I like it a lot.
Although I don't see much point in NBBY :-).
Couldn't you print the failing pointer on the other realloc messages? I
guess it may not be much use.
Otherwise reads fine and works for me.
On Wed, Oct 20, 2010 at 09:27:50AM +0200, Otto Moerbeek wrote:
> Hi,
>
> when feeding free(3) or realloc(3) a bogus or already free pointer, it
> helps to see the actual pointer. So here's a diff to do that.
>
> Typical output:
>
> a.out in free(): error: bogus pointer (double free?) 0x1234567890abcdef
>
> Please test & review,
>
> -Otto
>
> Index: stdlib/malloc.c
> ===================================================================
> RCS file: /cvs/src/lib/libc/stdlib/malloc.c,v
> retrieving revision 1.125
> diff -u -p -r1.125 malloc.c
> --- stdlib/malloc.c 18 May 2010 22:24:55 -0000 1.125
> +++ stdlib/malloc.c 20 Oct 2010 07:13:16 -0000
> @@ -352,12 +352,30 @@ malloc_exit(void)
> #endif /* MALLOC_STATS */
>
>
> +static void
> +ptr2str(struct iovec *io, void *p, char *buf)
> +{
> + int i, j;
> + uintptr_t n = (uintptr_t)p;
> +
> + io->iov_base = buf;
> + io->iov_len = 0;
> + if (p == NULL)
> + return;
> + buf[0] = ' ';
> + buf[1] = '0';
> + buf[2] = 'x';
> + for (j = 3, i = sizeof(n) * NBBY - NBBY/2; i >= 0; j++, i -= NBBY/2)
> + buf[j] = "0123456789abcdef"[(n >> i) & 0xf];
> + io->iov_len = j;
> +}
>
> static void
> -wrterror(char *p)
> +wrterror(char *msg, void *p)
> {
> char *q = " error: ";
> - struct iovec iov[5];
> + struct iovec iov[6];
> + char buf[20];
>
> iov[0].iov_base = __progname;
> iov[0].iov_len = strlen(__progname);
> @@ -365,11 +383,12 @@ wrterror(char *p)
> iov[1].iov_len = strlen(malloc_func);
> iov[2].iov_base = q;
> iov[2].iov_len = strlen(q);
> - iov[3].iov_base = p;
> - iov[3].iov_len = strlen(p);
> - iov[4].iov_base = "\n";
> - iov[4].iov_len = 1;
> - writev(STDERR_FILENO, iov, 5);
> + iov[3].iov_base = msg;
> + iov[3].iov_len = strlen(msg);
> + ptr2str(&iov[4], p, buf);
> + iov[5].iov_base = "\n";
> + iov[5].iov_len = 1;
> + writev(STDERR_FILENO, iov, 6);
>
> #ifdef MALLOC_STATS
> if (mopts.malloc_stats)
> @@ -414,13 +433,13 @@ unmap(struct dir_info *d, void *p, size_
> u_int i, offset;
>
> if (sz != PAGEROUND(sz)) {
> - wrterror("munmap round");
> + wrterror("munmap round", NULL);
> return;
> }
>
> if (psz > mopts.malloc_cache) {
> if (munmap(p, sz))
> - wrterror("munmap");
> + wrterror("munmap", p);
> malloc_used -= sz;
> return;
> }
> @@ -434,7 +453,7 @@ unmap(struct dir_info *d, void *p, size_
> if (r->p != NULL) {
> rsz = r->size << MALLOC_PAGESHIFT;
> if (munmap(r->p, rsz))
> - wrterror("munmap");
> + wrterror("munmap", r->p);
> r->p = NULL;
> if (tounmap > r->size)
> tounmap -= r->size;
> @@ -446,7 +465,7 @@ unmap(struct dir_info *d, void *p, size_
> }
> }
> if (tounmap > 0)
> - wrterror("malloc cache underflow");
> + wrterror("malloc cache underflow", NULL);
> for (i = 0; i < mopts.malloc_cache; i++) {
> r = &d->free_regions[i];
> if (r->p == NULL) {
> @@ -461,9 +480,9 @@ unmap(struct dir_info *d, void *p, size_
> }
> }
> if (i == mopts.malloc_cache)
> - wrterror("malloc free slot lost");
> + wrterror("malloc free slot lost", NULL);
> if (d->free_regions_size > mopts.malloc_cache)
> - wrterror("malloc cache overflow");
> + wrterror("malloc cache overflow", NULL);
> }
>
> static void
> @@ -478,7 +497,7 @@ zapcacheregion(struct dir_info *d, void
> if (r->p == p) {
> rsz = r->size << MALLOC_PAGESHIFT;
> if (munmap(r->p, rsz))
> - wrterror("munmap");
> + wrterror("munmap", r->p);
> r->p = NULL;
> d->free_regions_size -= r->size;
> r->size = 0;
> @@ -497,9 +516,9 @@ map(struct dir_info *d, size_t sz, int z
>
> if (mopts.malloc_canary != (d->canary1 ^ (u_int32_t)(uintptr_t)d) ||
> d->canary1 != ~d->canary2)
> - wrterror("internal struct corrupt");
> + wrterror("internal struct corrupt", NULL);
> if (sz != PAGEROUND(sz)) {
> - wrterror("map round");
> + wrterror("map round", NULL);
> return NULL;
> }
> if (psz > d->free_regions_size) {
> @@ -551,7 +570,7 @@ map(struct dir_info *d, size_t sz, int z
> if (p != MAP_FAILED)
> malloc_used += sz;
> if (d->free_regions_size > mopts.malloc_cache)
> - wrterror("malloc cache");
> + wrterror("malloc cache", NULL);
> /* zero fill not needed */
> return p;
> }
> @@ -724,7 +743,7 @@ omalloc_init(struct dir_info **dp)
> regioninfo_size = d->regions_total * sizeof(struct region_info);
> d->r = MMAP(regioninfo_size);
> if (d->r == MAP_FAILED) {
> - wrterror("malloc init mmap failed");
> + wrterror("malloc init mmap failed", NULL);
> d->regions_total = 0;
> return 1;
> }
> @@ -787,7 +806,7 @@ omalloc_grow(struct dir_info *d)
> }
> /* avoid pages containing meta info to end up in cache */
> if (munmap(d->r, d->regions_total * sizeof(struct region_info)))
> - wrterror("munmap");
> + wrterror("munmap", d->r);
> else
> malloc_used -= d->regions_total * sizeof(struct region_info);
> d->regions_free = d->regions_free + d->regions_total;
> @@ -853,7 +872,7 @@ find(struct dir_info *d, void *p)
>
> if (mopts.malloc_canary != (d->canary1 ^ (u_int32_t)(uintptr_t)d) ||
> d->canary1 != ~d->canary2)
> - wrterror("internal struct corrupt");
> + wrterror("internal struct corrupt", NULL);
> p = MASK_POINTER(p);
> index = hash(p) & mask;
> r = d->r[index].p;
> @@ -876,7 +895,7 @@ delete(struct dir_info *d, struct region
> size_t i, j, r;
>
> if (d->regions_total & (d->regions_total - 1))
> - wrterror("regions_total not 2^x");
> + wrterror("regions_total not 2^x", NULL);
> d->regions_free++;
> STATS_INC(g_pool->deletes);
>
> @@ -960,7 +979,7 @@ omalloc_make_chunks(struct dir_info *d,
>
> bits++;
> if ((uintptr_t)pp & bits)
> - wrterror("pp & bits");
> + wrterror("pp & bits", pp);
>
> insert(d, (void *)((uintptr_t)pp | bits), (uintptr_t)bp);
> return bp;
> @@ -980,7 +999,7 @@ malloc_bytes(struct dir_info *d, size_t
>
> if (mopts.malloc_canary != (d->canary1 ^ (u_int32_t)(uintptr_t)d) ||
> d->canary1 != ~d->canary2)
> - wrterror("internal struct corrupt");
> + wrterror("internal struct corrupt", NULL);
> /* Don't bother with anything less than this */
> /* unless we have a malloc(0) requests */
> if (size != 0 && size < MALLOC_MINSIZE)
> @@ -1005,7 +1024,7 @@ malloc_bytes(struct dir_info *d, size_t
> bp = LIST_FIRST(&d->chunk_dir[j]);
>
> if (bp->canary != d->canary1)
> - wrterror("chunk info corrupted");
> + wrterror("chunk info corrupted", NULL);
> /* Find first word of bitmap which isn't empty */
> for (lp = bp->bits; !*lp; lp++)
> /* EMPTY */;
> @@ -1029,7 +1048,7 @@ malloc_bytes(struct dir_info *d, size_t
> k = 0;
> }
> if (lp - bp->bits > (bp->total - 1) / MALLOC_BITS) {
> - wrterror("chunk overflow");
> + wrterror("chunk overflow", NULL);
> errno = EFAULT;
> return (NULL);
> }
> @@ -1065,17 +1084,17 @@ free_bytes(struct dir_info *d, struct re
>
> info = (struct chunk_info *)r->size;
> if (info->canary != d->canary1)
> - wrterror("chunk info corrupted");
> + wrterror("chunk info corrupted", NULL);
>
> /* Find the chunk number on the page */
> i = ((uintptr_t)ptr & MALLOC_PAGEMASK) >> info->shift;
>
> if ((uintptr_t)ptr & ((1UL << (info->shift)) - 1)) {
> - wrterror("modified chunk-pointer");
> + wrterror("modified chunk-pointer", ptr);
> return;
> }
> if (info->bits[i / MALLOC_BITS] & (1UL << (i % MALLOC_BITS))) {
> - wrterror("chunk is already free");
> + wrterror("chunk is already free", ptr);
> return;
> }
>
> @@ -1133,7 +1152,7 @@ omalloc(size_t sz, int zero_fill)
> if (mopts.malloc_guard) {
> if (mprotect((char *)p + psz - mopts.malloc_guard,
> mopts.malloc_guard, PROT_NONE))
> - wrterror("mprotect");
> + wrterror("mprotect", NULL);
> malloc_guarded += mopts.malloc_guard;
> }
>
> @@ -1182,7 +1201,7 @@ malloc_recurse(void)
>
> if (noprint == 0) {
> noprint = 1;
> - wrterror("recursive call");
> + wrterror("recursive call", NULL);
> }
> malloc_active--;
> _MALLOC_UNLOCK();
> @@ -1195,7 +1214,7 @@ malloc_init(void)
> if (omalloc_init(&g_pool)) {
> _MALLOC_UNLOCK();
> if (mopts.malloc_xmalloc)
> - wrterror("out of memory");
> + wrterror("out of memory", NULL);
> errno = ENOMEM;
> return -1;
> }
> @@ -1222,7 +1241,7 @@ malloc(size_t size)
> malloc_active--;
> _MALLOC_UNLOCK();
> if (r == NULL && mopts.malloc_xmalloc) {
> - wrterror("out of memory");
> + wrterror("out of memory", NULL);
> errno = ENOMEM;
> }
> if (r != NULL)
> @@ -1238,7 +1257,7 @@ ofree(void *p)
>
> r = find(g_pool, p);
> if (r == NULL) {
> - wrterror("bogus pointer (double free?)");
> + wrterror("bogus pointer (double free?)", p);
> return;
> }
> REALSIZE(sz, r);
> @@ -1246,7 +1265,7 @@ ofree(void *p)
> if (sz - mopts.malloc_guard >= MALLOC_PAGESIZE -
> MALLOC_LEEWAY) {
> if (r->p != p) {
> - wrterror("bogus pointer");
> + wrterror("bogus pointer", p);
> return;
> }
> } else {
> @@ -1261,12 +1280,12 @@ ofree(void *p)
> }
> if (mopts.malloc_guard) {
> if (sz < mopts.malloc_guard)
> - wrterror("guard size");
> + wrterror("guard size", NULL);
> if (!mopts.malloc_freeprot) {
> if (mprotect((char *)p + PAGEROUND(sz) -
> mopts.malloc_guard, mopts.malloc_guard,
> PROT_READ | PROT_WRITE))
> - wrterror("mprotect");
> + wrterror("mprotect", NULL);
> }
> malloc_guarded -= mopts.malloc_guard;
> }
> @@ -1290,7 +1309,7 @@ ofree(void *p)
> if (p != NULL) {
> r = find(g_pool, p);
> if (r == NULL) {
> - wrterror("bogus pointer (double free?)");
> + wrterror("bogus pointer (double free?)", p);
> return;
> }
> free_bytes(g_pool, r, p);
> @@ -1311,7 +1330,7 @@ free(void *ptr)
> malloc_func = " in free():";
> if (g_pool == NULL) {
> _MALLOC_UNLOCK();
> - wrterror("free() called before allocation");
> + wrterror("free() called before allocation", NULL);
> return;
> }
> if (malloc_active++) {
> @@ -1337,7 +1356,7 @@ orealloc(void *p, size_t newsz)
>
> r = find(g_pool, p);
> if (r == NULL) {
> - wrterror("bogus pointer (double free?)");
> + wrterror("bogus pointer (double free?)", p);
> return NULL;
> }
> if (newsz >= SIZE_MAX - mopts.malloc_guard - MALLOC_PAGESIZE) {
> @@ -1349,7 +1368,7 @@ orealloc(void *p, size_t newsz)
> goldsz = oldsz;
> if (oldsz > MALLOC_MAXCHUNK) {
> if (oldsz < mopts.malloc_guard)
> - wrterror("guard size");
> + wrterror("guard size", NULL);
> oldsz -= mopts.malloc_guard;
> }
>
> @@ -1383,11 +1402,11 @@ orealloc(void *p, size_t newsz)
> if (mprotect((char *)p + roldsz -
> mopts.malloc_guard, mopts.malloc_guard,
> PROT_READ | PROT_WRITE))
> - wrterror("mprotect");
> + wrterror("mprotect", NULL);
> if (mprotect((char *)p + rnewsz -
> mopts.malloc_guard, mopts.malloc_guard,
> PROT_NONE))
> - wrterror("mprotect");
> + wrterror("mprotect", NULL);
> }
> unmap(g_pool, (char *)p + rnewsz, roldsz - rnewsz);
> r->size = gnewsz;
> @@ -1437,7 +1456,7 @@ realloc(void *ptr, size_t size)
> malloc_active--;
> _MALLOC_UNLOCK();
> if (r == NULL && mopts.malloc_xmalloc) {
> - wrterror("out of memory");
> + wrterror("out of memory", NULL);
> errno = ENOMEM;
> }
> if (r != NULL)
> @@ -1464,7 +1483,7 @@ calloc(size_t nmemb, size_t size)
> nmemb > 0 && SIZE_MAX / nmemb < size) {
> _MALLOC_UNLOCK();
> if (mopts.malloc_xmalloc)
> - wrterror("out of memory");
> + wrterror("out of memory", NULL);
> errno = ENOMEM;
> return NULL;
> }
> @@ -1480,7 +1499,7 @@ calloc(size_t nmemb, size_t size)
> malloc_active--;
> _MALLOC_UNLOCK();
> if (r == NULL && mopts.malloc_xmalloc) {
> - wrterror("out of memory");
> + wrterror("out of memory", NULL);
> errno = ENOMEM;
> }
> if (r != NULL)
