From fbabd829fe76a72a6444f64361cf8b2a9848639d Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 18 Apr 2017 09:56:31 -0700 Subject: [PATCH] acpi, nfit: fix module unload vs workqueue shutdown race The workqueue may still be running when the devres callbacks start firing to deallocate an acpi_nfit_desc instance. Stop and flush the workqueue before letting any other devres de-allocations proceed. Reported-by: Linda Knippers Signed-off-by: Dan Williams --- drivers/acpi/nfit/core.c | 76 +++++++++++++++++++------------- drivers/acpi/nfit/nfit.h | 1 + tools/testing/nvdimm/test/nfit.c | 4 ++ 3 files changed, 51 insertions(+), 30 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 69c6cc77130c..261eea1d2906 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -2604,7 +2604,8 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc) return rc; } - queue_work(nfit_wq, &acpi_desc->work); + if (!acpi_desc->cancel) + queue_work(nfit_wq, &acpi_desc->work); return 0; } @@ -2650,32 +2651,11 @@ static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc) return 0; } -static void acpi_nfit_destruct(void *data) +static void acpi_nfit_unregister(void *data) { struct acpi_nfit_desc *acpi_desc = data; - struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus); - /* - * Destruct under acpi_desc_lock so that nfit_handle_mce does not - * race teardown - */ - mutex_lock(&acpi_desc_lock); - acpi_desc->cancel = 1; - /* - * Bounce the nvdimm bus lock to make sure any in-flight - * acpi_nfit_ars_rescan() submissions have had a chance to - * either submit or see ->cancel set. - */ - device_lock(bus_dev); - device_unlock(bus_dev); - - flush_workqueue(nfit_wq); - if (acpi_desc->scrub_count_state) - sysfs_put(acpi_desc->scrub_count_state); nvdimm_bus_unregister(acpi_desc->nvdimm_bus); - acpi_desc->nvdimm_bus = NULL; - list_del(&acpi_desc->list); - mutex_unlock(&acpi_desc_lock); } int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz) @@ -2693,7 +2673,7 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz) if (!acpi_desc->nvdimm_bus) return -ENOMEM; - rc = devm_add_action_or_reset(dev, acpi_nfit_destruct, + rc = devm_add_action_or_reset(dev, acpi_nfit_unregister, acpi_desc); if (rc) return rc; @@ -2787,9 +2767,10 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc) /* bounce the init_mutex to make init_complete valid */ mutex_lock(&acpi_desc->init_mutex); - mutex_unlock(&acpi_desc->init_mutex); - if (acpi_desc->init_complete) + if (acpi_desc->cancel || acpi_desc->init_complete) { + mutex_unlock(&acpi_desc->init_mutex); return 0; + } /* * Scrub work could take 10s of seconds, userspace may give up so we @@ -2798,6 +2779,7 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc) INIT_WORK_ONSTACK(&flush.work, flush_probe); COMPLETION_INITIALIZER_ONSTACK(flush.cmp); queue_work(nfit_wq, &flush.work); + mutex_unlock(&acpi_desc->init_mutex); rc = wait_for_completion_interruptible(&flush.cmp); cancel_work_sync(&flush.work); @@ -2834,10 +2816,12 @@ int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc) if (work_busy(&acpi_desc->work)) return -EBUSY; - if (acpi_desc->cancel) + mutex_lock(&acpi_desc->init_mutex); + if (acpi_desc->cancel) { + mutex_unlock(&acpi_desc->init_mutex); return 0; + } - mutex_lock(&acpi_desc->init_mutex); list_for_each_entry(nfit_spa, &acpi_desc->spas, list) { struct acpi_nfit_system_address *spa = nfit_spa->spa; @@ -2886,6 +2870,35 @@ static void acpi_nfit_put_table(void *table) acpi_put_table(table); } +void acpi_nfit_shutdown(void *data) +{ + struct acpi_nfit_desc *acpi_desc = data; + struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus); + + /* + * Destruct under acpi_desc_lock so that nfit_handle_mce does not + * race teardown + */ + mutex_lock(&acpi_desc_lock); + list_del(&acpi_desc->list); + mutex_unlock(&acpi_desc_lock); + + mutex_lock(&acpi_desc->init_mutex); + acpi_desc->cancel = 1; + mutex_unlock(&acpi_desc->init_mutex); + + /* + * Bounce the nvdimm bus lock to make sure any in-flight + * acpi_nfit_ars_rescan() submissions have had a chance to + * either submit or see ->cancel set. + */ + device_lock(bus_dev); + device_unlock(bus_dev); + + flush_workqueue(nfit_wq); +} +EXPORT_SYMBOL_GPL(acpi_nfit_shutdown); + static int acpi_nfit_add(struct acpi_device *adev) { struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL }; @@ -2933,12 +2946,15 @@ static int acpi_nfit_add(struct acpi_device *adev) rc = acpi_nfit_init(acpi_desc, (void *) tbl + sizeof(struct acpi_table_nfit), sz - sizeof(struct acpi_table_nfit)); - return rc; + + if (rc) + return rc; + return devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc); } static int acpi_nfit_remove(struct acpi_device *adev) { - /* see acpi_nfit_destruct */ + /* see acpi_nfit_unregister */ return 0; } diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h index fac098bfa585..58fb7d68e04a 100644 --- a/drivers/acpi/nfit/nfit.h +++ b/drivers/acpi/nfit/nfit.h @@ -239,6 +239,7 @@ static inline struct acpi_nfit_desc *to_acpi_desc( const u8 *to_nfit_uuid(enum nfit_uuids id); int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *nfit, acpi_size sz); +void acpi_nfit_shutdown(void *data); void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event); void __acpi_nvdimm_notify(struct device *dev, u32 event); int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm, diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c index d7fb1b894128..c2187178fb13 100644 --- a/tools/testing/nvdimm/test/nfit.c +++ b/tools/testing/nvdimm/test/nfit.c @@ -1851,6 +1851,10 @@ static int nfit_test_probe(struct platform_device *pdev) if (rc) return rc; + rc = devm_add_action_or_reset(&pdev->dev, acpi_nfit_shutdown, acpi_desc); + if (rc) + return rc; + if (nfit_test->setup != nfit_test0_setup) return 0; -- 2.30.2