Commit a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices") brings in new subdevice addition/removal logic that's broken for "host mode": the SWITCH device has no children to begin with, which is not handled in the code. This results in a null dereference bug later down the path.

This patch fixes the subdevice removal code to handle host mode correctly.

Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Fixes: a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices") CC: stable@vger.kernel.org # v4.14+ --- drivers/hwtracing/intel_th/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index da962aa2cef5..4e70ecee2103 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -139,7 +139,8 @@ static int intel_th_remove(struct device *dev) th->thdev[i] = NULL; }

- th->num_thdevs = lowest; + if (lowest >= 0) + th->num_thdevs = lowest; }

if (thdrv->attr_group)