The unit tests crash when hotplug races the previous probe. This race requires that the loading of the nfit_test module be terminated with SIGTERM, and the module to be unloaded while the ars scan is still running. In contrast to the normal nfit driver, the unit test calls acpi_nfit_init() twice to simulate hotplug, whereas the nominal case goes through the acpi_nfit_notify() event handler. The acpi_nfit_notify() path is careful to flush the previous region registration before servicing the hotplug event. The unit test was missing this guarantee. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff810cdce7>] pwq_activate_delayed_work+0x47/0x170 [..] Call Trace: [<ffffffff810ce186>] pwq_dec_nr_in_flight+0x66/0xa0 [<ffffffff810ce490>] process_one_work+0x2d0/0x680 [<ffffffff810ce331>] ? process_one_work+0x171/0x680 [<ffffffff810ce88e>] worker_thread+0x4e/0x480 [<ffffffff810ce840>] ? process_one_work+0x680/0x680 [<ffffffff810ce840>] ? process_one_work+0x680/0x680 [<ffffffff810d5343>] kthread+0xf3/0x110 [<ffffffff8199846f>] ret_from_fork+0x1f/0x40 [<ffffffff810d5250>] ? kthread_create_on_node+0x230/0x230 Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- tools/testing/nvdimm/test/nfit.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c index 5404efa578a3..dd48f421844c 100644 --- a/tools/testing/nvdimm/test/nfit.c +++ b/tools/testing/nvdimm/test/nfit.c @@ -13,6 +13,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/platform_device.h> #include <linux/dma-mapping.h> +#include <linux/workqueue.h> #include <linux/libnvdimm.h> #include <linux/vmalloc.h> #include <linux/device.h> @@ -1474,6 +1475,7 @@ static int nfit_test_probe(struct platform_device *pdev) if (nfit_test->setup != nfit_test0_setup) return 0; + flush_work(&acpi_desc->work); nfit_test->setup_hotplug = 1; nfit_test->setup(nfit_test); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html