Hi.
Recently I twisted the xen xm dump-core format so that the section
order was changed for optimization.
Although it shouldn't affect analysis tools, it revealed a bug.
The crash utility tries to read the file beyond EOF.
So far it wasn't issue because of section ordering.
This patch fixes it by calculating read size correctly
Dave,
Although I don't think that it causes serious issues,
Could you check whether the minor update of the format affects
the crash utility?
http://article.gmane.org/gmane.comp.emulators.xen.ia64/7531
http://article.gmane.org/gmane.comp.emulators.xen.devel/42996
--- crash-4.0-4.6-ORIG/xendump.c 2007-08-28 00:51:11.000000000 +0900
+++ ./crash-4.0-4.6/xendump.c 2007-08-29 18:14:05.000000000 +0900
@@ -1289,9 +1289,8 @@ xc_core_mfn_to_page(ulong mfn, char *pgb
for (b = 0, idx = -1, done = FALSE;
!done && (b < nr_pages); b += MAX_BATCH_SIZE) {
-
- if (read(xd->xfd, tmp, sizeof(ulong) * MAX_BATCH_SIZE) !=
- (MAX_BATCH_SIZE * sizeof(ulong))) {
+ size_t size = sizeof(ulong) * MIN(MAX_BATCH_SIZE, nr_pages - b);
+ if (read(xd->xfd, tmp, size) != size) {
error(INFO, "cannot read index page %d\n", b);
return NULL;
}
@@ -1348,13 +1347,11 @@ xc_core_elf_mfn_to_page(ulong mfn, char
{
int i, b, idx, done;
off_t offset;
- size_t size;
uint nr_pages;
ulong tmp;
struct xen_dumpcore_p2m p2m_batch[MAX_BATCH_SIZE];
offset = xd->xc_core.header.xch_index_offset;
- size = sizeof(struct xen_dumpcore_p2m) * MAX_BATCH_SIZE;
nr_pages = xd->xc_core.header.xch_nr_pages;
if (lseek(xd->xfd, offset, SEEK_SET) == -1)
@@ -1362,7 +1359,8 @@ xc_core_elf_mfn_to_page(ulong mfn, char
for (b = 0, idx = -1, done = FALSE;
!done && (b < nr_pages); b += MAX_BATCH_SIZE) {
-
+ size_t size = sizeof(struct xen_dumpcore_p2m) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
if (read(xd->xfd, &p2m_batch[0], size) != size) {
error(INFO, "cannot read index page %d\n", b);
return NULL;
@@ -1437,9 +1435,9 @@ xc_core_mfn_to_page_index(ulong mfn)
nr_pages *= 2;
for (b = 0; b < nr_pages; b += MAX_BATCH_SIZE) {
-
- if (read(xd->xfd, tmp, sizeof(ulong) * MAX_BATCH_SIZE) !=
- (MAX_BATCH_SIZE * sizeof(ulong))) {
+ size_t size =
+ sizeof(ulong) * MIN(MAX_BATCH_SIZE, nr_pages - b);
+ if (read(xd->xfd, tmp, size) != size) {
error(INFO, "cannot read index page %d\n", b);
return MFN_NOT_FOUND;
}
@@ -1469,20 +1467,19 @@ xc_core_elf_mfn_to_page_index(ulong mfn)
{
int i, b;
off_t offset;
- size_t size;
uint nr_pages;
ulong tmp;
struct xen_dumpcore_p2m p2m_batch[MAX_BATCH_SIZE];
offset = xd->xc_core.header.xch_index_offset;
- size = sizeof(struct xen_dumpcore_p2m) * MAX_BATCH_SIZE;
nr_pages = xd->xc_core.header.xch_nr_pages;
if (lseek(xd->xfd, offset, SEEK_SET) == -1)
error(FATAL, "cannot lseek to page index\n");
for (b = 0; b < nr_pages; b += MAX_BATCH_SIZE) {
-
+ size_t size = sizeof(struct xen_dumpcore_p2m) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
if (read(xd->xfd, &p2m_batch[0], size) != size) {
error(INFO, "cannot read index page %d\n", b);
return MFN_NOT_FOUND;
@@ -1563,8 +1560,9 @@ check_next_4:
nr_pages = xd->xc_core.header.xch_nr_pages;
for (b = 0; b < nr_pages; b += MAX_BATCH_SIZE) {
- if (read(xd->xfd, tmp, sizeof(ulong) * MAX_BATCH_SIZE)
!=
- (MAX_BATCH_SIZE * sizeof(ulong))) {
+ size_t size = sizeof(ulong) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
+ if (read(xd->xfd, tmp, size) != size) {
error(INFO, "cannot read index page %d\n", b);
return FALSE;
}
@@ -1595,8 +1593,9 @@ show_64bit_mfns:
nr_pages = xd->xc_core.header.xch_nr_pages;
for (b = 0; b < nr_pages; b += MAX_BATCH_SIZE) {
- if (read(xd->xfd, tmp64, sizeof(ulonglong) *
MAX_BATCH_SIZE) !=
- (MAX_BATCH_SIZE * sizeof(ulonglong))) {
+ size_t size = sizeof(ulonglong) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
+ if (read(xd->xfd, tmp64, size) != size) {
error(INFO, "cannot read index page %d\n", b);
return FALSE;
}
@@ -1709,13 +1708,11 @@ xc_core_elf_pfn_to_page_index(ulong pfn)
{
int i, b, start_index;
off_t offset;
- size_t size;
uint nr_pages;
ulong tmp;
struct xen_dumpcore_p2m p2m_batch[MAX_BATCH_SIZE];
offset = xd->xc_core.header.xch_index_offset;
- size = sizeof(struct xen_dumpcore_p2m) * MAX_BATCH_SIZE;
nr_pages = xd->xc_core.header.xch_nr_pages;
/*
@@ -1744,7 +1741,8 @@ xc_core_elf_pfn_to_page_index(ulong pfn)
error(FATAL, "cannot lseek to page index\n");
for (b = start_index; b < nr_pages; b += MAX_BATCH_SIZE) {
-
+ size_t size = sizeof(struct xen_dumpcore_p2m) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
if (read(xd->xfd, &p2m_batch[0], size) != size) {
error(INFO, "cannot read index page %d\n", b);
return PFN_NOT_FOUND;
@@ -1838,13 +1836,11 @@ xc_core_elf_pfn_valid(ulong pfn)
{
int i, b, start_index;
off_t offset;
- size_t size;
uint nr_pages;
ulong tmp;
uint64_t pfn_batch[MAX_BATCH_SIZE];
offset = xd->xc_core.header.xch_index_offset;
- size = sizeof(uint64_t) * MAX_BATCH_SIZE;
nr_pages = xd->xc_core.header.xch_nr_pages;
/*
@@ -1873,7 +1869,8 @@ xc_core_elf_pfn_valid(ulong pfn)
error(FATAL, "cannot lseek to page index\n");
for (b = start_index; b < nr_pages; b += MAX_BATCH_SIZE) {
-
+ size_t size = sizeof(uint64_t) *
+ MIN(MAX_BATCH_SIZE, nr_pages - b);
if (read(xd->xfd, &pfn_batch[0], size) != size) {
error(INFO, "cannot read index page %d\n", b);
return PFN_NOT_FOUND;
--
yamahata
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