diff options
| author | Miaohe Lin <linmiaohe@huawei.com> | 2022-03-23 16:07:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-23 19:00:35 -0700 |
| commit | 0cbcc92917c5de80f15c24d033566539ad696892 (patch) | |
| tree | 380d8f619508d02bf01eeeaf818fc3a9c208a531 | |
| parent | b3d7fe86fbd06638c71dd851ba921adf50d912ce (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>
| -rw-r--r-- | kernel/resource.c | 41 |
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 */ |