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Fix race condition in zend_runtime_jit(), zend_jit_hot_func()

zend_runtime_jit() prevents concurrent compilation with
zend_shared_alloc_lock(), but this doesn't prevent blocked threads from
trying to compile the function again after they acquire the lock.

In the case of GH-19889, one of the function entries is compiled with
zend_jit_handler(), which fails when the op handler has already been replaced by
a JIT'ed handler.

Fix by marking compiled functions with a new flag ZEND_FUNC_JITED, and
skipping compilation of marked functions. The same fix is applied to
zend_jit_hot_func().

Fixes GH-19889
Closes GH-19971
This commit is contained in:
Arnaud Le Blanc
2025-09-26 10:24:45 +02:00
parent 08924cd8c4
commit 359ad80c4a
3 changed files with 11 additions and 5 deletions

2
NEWS
View File

@@ -44,6 +44,8 @@ PHP NEWS
. Fixed bug GH-19669 (assertion failure in zend_jit_trace_type_to_info_ex).
(Arnaud)
. Fixed bug GH-19831 (function JIT may not deref property value). (Arnaud)
. Fixed bug GH-19889 (race condition in zend_runtime_jit(),
zend_jit_hot_func()). (Arnaud)
- Phar:
. Fix memory leak and invalid continuation after tar header writing fails.

View File

@@ -39,7 +39,7 @@
#define ZEND_FUNC_JIT_ON_PROF_REQUEST (1<<14) /* used by JIT */
#define ZEND_FUNC_JIT_ON_HOT_COUNTERS (1<<15) /* used by JIT */
#define ZEND_FUNC_JIT_ON_HOT_TRACE (1<<16) /* used by JIT */
#define ZEND_FUNC_JITED (1<<17) /* used by JIT */
typedef struct _zend_func_info zend_func_info;
typedef struct _zend_call_info zend_call_info;

View File

@@ -2945,8 +2945,9 @@ static int ZEND_FASTCALL zend_runtime_jit(void)
bool do_bailout = 0;
zend_shared_alloc_lock();
jit_extension = (zend_jit_op_array_extension*)ZEND_FUNC_INFO(op_array);
if (ZEND_FUNC_INFO(op_array)) {
if (jit_extension && !(jit_extension->func_info.flags & ZEND_FUNC_JITED)) {
SHM_UNPROTECT();
zend_jit_unprotect();
@@ -2958,11 +2959,12 @@ static int ZEND_FASTCALL zend_runtime_jit(void)
opline++;
}
}
jit_extension = (zend_jit_op_array_extension*)ZEND_FUNC_INFO(op_array);
opline->handler = jit_extension->orig_handler;
((zend_op*)opline)->handler = jit_extension->orig_handler;
/* perform real JIT for this function */
zend_real_jit_func(op_array, NULL, NULL, ZEND_JIT_ON_FIRST_EXEC);
jit_extension->func_info.flags |= ZEND_FUNC_JITED;
} zend_catch {
do_bailout = true;
} zend_end_try();
@@ -3024,7 +3026,7 @@ void ZEND_FASTCALL zend_jit_hot_func(zend_execute_data *execute_data, const zend
zend_shared_alloc_lock();
jit_extension = (zend_jit_op_array_hot_extension*)ZEND_FUNC_INFO(op_array);
if (jit_extension) {
if (jit_extension && !(jit_extension->func_info.flags & ZEND_FUNC_JITED)) {
SHM_UNPROTECT();
zend_jit_unprotect();
@@ -3039,6 +3041,8 @@ void ZEND_FASTCALL zend_jit_hot_func(zend_execute_data *execute_data, const zend
/* perform real JIT for this function */
zend_real_jit_func(op_array, NULL, opline, ZEND_JIT_ON_HOT_COUNTERS);
jit_extension->func_info.flags |= ZEND_FUNC_JITED;
} zend_catch {
do_bailout = 1;
} zend_end_try();