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kernel/resource: fix kfree() of bootmem memory again 

Since commit ebff7d8f27 ("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: ebff7d8f27 ("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>
This commit is contained in:
Miaohe Lin 2022-03-23 16:07:18 -07:00 committed by Linus Torvalds
parent b3d7fe86fb
commit 0cbcc92917
1 changed files with 8 additions and 33 deletions
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41
kernel/resource.c
View File

@ -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 */