From c601fd6956e92b0eb268d4af754073c76155b99d Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 5 Feb 2013 16:36:47 +0000 Subject: [PATCH] slab: Handle ARCH_DMA_MINALIGN correctly James Hogan hit boot problems in next-20130204 on Meta: META213-Thread0 DSP [LogF] kobject (4fc03980): tried to init an initialized object, something is seriously wrong. META213-Thread0 DSP [LogF] META213-Thread0 DSP [LogF] Call trace: META213-Thread0 DSP [LogF] [<4000888c>] _show_stack+0x68/0x7c META213-Thread0 DSP [LogF] [<400088b4>] _dump_stack+0x14/0x28 META213-Thread0 DSP [LogF] [<40103794>] _kobject_init+0x58/0x9c META213-Thread0 DSP [LogF] [<40103810>] _kobject_create+0x38/0x64 META213-Thread0 DSP [LogF] [<40103eac>] _kobject_create_and_add+0x14/0x8c META213-Thread0 DSP [LogF] [<40190ac4>] _mnt_init+0xd8/0x220 META213-Thread0 DSP [LogF] [<40190508>] _vfs_caches_init+0xb0/0x160 META213-Thread0 DSP [LogF] [<401851f4>] _start_kernel+0x274/0x340 META213-Thread0 DSP [LogF] [<40188424>] _metag_start_kernel+0x58/0x6c META213-Thread0 DSP [LogF] [<40000044>] __start+0x44/0x48 META213-Thread0 DSP [LogF] META213-Thread0 DSP [LogF] devtmpfs: initialized META213-Thread0 DSP [LogF] L2 Cache: Not present META213-Thread0 DSP [LogF] BUG: failure at fs/sysfs/dir.c:736/sysfs_read_ns_type()! META213-Thread0 DSP [LogF] Kernel panic - not syncing: BUG! META213-Thread0 DSP [Thread Exit] Thread has exited - return code = 4294967295 And bisected the problem to commit 95a05b4 ("slab: Common constants for kmalloc boundaries"). As it turns out, a fixed KMALLOC_SHIFT_LOW does not work for arches with higher alignment requirements. Determine KMALLOC_SHIFT_LOW from ARCH_DMA_MINALIGN instead. Reported-and-tested-by: James Hogan Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- include/linux/slab.h | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index f2327a898a85..0c621752caa6 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -133,6 +133,19 @@ void kfree(const void *); void kzfree(const void *); size_t ksize(const void *); +/* + * Some archs want to perform DMA into kmalloc caches and need a guaranteed + * alignment larger than the alignment of a 64-bit integer. + * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that. + */ +#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 +#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN +#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN +#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN) +#else +#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) +#endif + #ifdef CONFIG_SLOB /* * Common fields provided in kmem_cache by all slab allocators @@ -179,7 +192,9 @@ struct kmem_cache { #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \ (MAX_ORDER + PAGE_SHIFT - 1) : 25) #define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH +#ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 5 +#endif #else /* * SLUB allocates up to order 2 pages directly and otherwise @@ -187,8 +202,10 @@ struct kmem_cache { */ #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT) +#ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 3 #endif +#endif /* Maximum allocatable size */ #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) @@ -200,9 +217,7 @@ struct kmem_cache { /* * Kmalloc subsystem. */ -#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 -#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN -#else +#ifndef KMALLOC_MIN_SIZE #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) #endif @@ -289,17 +304,6 @@ static __always_inline int kmalloc_size(int n) } #endif /* !CONFIG_SLOB */ -/* - * Some archs want to perform DMA into kmalloc caches and need a guaranteed - * alignment larger than the alignment of a 64-bit integer. - * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that. - */ -#ifdef ARCH_DMA_MINALIGN -#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN -#else -#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) -#endif - /* * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. * Intended for arches that get misalignment faults even for 64 bit integer -- 2.20.1