List-ID: 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 --- drivers/hwtracing/coresight/coresight-etb10.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index 306119eaf16a..0dad8626bcfb 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -147,6 +147,10 @@ static int etb_enable(struct coresight_device *csdev, u32 mode) 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; -- 2.17.1