2012/7/8 Fengguang Wu <fengguang.wu@xxxxxxxxx>:
> Hi Vegard,
>
> This warning code is triggered for the attached config:
>
> __lockdep_trace_alloc():
> /*
> * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
> */
> if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
> return;
>
> Where the irq is possibly disabled at the beginning of __slab_alloc():
>
> local_irq_save(flags);
Currently, in slub code, kmemcheck_alloc_shadow is always invoked with
irq_disabled.
I think that something like below is needed.
diff --git a/mm/slub.c b/mm/slub.c
index 8c691fa..5d41cad 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1324,8 +1324,14 @@ static struct page *allocate_slab(struct
kmem_cache *s, gfp_t flags, int node)
&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
int pages = 1 << oo_order(oo);
+ if (flags & __GFP_WAIT)
+ local_irq_enable();
+
kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
+ if (flags & __GFP_WAIT)
+ local_irq_disable();
+
/*
* Objects from caches that have a constructor don't get
* cleared when they're allocated, so we need to do it here.
--
1.7.0.4
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