From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 33B8B6B0003 for ; Thu, 14 Jun 2018 14:25:06 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id g20-v6so3379763pfi.2 for ; Thu, 14 Jun 2018 11:25:06 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id v11-v6si5947014plp.25.2018.06.14.11.25.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Jun 2018 11:25:04 -0700 (PDT) Subject: [PATCH] mm: disallow mapping that conflict for devm_memremap_pages() From: Dave Jiang Date: Thu, 14 Jun 2018 11:25:03 -0700 Message-ID: <152900070339.49084.2958083852988708457.stgit@djiang5-desk3.ch.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, dan.j.williams@intel.com, linux-nvdimm@lists.01.org When pmem namespaces created are smaller than section size, this can cause issue during removal and gpf was observed: [ 249.613597] general protection fault: 0000 1 SMP PTI [ 249.725203] CPU: 36 PID: 3941 Comm: ndctl Tainted: G W 4.14.28-1.el7uek.x86_64 #2 [ 249.745495] task: ffff88acda150000 task.stack: ffffc900233a4000 [ 249.752107] RIP: 0010:__put_page+0x56/0x79 [ 249.844675] Call Trace: [ 249.847410] devm_memremap_pages_release+0x155/0x23a [ 249.852953] release_nodes+0x21e/0x260 [ 249.857138] devres_release_all+0x3c/0x48 [ 249.861606] device_release_driver_internal+0x15c/0x207 [ 249.867439] device_release_driver+0x12/0x14 [ 249.872204] unbind_store+0xba/0xd8 [ 249.876098] drv_attr_store+0x27/0x31 [ 249.880186] sysfs_kf_write+0x3f/0x46 [ 249.884266] kernfs_fop_write+0x10f/0x18b [ 249.888734] __vfs_write+0x3a/0x16d [ 249.892628] ? selinux_file_permission+0xe5/0x116 [ 249.897881] ? security_file_permission+0x41/0xbb [ 249.903133] vfs_write+0xb2/0x1a1 [ 249.906835] ? syscall_trace_enter+0x1ce/0x2b8 [ 249.911795] SyS_write+0x55/0xb9 [ 249.915397] do_syscall_64+0x79/0x1ae [ 249.919485] entry_SYSCALL_64_after_hwframe+0x3d/0x0 Add code to check whether we have mapping already in the same section and prevent additional mapping from created if that is the case. Signed-off-by: Dave Jiang --- kernel/memremap.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/kernel/memremap.c b/kernel/memremap.c index 5857267a4af5..d9ac547993cb 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -176,10 +176,27 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) unsigned long pfn, pgoff, order; pgprot_t pgprot = PAGE_KERNEL; int error, nid, is_ram; + struct dev_pagemap *conflict_pgmap; align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) - align_start; + align_end = align_start + align_size - 1; + + conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL); + if (conflict_pgmap) { + dev_warn(dev, "Conflicting mapping in same section\n"); + put_dev_pagemap(conflict_pgmap); + return ERR_PTR(-ENOMEM); + } + + conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL); + if (conflict_pgmap) { + dev_warn(dev, "Conflicting mapping in same section\n"); + put_dev_pagemap(conflict_pgmap); + return ERR_PTR(-ENOMEM); + } + is_ram = region_intersects(align_start, align_size, IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); @@ -199,7 +216,6 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) mutex_lock(&pgmap_lock); error = 0; - align_end = align_start + align_size - 1; foreach_order_pgoff(res, order, pgoff) { error = __radix_tree_insert(&pgmap_radix,