The patch titled
Subject: kernel/resource: fix kfree() of bootmem memory again
has been added to the -mm tree. Its filename is
kernel-resource-fix-kfree-of-bootmem-memory-again.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kernel-resource-fix-kfree-of-bootmem-memory-again.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kernel-resource-fix-kfree-of-bootmem-memory-again.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: kernel/resource: fix kfree() of bootmem memory again
Since commit ebff7d8f270d ("mem hotunplug: fix kfree() of bootmem
memory"), we could get a resource allocated during boot via
alloc_resource(). And it's required to release the resource using
free_resource(). Howerver, many people use kfree directly which will
result in kernel BUG. In order to fix this without fixing every call
site, just leak a couple of bytes in such corner case.
Link: https://lkml.kernel.org/r/20220217083619.19305-1-linmiaohe@xxxxxxxxxx
Fixes: ebff7d8f270d ("mem hotunplug: fix kfree() of bootmem memory")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/resource.c | 41 ++++++++---------------------------------
1 file changed, 8 insertions(+), 33 deletions(-)
--- a/kernel/resource.c~kernel-resource-fix-kfree-of-bootmem-memory-again
+++ a/kernel/resource.c
@@ -56,14 +56,6 @@ struct resource_constraint {
static DEFINE_RWLOCK(resource_lock);
-/*
- * For memory hotplug, there is no way to free resource entries allocated
- * by boot mem after the system is up. So for reusing the resource entry
- * we need to remember the resource.
- */
-static struct resource *bootmem_resource_free;
-static DEFINE_SPINLOCK(bootmem_resource_lock);
-
static struct resource *next_resource(struct resource *p)
{
if (p->child)
@@ -160,36 +152,19 @@ __initcall(ioresources_init);
static void free_resource(struct resource *res)
{
- if (!res)
- return;
-
- if (!PageSlab(virt_to_head_page(res))) {
- spin_lock(&bootmem_resource_lock);
- res->sibling = bootmem_resource_free;
- bootmem_resource_free = res;
- spin_unlock(&bootmem_resource_lock);
- } else {
+ /**
+ * If the resource was allocated using memblock early during boot
+ * we'll leak it here: we can only return full pages back to the
+ * buddy and trying to be smart and reusing them eventually in
+ * alloc_resource() overcomplicates resource handling.
+ */
+ if (res && PageSlab(virt_to_head_page(res)))
kfree(res);
- }
}
static struct resource *alloc_resource(gfp_t flags)
{
- struct resource *res = NULL;
-
- spin_lock(&bootmem_resource_lock);
- if (bootmem_resource_free) {
- res = bootmem_resource_free;
- bootmem_resource_free = res->sibling;
- }
- spin_unlock(&bootmem_resource_lock);
-
- if (res)
- memset(res, 0, sizeof(struct resource));
- else
- res = kzalloc(sizeof(struct resource), flags);
-
- return res;
+ return kzalloc(sizeof(struct resource), flags);
}
/* Return the conflict entry if you can't request it */
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-memremap-avoid-calling-kasan_remove_zero_shadow-for-device-private-memory.patch
filemap-remove-find_get_pages.patch
mm-use-helper-function-range_in_vma.patch
mm-sparse-make-mminit_validate_memmodel_limits-static.patch
mm-vmalloc-remove-unneeded-function-forward-declaration.patch
mm-mmzoneh-remove-unused-macros.patch
mm-memory-failurec-minor-clean-up-for-memory_failure_dev_pagemap.patch
mm-memory-failurec-catch-unexpected-efault-from-vma_address.patch
mm-memory-failurec-rework-the-signaling-logic-in-kill_proc.patch
mm-memory-failurec-fix-race-with-changing-page-more-robustly.patch
mm-memory-failurec-remove-pageslab-check-in-hwpoison_filter_dev.patch
mm-memory-failurec-rework-the-try_to_unmap-logic-in-hwpoison_user_mappings.patch
mm-memory-failurec-remove-obsolete-comment-in-__soft_offline_page.patch
mm-memory-failurec-remove-unnecessary-pagetranstail-check.patch
mm-hwpoison-inject-support-injecting-hwpoison-to-free-page.patch
mm-ksm-use-helper-macro-__attr_rw.patch
mm-balloon_compaction-make-balloon-page-compaction-callbacks-static.patch
mm-memory_hotplug-remove-obsolete-comment-of-__add_pages.patch
mm-memory_hotplug-avoid-calling-zone_intersects-for-zone_normal.patch
mm-memory_hotplug-clean-up-try_offline_node.patch
mm-memory_hotplug-fix-misplaced-comment-in-offline_pages.patch
mm-highmem-remove-unnecessary-done-label.patch
mm-hmmc-remove-unneeded-local-variable-ret.patch
kernel-resource-fix-kfree-of-bootmem-memory-again.patch
