4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Suzuki K Poulose <suzuki.poulose@xxxxxxx> [ Upstream commit fe470f5f7f684ed15bc49b6183a64237547910ff ] If we fail to find the input / output port for a LINK component while enabling a path, we should fail gracefully rather than assuming port "0". Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hwtracing/coresight/coresight.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -86,7 +86,7 @@ static int coresight_find_link_inport(st dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n", dev_name(&parent->dev), dev_name(&csdev->dev)); - return 0; + return -ENODEV; } static int coresight_find_link_outport(struct coresight_device *csdev) @@ -107,7 +107,7 @@ static int coresight_find_link_outport(s dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n", dev_name(&csdev->dev), dev_name(&child->dev)); - return 0; + return -ENODEV; } static int coresight_enable_sink(struct coresight_device *csdev) @@ -155,6 +155,9 @@ static int coresight_enable_link(struct else refport = 0; + if (refport < 0) + return refport; + if (atomic_inc_return(&csdev->refcnt[refport]) == 1) { if (link_ops(csdev)->enable) { ret = link_ops(csdev)->enable(csdev, inport, outport);