intel_th: Use correct method of finding hub

BugLink: http://bugs.launchpad.net/bugs/1786352
[ Upstream commit 9ad577087165478c9d9be82b15ed9bf2db5835f5 ]

Since commit 8edc514b01e9 ("intel_th: Make SOURCE devices children of the
root device") the hub is not the parent of SOURCE devices any more, so the
new helper function should be used for that instead of always using the
parent. The intel_th_set_output() path, however, still uses the old
logic, leading to the hub driver structure being aliased with something
else, like struct pci_driver or struct acpi_driver, and an incorrect call
to an address inferred from that, potentially resulting in a crash.

Fixes: 8edc514b01e9 ("intel_th: Make SOURCE devices children of the root device")
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
index 1a023e30488c66d4e7e58367a58a02252e6e63b0..c1793313bb0873fea10e263062f6e580d34c7670 100644 (file)
--- a/drivers/hwtracing/intel_th/core.c
+++ b/drivers/hwtracing/intel_th/core.c
@@ -935,7 +935,7 @@ EXPORT_SYMBOL_GPL(intel_th_trace_disable);
 int intel_th_set_output(struct intel_th_device *thdev,
                        unsigned int master)
 {
-       struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+       struct intel_th_device *hub = to_intel_th_hub(thdev);
        struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
 
        if (!hubdrv->set_output)