From adbe8726dc2a3805630d517270db17e3af86e526 Mon Sep 17 00:00:00 2001 From: Eric B Munson Date: Thu, 13 Jan 2011 15:47:27 -0800 Subject: [PATCH] hugetlb: do not allow pagesize >= MAX_ORDER pool adjustment Huge pages with order >= MAX_ORDER must be allocated at boot via the kernel command line, they cannot be allocated or freed once the kernel is up and running. Currently we allow values to be written to the sysfs and sysctl files controling pool size for these huge page sizes. This patch makes the store functions for nr_hugepages and nr_overcommit_hugepages return -EINVAL when the pool for a page size >= MAX_ORDER is changed. [akpm@linux-foundation.org: avoid multiple return paths in nr_hugepages_store_common()] [caiqian@redhat.com: add checking in hugetlb_overcommit_handler()] Signed-off-by: Eric B Munson Reported-by: CAI Qian Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Nishanth Aravamudan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 363c4d22602a..ce8e5bb6f031 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1363,6 +1363,7 @@ static ssize_t nr_hugepages_show_common(struct kobject *kobj, return sprintf(buf, "%lu\n", nr_huge_pages); } + static ssize_t nr_hugepages_store_common(bool obey_mempolicy, struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) @@ -1375,11 +1376,16 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, err = strict_strtoul(buf, 10, &count); if (err) { - NODEMASK_FREE(nodes_allowed); - return 0; + err = 0; /* This seems wrong */ + goto out; } h = kobj_to_hstate(kobj, &nid); + if (h->order >= MAX_ORDER) { + err = -EINVAL; + goto out; + } + if (nid == NUMA_NO_NODE) { /* * global hstate attribute @@ -1405,6 +1411,9 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, NODEMASK_FREE(nodes_allowed); return len; +out: + NODEMASK_FREE(nodes_allowed); + return err; } static ssize_t nr_hugepages_show(struct kobject *kobj, @@ -1447,6 +1456,7 @@ static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, struct hstate *h = kobj_to_hstate(kobj, NULL); return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); } + static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { @@ -1454,6 +1464,9 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, unsigned long input; struct hstate *h = kobj_to_hstate(kobj, NULL); + if (h->order >= MAX_ORDER) + return -EINVAL; + err = strict_strtoul(buf, 10, &input); if (err) return 0; @@ -1864,6 +1877,9 @@ static int hugetlb_sysctl_handler_common(bool obey_mempolicy, if (!write) tmp = h->max_huge_pages; + if (write && h->order >= MAX_ORDER) + return -EINVAL; + table->data = &tmp; table->maxlen = sizeof(unsigned long); ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); @@ -1927,6 +1943,9 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write, if (!write) tmp = h->nr_overcommit_huge_pages; + if (write && h->order >= MAX_ORDER) + return -EINVAL; + table->data = &tmp; table->maxlen = sizeof(unsigned long); ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);