[PATCH] fix potential stack overflow in mm/slab.c
On High end systems (1024 or so cpus) this can potentially cause stack
overflow. Fix the stack usage.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/slab.c b/mm/slab.c
index 2b37a62..619337a 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3725,22 +3725,26 @@
static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
int batchcount, int shared)
{
- struct ccupdate_struct new;
+ struct ccupdate_struct *new;
int i;
- memset(&new.new, 0, sizeof(new.new));
+ new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+
for_each_online_cpu(i) {
- new.new[i] = alloc_arraycache(cpu_to_node(i), limit,
+ new->new[i] = alloc_arraycache(cpu_to_node(i), limit,
batchcount);
- if (!new.new[i]) {
+ if (!new->new[i]) {
for (i--; i >= 0; i--)
- kfree(new.new[i]);
+ kfree(new->new[i]);
+ kfree(new);
return -ENOMEM;
}
}
- new.cachep = cachep;
+ new->cachep = cachep;
- on_each_cpu(do_ccupdate_local, (void *)&new, 1, 1);
+ on_each_cpu(do_ccupdate_local, (void *)new, 1, 1);
check_irq_on();
cachep->batchcount = batchcount;
@@ -3748,7 +3752,7 @@
cachep->shared = shared;
for_each_online_cpu(i) {
- struct array_cache *ccold = new.new[i];
+ struct array_cache *ccold = new->new[i];
if (!ccold)
continue;
spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
@@ -3756,7 +3760,7 @@
spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
kfree(ccold);
}
-
+ kfree(new);
return alloc_kmemlist(cachep);
}
@@ -4274,6 +4278,7 @@
show_symbol(m, n[2*i+2]);
seq_putc(m, '\n');
}
+
return 0;
}