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LoongT4oLoongT4o
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Fix the JIT buffer relocation failure at the corner case
Avoid missing possible candidates due to the large address range of the free segment. Eg,  48000000-49400000 r-xs 08000000 00:0f 39322841               segment1 7ffff2ec8000-7ffff2f49000 rw-p 00000000 00:00 0              segment2 7ffff6fae000-7ffff735c000 r-xp 00200000 08:02 11538515       /usr/local/sbin/php-fpm original code will miss the opportunity between [7ffff2ec** - 7ffff2ec8000]. Fix issue #11265. Signed-off-by: Long, Tao <tao.long@intel.com> Signed-off-by: Wang, Xue <xue1.wang@intel.com>
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‎ext/opcache/shared_alloc_mmap.c‎

Lines changed: 97 additions & 89 deletions
Original file line numberDiff line numberDiff line change
@@ -52,102 +52,110 @@
5252
static void *find_prefered_mmap_base(size_t requested_size)
5353
{
5454
size_t huge_page_size = 2 * 1024 * 1024;
55-
uintptr_t last_free_addr = 0;
56-
uintptr_t last_candidate = (uintptr_t)MAP_FAILED;
57-
uintptr_t start, end, text_start = 0;
55+
uintptr_t last_free_addr = 0;
56+
uintptr_t last_candidate = (uintptr_t)MAP_FAILED;
57+
uintptr_t start, end, text_start = 0;
5858
#if defined(__linux__)
59-
FILE *f;
60-
char buffer[MAXPATHLEN];
59+
FILE *f;
60+
char buffer[MAXPATHLEN];
6161

62-
f = fopen("/proc/self/maps", "r");
63-
if (!f) {
64-
return MAP_FAILED;
65-
}
62+
f = fopen("/proc/self/maps", "r");
63+
if (!f) {
64+
return MAP_FAILED;
65+
}
6666

67-
while (fgets(buffer, MAXPATHLEN, f) && sscanf(buffer, "%lx-%lx", &start, &end) == 2) {
68-
if ((uintptr_t)execute_ex >= start) {
69-
/* the current segment lays before PHP .text segment or PHP .text segment itself */
70-
if (last_free_addr + requested_size <= start) {
71-
last_candidate = last_free_addr;
72-
}
73-
if ((uintptr_t)execute_ex < end) {
74-
/* the current segment is PHP .text segment itself */
75-
if (last_candidate != (uintptr_t)MAP_FAILED) {
76-
if (end - last_candidate < UINT32_MAX) {
77-
/* we have found a big enough hole before the text segment */
78-
break;
79-
}
80-
last_candidate = (uintptr_t)MAP_FAILED;
67+
while (fgets(buffer, MAXPATHLEN, f) && sscanf(buffer, "%lx-%lx", &start, &end) == 2) {
68+
if ((uintptr_t)execute_ex >= start) {
69+
/* the current segment lays before PHP .text segment or PHP .text segment itself */
70+
/*Search for candidates at the end of the free segment near the .text segment
71+
to prevent candidates from being missed due to large hole*/
72+
if (last_free_addr + requested_size <= start) {
73+
last_candidate = ZEND_MM_ALIGNED_SIZE_EX(start - requested_size, huge_page_size);
74+
if (last_candidate + requested_size > start) {
75+
last_candidate -= huge_page_size;
8176
}
82-
text_start = start;
83-
}
84-
} else {
85-
/* the current segment lays after PHP .text segment */
86-
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
87-
/* the current segment and the following segments lay too far from PHP .text segment */
88-
break;
89-
}
90-
if (last_free_addr + requested_size <= start) {
91-
last_candidate = last_free_addr;
92-
break;
93-
}
94-
}
95-
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(end, huge_page_size);
77+
}
78+
if ((uintptr_t)execute_ex < end) {
79+
/* the current segment is PHP .text segment itself */
80+
if (last_candidate != (uintptr_t)MAP_FAILED) {
81+
if (end - last_candidate < UINT32_MAX) {
82+
/* we have found a big enough hole before the .text segment */
83+
break;
84+
}
85+
last_candidate = (uintptr_t)MAP_FAILED;
86+
}
87+
text_start = start;
88+
}
89+
} else {
90+
/* the current segment lays after PHP .text segment */
91+
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
92+
/* the current segment and the following segments lay too far from PHP .text segment */
93+
break;
94+
}
95+
if (last_free_addr + requested_size <= start) {
96+
last_candidate = last_free_addr;
97+
break;
98+
}
99+
}
100+
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(end, huge_page_size);
96101

97-
}
98-
fclose(f);
102+
}
103+
fclose(f);
99104
#elif defined(__FreeBSD__)
100-
size_t s = 0;
101-
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_VMMAP, getpid()};
102-
if (sysctl(mib, 4, NULL, &s, NULL, 0) == 0) {
103-
s = s * 4 / 3;
104-
void *addr = mmap(NULL, s, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
105-
if (addr != MAP_FAILED) {
106-
if (sysctl(mib, 4, addr, &s, NULL, 0) == 0) {
107-
start = (uintptr_t)addr;
108-
end = start + s;
109-
while (start < end) {
110-
struct kinfo_vmentry *entry = (struct kinfo_vmentry *)start;
111-
size_t sz = entry->kve_structsize;
112-
if (sz == 0) {
113-
break;
114-
}
115-
uintptr_t e_start = entry->kve_start;
116-
uintptr_t e_end = entry->kve_end;
117-
if ((uintptr_t)execute_ex >= e_start) {
118-
/* the current segment lays before PHP .text segment or PHP .text segment itself */
119-
if (last_free_addr + requested_size <= e_start) {
120-
last_candidate = last_free_addr;
121-
}
122-
if ((uintptr_t)execute_ex < e_end) {
123-
/* the current segment is PHP .text segment itself */
124-
if (last_candidate != (uintptr_t)MAP_FAILED) {
125-
if (e_end - last_candidate < UINT32_MAX) {
126-
/* we have found a big enough hole before the text segment */
127-
break;
128-
}
129-
last_candidate = (uintptr_t)MAP_FAILED;
105+
size_t s = 0;
106+
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_VMMAP, getpid()};
107+
if (sysctl(mib, 4, NULL, &s, NULL, 0) == 0) {
108+
s = s * 4 / 3;
109+
void *addr = mmap(NULL, s, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
110+
if (addr != MAP_FAILED) {
111+
if (sysctl(mib, 4, addr, &s, NULL, 0) == 0) {
112+
start = (uintptr_t)addr;
113+
end = start + s;
114+
while (start < end) {
115+
struct kinfo_vmentry *entry = (struct kinfo_vmentry *)start;
116+
size_t sz = entry->kve_structsize;
117+
if (sz == 0) {
118+
break;
119+
}
120+
uintptr_t e_start = entry->kve_start;
121+
uintptr_t e_end = entry->kve_end;
122+
if ((uintptr_t)execute_ex >= e_start) {
123+
/* the current segment lays before PHP .text segment or PHP .text segment itself */
124+
if (last_free_addr + requested_size <= e_start) {
125+
last_candidate = ZEND_MM_ALIGNED_SIZE_EX(e_start - requested_size, huge_page_size);
126+
if (last_candidate + requested_size > e_start) {
127+
last_candidate -= huge_page_size;
130128
}
131-
text_start = e_start;
132-
}
133-
} else {
134-
/* the current segment lays after PHP .text segment */
135-
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
136-
/* the current segment and the following segments lay too far from PHP .text segment */
137-
break;
138-
}
139-
if (last_free_addr + requested_size <= e_start) {
140-
last_candidate = last_free_addr;
141-
break;
142-
}
143-
}
144-
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(e_end, huge_page_size);
145-
start += sz;
146-
}
147-
}
148-
munmap(addr, s);
149-
}
150-
}
129+
}
130+
if ((uintptr_t)execute_ex < e_end) {
131+
/* the current segment is PHP .text segment itself */
132+
if (last_candidate != (uintptr_t)MAP_FAILED) {
133+
if (e_end - last_candidate < UINT32_MAX) {
134+
/* we have found a big enough hole before the text segment */
135+
break;
136+
}
137+
last_candidate = (uintptr_t)MAP_FAILED;
138+
}
139+
text_start = e_start;
140+
}
141+
} else {
142+
/* the current segment lays after PHP .text segment */
143+
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
144+
/* the current segment and the following segments lay too far from PHP .text segment */
145+
break;
146+
}
147+
if (last_free_addr + requested_size <= e_start) {
148+
last_candidate = last_free_addr;
149+
break;
150+
}
151+
}
152+
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(e_end, huge_page_size);
153+
start += sz;
154+
}
155+
}
156+
munmap(addr, s);
157+
}
158+
}
151159
#endif
152160

153161
return (void*)last_candidate;

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