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7017193: Small memory leak in get_stack_bounds os::create_stack_guard_pages

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Getline() returns -1 but still allocate memory for str

Reviewed-by: dcubed, coleenp
This commit is contained in:
Dmitry Samersoff 2011-03-30 19:38:07 +04:00
parent 66a08540c2
commit 52bf12aead
3 changed files with 70 additions and 34 deletions
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62
hotspot/src/os/linux/vm/os_linux.cpp
View file

@ -2648,45 +2648,39 @@ bool os::uncommit_memory(char* addr, size_t size) {
// writing thread stacks don't use growable mappings (i.e. those
// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
// only applies to the main thread.
static bool
get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
{
FILE *f = fopen("/proc/self/maps", "r");
if (f == NULL)
static
bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
char buf[128];
int fd, sz;
if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
return false;
while (!feof(f)) {
size_t dummy;
char *str = NULL;
ssize_t len = getline(&str, &dummy, f);
if (len == -1) {
fclose(f);
return false;
}
if (len > 0 && str[len-1] == '\n') {
str[len-1] = 0;
len--;
}
static const char *stack_str = "[stack]";
if (len > (ssize_t)strlen(stack_str)
&& (strcmp(str + len - strlen(stack_str), stack_str) == 0)) {
if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
uintptr_t sp = (uintptr_t)__builtin_frame_address(0);
if (sp >= *bottom && sp <= *top) {
free(str);
fclose(f);
return true;
}
}
}
free(str);
}
fclose(f);
const char kw[] = "[stack]";
const int kwlen = sizeof(kw)-1;
// Address part of /proc/self/maps couldn't be more than 128 bytes
while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
// Extract addresses
if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
if (sp >= *bottom && sp <= *top) {
::close(fd);
return true;
}
}
}
}
::close(fd);
return false;
}
// If the (growable) stack mapping already extends beyond the point
// where we're going to put our guard pages, truncate the mapping at
// that point by munmap()ping it. This ensures that when we later