From patchwork Mon Jun 7 23:52:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 12304879 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D2FF70 for ; Mon, 7 Jun 2021 23:52:46 +0000 (UTC) IronPort-SDR: Ks+Kn3NH+WnJuhfdiAOmbMuxl9sJokeocIUf1CaIdtcI8gpWZ+2xYpKAXlEtCJ/zlXEmRYdG32 F3c/3+xkdfPw== X-IronPort-AV: E=McAfee;i="6200,9189,10008"; a="204553562" X-IronPort-AV: E=Sophos;i="5.83,256,1616482800"; d="scan'208";a="204553562" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2021 16:52:44 -0700 IronPort-SDR: +eswq4V239YUexroUSETX2OcgDXl5VgubeMsGBVUQ3UVECkD4mKgcQj5OoR5B13rK9iiRn7mcA 8hlnWFuewtmA== X-IronPort-AV: E=Sophos;i="5.83,256,1616482800"; d="scan'208";a="634889789" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.25]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2021 16:52:43 -0700 Subject: [PATCH v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage From: Dan Williams To: axboe@kernel.dk Cc: Sachin Sant , Christoph Hellwig , Ulf Hansson , nvdimm@lists.linux.dev, linux-block@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Mon, 07 Jun 2021 16:52:43 -0700 Message-ID: <162310994435.1571616.334551212901820961.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <162310861219.1571453.6561642225122047071.stgit@dwillia2-desk3.amr.corp.intel.com> References: <162310861219.1571453.6561642225122047071.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The queue_to_disk() helper can not be used after del_gendisk() communicate @disk via the pgmap->owner. Otherwise, queue_to_disk() returns NULL resulting in the splat below. Kernel attempted to read user page (330) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000330 Faulting instruction address: 0xc000000000906344 Oops: Kernel access of bad area, sig: 11 [#1] [..] NIP [c000000000906344] pmem_pagemap_cleanup+0x24/0x40 LR [c0000000004701d4] memunmap_pages+0x1b4/0x4b0 Call Trace: [c000000022cbb9c0] [c0000000009063c8] pmem_pagemap_kill+0x28/0x40 (unreliable) [c000000022cbb9e0] [c0000000004701d4] memunmap_pages+0x1b4/0x4b0 [c000000022cbba90] [c0000000008b28a0] devm_action_release+0x30/0x50 [c000000022cbbab0] [c0000000008b39c8] release_nodes+0x2f8/0x3e0 [c000000022cbbb60] [c0000000008ac440] device_release_driver_internal+0x190/0x2b0 [c000000022cbbba0] [c0000000008a8450] unbind_store+0x130/0x170 Reported-by: Sachin Sant Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk") Link: http://lore.kernel.org/r/DFB75BA8-603F-4A35-880B-C5B23EF8FA7D@linux.vnet.ibm.com Cc: Christoph Hellwig Cc: Ulf Hansson Cc: Jens Axboe Signed-off-by: Dan Williams Reviewed-by: Christoph Hellwig Tested-by: Sachin Sant --- Changes in v2 Improve the changelog. drivers/nvdimm/pmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 31f3c4bd6f72..fc6b78dd2d24 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -337,8 +337,9 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap) { struct request_queue *q = container_of(pgmap->ref, struct request_queue, q_usage_counter); + struct pmem_device *pmem = pgmap->owner; - blk_cleanup_disk(queue_to_disk(q)); + blk_cleanup_disk(pmem->disk); } static void pmem_release_queue(void *pgmap) @@ -427,6 +428,7 @@ static int pmem_attach_disk(struct device *dev, q = disk->queue; pmem->disk = disk; + pmem->pgmap.owner = pmem; pmem->pfn_flags = PFN_DEV; pmem->pgmap.ref = &q->q_usage_counter; if (is_nd_pfn(dev)) {