The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 77dd66a3c67c93ab401ccc15efff25578be281fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= jschoenh@amazon.de Date: Fri, 19 Jan 2018 16:26:33 -0800 Subject: [PATCH] mm: Fix devm_memremap_pages() collision handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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
diff --git a/kernel/memremap.c b/kernel/memremap.c index 4ef97525a4ff..4849be5f9b3c 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -241,13 +241,16 @@ int device_private_entry_fault(struct vm_area_struct *vma, EXPORT_SYMBOL(device_private_entry_fault); #endif /* CONFIG_DEVICE_PRIVATE */
-static void pgmap_radix_release(struct resource *res) +static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff) { unsigned long pgoff, order;
mutex_lock(&pgmap_lock); - foreach_order_pgoff(res, order, pgoff) + foreach_order_pgoff(res, order, pgoff) { + if (pgoff >= end_pgoff) + break; radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff); + } mutex_unlock(&pgmap_lock);
synchronize_rcu(); @@ -302,7 +305,7 @@ static void devm_memremap_pages_release(void *data) mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size); - pgmap_radix_release(res); + pgmap_radix_release(res, -1); dev_WARN_ONCE(dev, pgmap->altmap.alloc, "%s: failed to free all reserved pages\n", __func__); } @@ -418,7 +421,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) untrack_pfn(NULL, PHYS_PFN(align_start), align_size); err_pfn_remap: err_radix: - pgmap_radix_release(res); + pgmap_radix_release(res, pgoff); devres_free(pgmap); return ERR_PTR(error); }