SLUB: Do not upset lockdep
inconsistent {softirq-on-W} -> {in-softirq-W} usage.
swapper/0 [HC0[0]:SC1[1]:HE0:SE0] takes:
(&n->list_lock){-+..}, at: [<ffffffff802935c1>] add_partial+0x31/0xa0
{softirq-on-W} state was registered at:
[<ffffffff80259fb8>] __lock_acquire+0x3e8/0x1140
[<ffffffff80259838>] debug_check_no_locks_freed+0x188/0x1a0
[<ffffffff8025ad65>] lock_acquire+0x55/0x70
[<ffffffff802935c1>] add_partial+0x31/0xa0
[<ffffffff805c76de>] _spin_lock+0x1e/0x30
[<ffffffff802935c1>] add_partial+0x31/0xa0
[<ffffffff80296f9c>] kmem_cache_open+0x1cc/0x330
[<ffffffff805c7984>] _spin_unlock_irq+0x24/0x30
[<ffffffff802974f4>] create_kmalloc_cache+0x64/0xf0
[<ffffffff80295640>] init_alloc_cpu_cpu+0x70/0x90
[<ffffffff8080ada5>] kmem_cache_init+0x65/0x1d0
[<ffffffff807f1b4e>] start_kernel+0x23e/0x350
[<ffffffff807f112d>] _sinittext+0x12d/0x140
[<ffffffffffffffff>] 0xffffffffffffffff
This change isn't really necessary for correctness, but it prevents lockdep
from getting upset and then disabling itself.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
diff --git a/mm/slub.c b/mm/slub.c
index a660834..3f05667 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1999,6 +1999,7 @@
{
struct page *page;
struct kmem_cache_node *n;
+ unsigned long flags;
BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
@@ -2023,7 +2024,14 @@
#endif
init_kmem_cache_node(n);
atomic_long_inc(&n->nr_slabs);
+ /*
+ * lockdep requires consistent irq usage for each lock
+ * so even though there cannot be a race this early in
+ * the boot sequence, we still disable irqs.
+ */
+ local_irq_save(flags);
add_partial(n, page, 0);
+ local_irq_restore(flags);
return n;
}