kmemcheck: add mm functions

PATCH In review Vegard Nossum 1 participant 1 message Jul 16, 2008

Subsystems (7)

Memory management x86 MM core Scheduler +3 more subsystems

lore

Share & tools

lore

Vegard Nossum

author

2008-07-16 00:26 UTC #0 lore raw

PATCH 10/13 kmemcheck: add mm functions

Quoted 1 line

From 11a1cb6127eb25c827468fe7c83dd92748d405b1 Mon Sep 17 00:00:00 2001

From: Vegard Nossum <[email protected]>
Date: Sat, 31 May 2008 15:56:17 +0200
Subject: [PATCH 10/13] kmemcheck: add mm functions

With kmemcheck enabled, the slab allocator needs to do this:

1. Tell kmemcheck to allocate the shadow memory which stores the status of each byte in the allocation proper, e.g. whether it is initialized or uninitialized.
2. Tell kmemcheck which parts of memory that should be marked uninitialized. There are actually a few more states, such as "not yet allocated" and "recently freed".

If a slab cache is set up using the SLAB_NOTRACK flag, it will never return memory that can take page faults because of kmemcheck.

If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still request memory with the __GFP_NOTRACK flag. This does not prevent the page faults from occuring, however, but marks the object in question as being initialized so that no warnings will ever be produced for this object.

Parts of this patch were contributed by Pekka Enberg but merged for atomicity.

Signed-off-by Vegard Nossum <[email protected]>

---
 arch/x86/kernel/process.c |    2 +-
 include/linux/gfp.h       |    3 +-
 include/linux/kmemcheck.h |   48 ++++++++++++++++++++++
 include/linux/slab.h      |    7 +++
 kernel/fork.c             |   16 ++++----
 mm/Makefile               |    2 +-
 mm/kmemcheck.c            |   97 +++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 164 insertions(+), 11 deletions(-)
 create mode 100644 mm/kmemcheck.c

arch/x86/kernel/process.c +1 -1

index ba370dc..d61d452 100644
@@ -42,7 +42,7 @@ void arch_task_cache_init(void)
         task_xstate_cachep =
         	kmem_cache_create("task_xstate", xstate_size,
 				  __alignof__(union thread_xstate),
-				  SLAB_PANIC, NULL);
+				  SLAB_PANIC | SLAB_NOTRACK, NULL);
 }
 
 static void do_nothing(void *unused)

include/linux/gfp.h +2 -1

index b414be3..7c1db87 100644
@@ -50,8 +50,9 @@ struct vm_area_struct;
 #define __GFP_THISNODE	((__force gfp_t)0x40000u)/* No fallback, no policies */
 #define __GFP_RECLAIMABLE ((__force gfp_t)0x80000u) /* Page is reclaimable */
 #define __GFP_MOVABLE	((__force gfp_t)0x100000u)  /* Page is movable */
+#define __GFP_NOTRACK	((__force gfp_t)0x200000u)  /* Don't track with kmemcheck */
 
-#define __GFP_BITS_SHIFT 21	/* Room for 21 __GFP_FOO bits */
+#define __GFP_BITS_SHIFT 22	/* Room for 22 __GFP_FOO bits */
 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
 
 /* This equals 0, but use constants in case they ever change */

include/linux/kmemcheck.h +48 -0

60 lines not on this page · raw message

include/linux/slab.h +7 -0

index 9aa90a6..faff12b 100644
@@ -34,6 +34,13 @@
 # define SLAB_DEBUG_OBJECTS	0x00000000UL
 #endif
 
+/* Don't track use of uninitialized memory */
+#ifdef CONFIG_KMEMCHECK
+# define SLAB_NOTRACK		0x00800000UL
+#else
+# define SLAB_NOTRACK		0x00000000UL
+#endif
+
 /* The following flags affect the page allocator grouping pages by mobility */
 #define SLAB_RECLAIM_ACCOUNT	0x00020000UL		/* Objects are reclaimable */
 #define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */

kernel/fork.c +8 -8

index 19908b2..25c2aa3 100644
@@ -150,7 +150,7 @@ void __init fork_init(unsigned long mempages)
 	/* create a slab on which task_structs can be allocated */
 	task_struct_cachep =
 		kmem_cache_create("task_struct", sizeof(struct task_struct),
-			ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL);
+			ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL);
 #endif
 
 	/* do the arch specific task caches init */

@@ -1415,23 +1415,23 @@ void __init proc_caches_init(void)
 {
 	sighand_cachep = kmem_cache_create("sighand_cache",
 			sizeof(struct sighand_struct), 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU,
-			sighand_ctor);
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU|
+			SLAB_NOTRACK, sighand_ctor);
 	signal_cachep = kmem_cache_create("signal_cache",
 			sizeof(struct signal_struct), 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
 	files_cachep = kmem_cache_create("files_cache",
 			sizeof(struct files_struct), 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
 	fs_cachep = kmem_cache_create("fs_cache",
 			sizeof(struct fs_struct), 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
 	vm_area_cachep = kmem_cache_create("vm_area_struct",
 			sizeof(struct vm_area_struct), 0,
-			SLAB_PANIC, NULL);
+			SLAB_PANIC|SLAB_NOTRACK, NULL);
 	mm_cachep = kmem_cache_create("mm_struct",
 			sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
 }
 
 /*

mm/Makefile +1 -1

index 18c143b..4801918 100644
@@ -27,10 +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
-

mm/kmemcheck.c new file +97 -0

97 lines not on this page · raw message

Signature · 1 line

1.5.5.1