From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S979382AbdDXX4D (ORCPT ); Mon, 24 Apr 2017 19:56:03 -0400 Received: from mga06.intel.com ([134.134.136.31]:49154 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S979360AbdDXXzt (ORCPT ); Mon, 24 Apr 2017 19:55:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.37,246,1488873600"; d="scan'208";a="91709361" Subject: [PATCH v2 1/2] libnvdimm, region: fix flush hint detection crash From: Dan Williams To: linux-nvdimm@ml01.01.org Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Date: Mon, 24 Apr 2017 16:49:56 -0700 Message-ID: <149307779612.7155.12969380677038292861.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <149307779085.7155.436029631521340565.stgit@dwillia2-desk3.amr.corp.intel.com> References: <149307779085.7155.436029631521340565.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the case where a dimm does not have any associated flush hints the ndrd->flush_wpq array may be uninitialized leading to crashes with the following signature: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: region_visible+0x10f/0x160 [libnvdimm] Call Trace: internal_create_group+0xbe/0x2f0 sysfs_create_groups+0x40/0x80 device_add+0x2d8/0x650 nd_async_device_register+0x12/0x40 [libnvdimm] async_run_entry_fn+0x39/0x170 process_one_work+0x212/0x6c0 ? process_one_work+0x197/0x6c0 worker_thread+0x4e/0x4a0 kthread+0x10c/0x140 ? process_one_work+0x6c0/0x6c0 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x31/0x40 Cc: Fixes: f284a4f23752 ("libnvdimm: introduce nvdimm_flush() and nvdimm_has_flush()") Signed-off-by: Dan Williams --- drivers/nvdimm/region_devs.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c index 8de5a04644a1..24abceda986a 100644 --- a/drivers/nvdimm/region_devs.c +++ b/drivers/nvdimm/region_devs.c @@ -1000,17 +1000,20 @@ EXPORT_SYMBOL_GPL(nvdimm_flush); */ int nvdimm_has_flush(struct nd_region *nd_region) { - struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev); int i; /* no nvdimm == flushing capability unknown */ if (nd_region->ndr_mappings == 0) return -ENXIO; - for (i = 0; i < nd_region->ndr_mappings; i++) - /* flush hints present, flushing required */ - if (ndrd_get_flush_wpq(ndrd, i, 0)) + for (i = 0; i < nd_region->ndr_mappings; i++) { + struct nd_mapping *nd_mapping = &nd_region->mapping[i]; + struct nvdimm *nvdimm = nd_mapping->nvdimm; + + /* flush hints present / available */ + if (nvdimm->num_flush) return 1; + } /* * The platform defines dimm devices without hints, assume