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8312394: [linux] SIGSEGV if kernel was built without hugepage support #3172

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8312394: [linux] SIGSEGV if kernel was built without hugepage support #3172

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615223f
initial commit
tabata-d Mar 13, 2026
522c304
rerun GHA
tabata-d Mar 13, 2026
f3015fb
initial commit
tabata-d May 12, 2026
d78131a
Revert "initial commit"
tabata-d May 12, 2026
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36 changes: 20 additions & 16 deletions src/hotspot/os/linux/hugepages.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -111,20 +111,22 @@ static os::PageSizes scan_hugepages() {

os::PageSizes pagesizes;

DIR *dir = opendir(sys_hugepages);

struct dirent *entry;
size_t pagesize;
while ((entry = readdir(dir)) != NULL) {
if (entry->d_type == DT_DIR &&
sscanf(entry->d_name, "hugepages-%zukB", &pagesize) == 1) {
// The kernel is using kB, hotspot uses bytes
// Add each found Large Page Size to page_sizes
pagesize *= K;
pagesizes.add(pagesize);
DIR* dir = opendir(sys_hugepages);

if (dir != NULL) {
struct dirent *entry;
size_t pagesize;
while ((entry = readdir(dir)) != NULL) {
if (entry->d_type == DT_DIR &&
sscanf(entry->d_name, "hugepages-%zukB", &pagesize) == 1) {
// The kernel is using kB, hotspot uses bytes
// Add each found Large Page Size to page_sizes
pagesize *= K;
pagesizes.add(pagesize);
}
}
closedir(dir);
}
closedir(dir);

return pagesizes;
}
Expand All @@ -142,11 +144,13 @@ void StaticHugePageSupport::print_on(outputStream* os) {
}

void StaticHugePageSupport::scan_os() {
_pagesizes = scan_hugepages();
_default_hugepage_size = scan_default_hugepagesize();
assert(_pagesizes.contains(_default_hugepage_size),
"Unexpected configuration: default pagesize (" SIZE_FORMAT ") "
"has no associated directory in /sys/kernel/mm/hugepages..", _default_hugepage_size);
if (_default_hugepage_size > 0) {
_pagesizes = scan_hugepages();
assert(_pagesizes.contains(_default_hugepage_size),
"Unexpected configuration: default pagesize (" SIZE_FORMAT ") "
"has no associated directory in /sys/kernel/mm/hugepages..", _default_hugepage_size);
}
_initialized = true;
LogTarget(Info, pagesize) lt;
if (lt.is_enabled()) {
Expand Down