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authorMiaohe Lin <linmiaohe@huawei.com>2022-03-23 16:07:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-23 19:00:35 -0700
commit0cbcc92917c5de80f15c24d033566539ad696892 (patch)
tree380d8f619508d02bf01eeeaf818fc3a9c208a531 /kernel
parentb3d7fe86fbd06638c71dd851ba921adf50d912ce (diff)
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@huawei.com Fixes: ebff7d8f270d ("mem hotunplug: fix kfree() of bootmem memory") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Suggested-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Alistair Popple <apopple@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/resource.c41
1 files changed, 8 insertions, 33 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index 9c08d6e9eef2..34eaee179689 100644
--- a/kernel/resource.c
+++ b/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 */