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Extend the information that MALLOCLOG outputs to include the preceding 

buffer.  This can be helpful in the case where a buffer overrun in the
preceding region stomps on the following regions data.
This commit is contained in:
blymn 2008-10-26 12:23:28 +00:00
parent 49169f6211
commit 811c38a41c
1 changed files with 42 additions and 5 deletions
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47
sys/kern/kern_malloc.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_malloc.c,v 1.120 2008/09/25 16:23:45 pooka Exp $ */
/* $NetBSD: kern_malloc.c,v 1.121 2008/10/26 12:23:28 blymn Exp $ */
/*
* Copyright (c) 1987, 1991, 1993
@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_malloc.c,v 1.120 2008/09/25 16:23:45 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_malloc.c,v 1.121 2008/10/26 12:23:28 blymn Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@ -192,6 +192,13 @@ struct malloclog {
long malloclogptr;
/*
* Fuzz factor for neighbour address match this must be a mask of the lower
* bits we wish to ignore when comparing addresses
*/
__uintptr_t malloclog_fuzz = 0x7FL;
static void
domlog(void *a, long size, struct malloc_type *type, int action,
const char *file, long line)
@ -227,11 +234,41 @@ hitmlog(void *a)
} \
} while (/* CONSTCOND */0)
for (l = malloclogptr; l < MALLOCLOGSIZE; l++)
PRT;
/*
* Print fuzzy matched "neighbour" - look for the memory block that has
* been allocated below the address we are interested in. We look for a
* base address + size that is within malloclog_fuzz of our target
* address. If the base address and target address are the same then it is
* likely we have found a free (size is 0 in this case) so we won't report
* those, they will get reported by PRT anyway.
*/
#define NPRT do { \
__uintptr_t fuzz_mask = ~(malloclog_fuzz); \
lp = &malloclog[l]; \
if ((__uintptr_t)lp->addr != (__uintptr_t)a && \
(((__uintptr_t)lp->addr + lp->size + malloclog_fuzz) & fuzz_mask) \
== ((__uintptr_t)a & fuzz_mask) && lp->action) { \
printf("neighbour malloc log entry %ld:\n", l); \
printf("\taddr = %p\n", lp->addr); \
printf("\tsize = %ld\n", lp->size); \
printf("\ttype = %s\n", lp->type->ks_shortdesc); \
printf("\taction = %s\n", lp->action == 1 ? "alloc" : "free"); \
printf("\tfile = %s\n", lp->file); \
printf("\tline = %ld\n", lp->line); \
} \
} while (/* CONSTCOND */0)
for (l = 0; l < malloclogptr; l++)
for (l = malloclogptr; l < MALLOCLOGSIZE; l++) {
PRT;
NPRT;
}
for (l = 0; l < malloclogptr; l++) {
PRT;
NPRT;
}
#undef PRT
}
#endif /* MALLOCLOG */