Messages in this thread Patch in this message | | | Date | Wed, 5 Jan 2011 13:16:13 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH V2] Fix handling of parse errors in sysfs |
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On Wed, 5 Jan 2011 13:16:33 -0700 Eric B Munson <emunson@mgebm.net> wrote:
> When parsing changes to the huge page pool sizes made from userspace > via the sysfs interface, bogus input values are being covered up > by nr_hugepages_store_common and nr_overcommit_hugepages_store > returning 0 when strict_strtoul returns an error. This can cause an > infinite loop in the nr_hugepages_store code. This patch changes > the return value for these functions to -EINVAL when strict_strtoul > returns an error. >
ah, OK, there we are.
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 8585524..5cb71a9 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1440,7 +1440,7 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, > > err = strict_strtoul(buf, 10, &count); > if (err) > - return 0; > + return -EINVAL; > > h = kobj_to_hstate(kobj, &nid); > if (nid == NUMA_NO_NODE) { > @@ -1519,7 +1519,7 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, > > err = strict_strtoul(buf, 10, &input); > if (err) > - return 0; > + return -EINVAL; > > spin_lock(&hugetlb_lock); > h->nr_overcommit_huge_pages = input;
strict_strtoul() returns an errno - thise code should propagate it, not overwrite it.
Here's what I ended up with:
diff -puN mm/hugetlb.c~fix-handling-of-parse-errors-in-sysfs mm/hugetlb.c --- a/mm/hugetlb.c~fix-handling-of-parse-errors-in-sysfs +++ a/mm/hugetlb.c @@ -1375,10 +1375,8 @@ static ssize_t nr_hugepages_store_common NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); err = strict_strtoul(buf, 10, &count); - if (err) { - err = 0; /* This seems wrong */ + if (err) goto out; - } h = kobj_to_hstate(kobj, &nid); if (h->order >= MAX_ORDER) { @@ -1468,7 +1466,7 @@ static ssize_t nr_overcommit_hugepages_s err = strict_strtoul(buf, 10, &input); if (err) - return 0; + return err; spin_lock(&hugetlb_lock); h->nr_overcommit_huge_pages = input; _
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