Patch "mm: Fix devm_memremap_pages() collision handling" has been added to the 4.9-stable tree

Patch "mm: Fix devm_memremap_pages() collision handling" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mm: Fix devm_memremap_pages() collision handling

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mm-fix-devm_memremap_pages-collision-handling.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Feb 26 20:55:53 CET 2018
From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 23 Feb 2018 14:06:10 -0800
Subject: mm: Fix devm_memremap_pages() collision handling
To: gregkh@linuxfoundation.org
Cc: 
Message-ID: <151942357089.21775.3486425046348885247.stgit@dwillia2-desk3.amr.corp.intel.com>

From: Jan H. Schönherr <jschoenh@amazon.de>

commit 77dd66a3c67c93ab401ccc15efff25578be281fd upstream.

If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.

Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.

Cc: <stable@vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/memremap.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -194,7 +194,7 @@ void put_zone_device_page(struct page *p
 }
 EXPORT_SYMBOL(put_zone_device_page);
 
-static void pgmap_radix_release(struct resource *res)
+static void pgmap_radix_release(struct resource *res, resource_size_t end_key)
 {
 	resource_size_t key, align_start, align_size, align_end;
 
@@ -203,8 +203,11 @@ static void pgmap_radix_release(struct r
 	align_end = align_start + align_size - 1;
 
 	mutex_lock(&pgmap_lock);
-	for (key = res->start; key <= res->end; key += SECTION_SIZE)
+	for (key = res->start; key <= res->end; key += SECTION_SIZE) {
+		if (key >= end_key)
+			break;
 		radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT);
+	}
 	mutex_unlock(&pgmap_lock);
 }
 
@@ -255,7 +258,7 @@ static void devm_memremap_pages_release(
 	unlock_device_hotplug();
 
 	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
-	pgmap_radix_release(res);
+	pgmap_radix_release(res, -1);
 	dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
 			"%s: failed to free all reserved pages\n", __func__);
 }
@@ -289,7 +292,7 @@ struct dev_pagemap *find_dev_pagemap(res
 void *devm_memremap_pages(struct device *dev, struct resource *res,
 		struct percpu_ref *ref, struct vmem_altmap *altmap)
 {
-	resource_size_t key, align_start, align_size, align_end;
+	resource_size_t key = 0, align_start, align_size, align_end;
 	pgprot_t pgprot = PAGE_KERNEL;
 	struct dev_pagemap *pgmap;
 	struct page_map *page_map;
@@ -392,7 +395,7 @@ void *devm_memremap_pages(struct device
 	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
  err_pfn_remap:
  err_radix:
-	pgmap_radix_release(res);
+	pgmap_radix_release(res, key);
 	devres_free(page_map);
 	return ERR_PTR(error);
 }


Patches currently in stable-queue which might be from dan.j.williams@intel.com are

queue-4.9/mm-fix-devm_memremap_pages-collision-handling.patch
queue-4.9/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch
queue-4.9/mm-avoid-spurious-bad-pmd-warning-messages.patch
queue-4.9/mm-introduce-get_user_pages_longterm.patch
queue-4.9/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch
queue-4.9/fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
queue-4.9/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch
queue-4.9/v4l2-disable-filesystem-dax-mapping-support.patch
queue-4.9/libnvdimm-dax-fix-1gb-aligned-namespaces-vs-physical-misalignment.patch
queue-4.9/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch
queue-4.9/libnvdimm-fix-integer-overflow-static-analysis-warning.patch