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1) Make clear that we want the space allocated for the KMEM_SIZE header to be

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aligned, by using kmem_roundup_size(). There's no functional difference with
   the current MAX().

2) If there isn't enough space in the page padding for the red zone, allocate
   one more page, not just 2 bytes. We only poison 1 or 2 bytes in this page,
   depending on the space left in the previous page. That way 'allocsz' is
   properly aligned. Again, there's no functional difference since the shift
   already handles it correctly.
This commit is contained in:
maxv 2014-06-25 16:35:12 +00:00
parent bf8fee7bf6
commit 5b91db99c9
1 changed files with 7 additions and 7 deletions
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14
sys/kern/subr_kmem.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $ */
/* $NetBSD: subr_kmem.c,v 1.56 2014/06/25 16:35:12 maxv Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -69,7 +69,7 @@
/*
* KMEM_REDZONE: detect overrun bugs.
* Add a 2-byte pattern (allocate some more bytes if needed) at the end
* Add a 2-byte pattern (allocate one more page if needed) at the end
* of each allocated buffer. Check this pattern on kmem_free.
*
* KMEM_POISON: detect modify-after-free bugs.
@ -90,7 +90,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.56 2014/06/25 16:35:12 maxv Exp $");
#include <sys/param.h>
#include <sys/callback.h>
@ -196,7 +196,7 @@ static void kmem_redzone_check(void *p, size_t sz);
#endif /* defined(KMEM_REDZONE) */
#if defined(KMEM_SIZE)
#define SIZE_SIZE (MAX(KMEM_ALIGN, sizeof(size_t)))
#define SIZE_SIZE kmem_roundup_size(sizeof(size_t))
static void kmem_size_set(void *, size_t);
static void kmem_size_check(void *, size_t);
#else
@ -244,8 +244,8 @@ kmem_intr_alloc(size_t requested_size, km_flag_t kmflags)
#ifdef KMEM_REDZONE
if (size - requested_size < REDZONE_SIZE) {
/* If there isn't enough space in the page padding,
* allocate two more bytes for the red zone. */
allocsz += REDZONE_SIZE;
* allocate one more page for the red zone. */
allocsz += kmem_roundup_size(REDZONE_SIZE);
}
#endif
@ -322,7 +322,7 @@ kmem_intr_free(void *p, size_t requested_size)
#ifdef KMEM_REDZONE
if (size - requested_size < REDZONE_SIZE) {
allocsz += REDZONE_SIZE;
allocsz += kmem_roundup_size(REDZONE_SIZE);
}
#endif