From ba84c73c7ae21fc891a3c2576fa3be42752fce53 Mon Sep 17 00:00:00 2001 From: root Date: Mon, 7 Jan 2008 23:20:28 -0800 Subject: [PATCH] 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: [] add_partial+0x31/0xa0 {softirq-on-W} state was registered at: [] __lock_acquire+0x3e8/0x1140 [] debug_check_no_locks_freed+0x188/0x1a0 [] lock_acquire+0x55/0x70 [] add_partial+0x31/0xa0 [] _spin_lock+0x1e/0x30 [] add_partial+0x31/0xa0 [] kmem_cache_open+0x1cc/0x330 [] _spin_unlock_irq+0x24/0x30 [] create_kmalloc_cache+0x64/0xf0 [] init_alloc_cpu_cpu+0x70/0x90 [] kmem_cache_init+0x65/0x1d0 [] start_kernel+0x23e/0x350 [] _sinittext+0x12d/0x140 [] 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 Cc: Christoph Lameter Cc: Kamalesh Babulal Signed-off-by: Andrew Morton Signed-off-by: Christoph Lameter --- mm/slub.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index a660834416ac..3f056677fa8f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1999,6 +1999,7 @@ static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags, { 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 @@ static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags, #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; } -- 2.20.1