Tetsuo Handa wrote:
> Hello.
>
> linux-next-20130422 does not boot when built with CONFIG_DEBUG_SLAB=y &&
> CONFIG_DEBUG_SPINLOCK=y && CONFIG_DEBUG_PAGEALLOC=y .
>
> It hangs (with CPU#0 spinning) immediately after printing
>
> Decompressing Linux... Parsing ELF... done.
> Booting the kernel.
>
> lines.
>
> Config is at http://I-love.SAKURA.ne.jp/tmp/config-3.9-rc8-next-20130422 .
>
> Any clue before starting bisection?
>
> Regards.
>
Bisection (with a build fix from commit db845067 "slab: Fixup
CONFIG_PAGE_ALLOC/DEBUG_SLAB_LEAK sections") reached commit e3366016
"slab: Use common kmalloc_index/kmalloc_size functions".
Would you have a look at commit e3366016?
By the way, I have a fear regarding commit e3366016.
include/linux/slab_def.h says
extern struct kmem_cache *kmalloc_caches[PAGE_SHIFT + MAX_ORDER];
extern struct kmem_cache *kmalloc_dma_caches[PAGE_SHIFT + MAX_ORDER];
while mm/slab.c says
struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
and include/linux/slab.h says
#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
(MAX_ORDER + PAGE_SHIFT - 1) : 25)
.
If (MAX_ORDER + PAGE_SHIFT - 1) <= 25 is true, mm/slab.c will allocate
struct kmem_cache *kmalloc_caches[MAX_ORDER + PAGE_SHIFT - 1 + 1];
struct kmem_cache *kmalloc_dma_caches[MAX_ORDER + PAGE_SHIFT - 1 + 1];
which matches the size declared in include/linux/slab_def.h .
If (MAX_ORDER + PAGE_SHIFT - 1) > 25 is true (I don't know whether such case
happens), mm/slab.c will allocate
struct kmem_cache *kmalloc_caches[25 + 1];
struct kmem_cache *kmalloc_dma_caches[25 + 1];
which is smaller than the size declared in include/linux/slab_def.h .
Well, this mismatch seems to be fixed by commit 9425c58e "slab: Common
definition for the array of kmalloc caches". But usage like
for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) {
struct kmem_cache_node *n;
struct kmem_cache *cache = kmalloc_caches[i];
is remaining.
Also, kmalloc_index() in include/linux/slab.h can return 0 to 26.
If (MAX_ORDER + PAGE_SHIFT - 1) > 25 is true and
kmalloc_index(64 * 1024 * 1024) is requested (I don't know whether such case
happens), kmalloc_caches[26] is beyond the array, for kmalloc_caches[26]
allows 0 to 25.
If (MAX_ORDER + PAGE_SHIFT - 1) <= 25 is true and
kmalloc_index(64 * 1024 * 1024) is requested (I don't know whether such case
happens), kmalloc_caches[26] is beyond the array, for
kmalloc_caches[MAX_ORDER + PAGE_SHIFT] allows 0 to MAX_ORDER + PAGE_SHIFT - 1.
Would you recheck that the array size is correct?
Regards.
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