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SLUB: Fix early boot GFP_DMA allocations 

Recent change to use slab allocations earlier exposed a bug where
SLUB can call schedule_work and try to call sysfs before it is
safe to do so.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
hifive-unleashed-5.1
Nick Piggin 2009-06-15 13:35:10 +03:00 committed by Pekka Enberg
parent 45e3e1935e
commit 964cf35c88
1 changed files with 14 additions and 3 deletions
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17
mm/slub.c
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@ -2610,6 +2610,7 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
struct kmem_cache *s;
char *text;
size_t realsize;
unsigned long slabflags;
s = kmalloc_caches_dma[index];
if (s)
@ -2631,9 +2632,18 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
(unsigned int)realsize);
s = kmalloc(kmem_size, flags & ~SLUB_DMA);
/*
* Must defer sysfs creation to a workqueue because we don't know
* what context we are called from. Before sysfs comes up, we don't
* need to do anything because our sysfs initcall will start by
* adding all existing slabs to sysfs.
*/
slabflags = SLAB_CACHE_DMA;
if (slab_state >= SYSFS)
slabflags |= __SYSFS_ADD_DEFERRED;
if (!s || !text || !kmem_cache_open(s, flags, text,
realsize, ARCH_KMALLOC_MINALIGN,
SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) {
realsize, ARCH_KMALLOC_MINALIGN, slabflags, NULL)) {
kfree(s);
kfree(text);
goto unlock_out;
@ -2642,7 +2652,8 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
list_add(&s->list, &slab_caches);
kmalloc_caches_dma[index] = s;
schedule_work(&sysfs_add_work);
if (slab_state >= SYSFS)
schedule_work(&sysfs_add_work);
unlock_out:
up_write(&slub_lock);