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Message-ID: <19f34abd0805081424v2a42d8c6t2ee795287eace3ae@mail.gmail.com>
Date: Thu, 8 May 2008 23:24:41 +0200
From: "Vegard Nossum" <vegard.nossum@...il.com>
To: "Pekka J Enberg" <penberg@...helsinki.fi>
Cc: mingo@...e.hu, clameter@....com, akpm@...ux-foundation.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] slab: add kmemcheck hooks
On Thu, May 8, 2008 at 11:03 PM, Pekka J Enberg <penberg@...helsinki.fi> wrote:
> From: Pekka Enberg <penberg@...helsinki.fi>
>
> Add kmemcheck hooks to SLAB. Note: this only works if you force SLAB to use
> compound pages manually. I didn't change SLAB to use them though as Vegard has
> a fix on the way to make kmemcheck work with non-compound pages.
>
> Cc: Ingo Molnar <mingo@...e.hu>
> Cc: Christoph Lameter <clameter@....com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Vegard Nossum <vegard.nossum@...il.com>
> Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
> ---
> arch/x86/Kconfig.debug | 2 +-
> mm/slab.c | 21 +++++++++++++++++++--
> 2 files changed, 20 insertions(+), 3 deletions(-)
>
> Index: kmemcheck/arch/x86/Kconfig.debug
> ===================================================================
> --- kmemcheck.orig/arch/x86/Kconfig.debug 2008-05-08 23:50:38.000000000 +0300
> +++ kmemcheck/arch/x86/Kconfig.debug 2008-05-08 23:50:46.000000000 +0300
> @@ -247,7 +247,7 @@
> depends on X86
> depends on !X86_USE_3DNOW
> depends on !CC_OPTIMIZE_FOR_SIZE
> - depends on !DEBUG_PAGEALLOC && SLUB
> + depends on !DEBUG_PAGEALLOC && (SLUB || SLAB)
I think it would be nicer to put
depends on SLAB || SLUB
right after the depends on X86_USE_3DNOW.
BTW, this patch should probably say X86_32 instead of X86 there.
> select FRAME_POINTER
> select STACKTRACE
> default n
> Index: kmemcheck/mm/slab.c
> ===================================================================
> --- kmemcheck.orig/mm/slab.c 2008-05-08 23:50:45.000000000 +0300
> +++ kmemcheck/mm/slab.c 2008-05-08 23:50:46.000000000 +0300
> @@ -111,6 +111,8 @@
> #include <linux/rtmutex.h>
> #include <linux/reciprocal_div.h>
> #include <linux/debugobjects.h>
> +#include <linux/kmemcheck.h>
> +#include <linux/slub_kmemcheck.h>
slab.c is probably unlikely to be changed anyway, but Andrew suggested
to insert these things not at the end, but somewhere in the middle, as
it is less likely to conflict.
>
> #include <asm/cacheflush.h>
> #include <asm/tlbflush.h>
> @@ -176,13 +178,13 @@
> SLAB_STORE_USER | \
> SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
> SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
> - SLAB_DEBUG_OBJECTS)
> + SLAB_DEBUG_OBJECTS | SLAB_NOTRACK)
> #else
> # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
> SLAB_CACHE_DMA | \
> SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
> SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
> - SLAB_DEBUG_OBJECTS)
> + SLAB_DEBUG_OBJECTS | SLAB_NOTRACK)
> #endif
>
> /*
> @@ -1611,6 +1613,10 @@
> NR_SLAB_UNRECLAIMABLE, nr_pages);
> for (i = 0; i < nr_pages; i++)
> __SetPageSlab(page + i);
> +
> + if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK))
> + kmemcheck_alloc_shadow(cachep, flags, nodeid, page, cachep->gfporder);
> +
> return page_address(page);
> }
>
> @@ -1623,6 +1629,9 @@
> struct page *page = virt_to_page(addr);
> const unsigned long nr_freed = i;
>
> + if (kmemcheck_page_is_tracked(page) && !(cachep->flags & SLAB_NOTRACK))
> + kmemcheck_free_shadow(cachep, page, cachep->gfporder);
> +
> if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
> sub_zone_page_state(page_zone(page),
> NR_SLAB_RECLAIMABLE, nr_freed);
> @@ -3337,6 +3346,9 @@
> local_irq_restore(save_flags);
> ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
>
> + if (likely(ptr))
> + kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep));
> +
> if (unlikely((flags & __GFP_ZERO) && ptr))
> memset(ptr, 0, obj_size(cachep));
>
> @@ -3391,6 +3403,9 @@
> objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
> prefetchw(objp);
>
> + if (likely(objp))
> + kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep));
> +
> if (unlikely((flags & __GFP_ZERO) && objp))
> memset(objp, 0, obj_size(cachep));
>
> @@ -3506,6 +3521,8 @@
> check_irq_off();
> objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
>
> + kmemcheck_slab_free(cachep, objp, obj_size(cachep));
> +
> /*
> * Skip calling cache_free_alien() when the platform is not numa.
> * This will avoid cache misses that happen while accessing slabp (which
>
You probably also want this:
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -27,13 +27,10 @@ obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_SLAB) += slab.o
obj-$(CONFIG_SLUB) += slub.o
+obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
obj-$(CONFIG_SMP) += allocpercpu.o
obj-$(CONFIG_QUICKLIST) += quicklist.o
obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o
-
-ifeq ($(CONFIG_KMEMCHECK),y)
-obj-$(CONFIG_SLUB) += slub_kmemcheck.o
-endif
(And put it in the middle to keep Andrew happy.)
Probably needless to say, but this is GREAT work... Such a small patch too...
Vegard
--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
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