i386 uses kmalloc to allocate the threadinfo structure assuming that the allocations result in a page sized aligned allocation. That has worked so far because SLAB exempts page sized slabs from debugging and aligns them in special ways that goes beyond the restrictions imposed by KMALLOC_ARCH_MINALIGN valid for other slabs in the kmalloc array.
SLUB also works fine without debugging since page sized allocations neatly align at page boundaries. However, if debugging is switched on then SLUB will extend the slab with debug information. The resulting slab is not longer of page size. It will only be aligned following the requirements imposed by KMALLOC_ARCH_MINALIGN. As a result the threadinfo structure may not be page aligned which makes i386 fail to boot with SLUB debug on. Replace the calls to kmalloc with calls into the page allocator. An alternate solution may be to create a custom slab cache where the alignment is set to PAGE_SIZE. That would allow slub debugging to be applied to the threadinfo structure. Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]> Index: linux-2.6.21-rc5-mm4/include/asm-i386/thread_info.h =================================================================== --- linux-2.6.21-rc5-mm4.orig/include/asm-i386/thread_info.h 2007-04-03 23:48:34.000000000 -0700 +++ linux-2.6.21-rc5-mm4/include/asm-i386/thread_info.h 2007-04-04 17:33:41.000000000 -0700 @@ -95,12 +95,14 @@ static inline struct thread_info *curren /* thread information allocation */ #ifdef CONFIG_DEBUG_STACK_USAGE -#define alloc_thread_info(tsk) kzalloc(THREAD_SIZE, GFP_KERNEL) +#define alloc_thread_info(tsk) ((struct thread_info *) \ + __get_free_pages(GFP_KERNEL| __GFP_ZERO, get_order(THREAD_SIZE))) #else -#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL) +#define alloc_thread_info(tsk) ((struct thread_info *) \ + __get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE))) #endif -#define free_thread_info(info) kfree(info) +#define free_thread_info(info) free_pages((unsigned long)(info), get_order(THREAD_SIZE)) #else /* !__ASSEMBLY__ */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
