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Fix JIT fuzzers never enabling the JIT #24717

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Merged
ndossche merged 1 commit into from
Oct 26, 2026
+17 −8
Merged

Fix JIT fuzzers never enabling the JIT #24717

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9 changes: 9 additions & 0 deletions sapi/fuzzer/fuzzer-execute-common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -146,3 +146,12 @@ ZEND_ATTRIBUTE_UNUSED static void opcache_invalidate(void) {
zval_ptr_dtor(&retval);
EG(exception) = exception;
}

ZEND_ATTRIBUTE_UNUSED static void set_jit_option(zend_string *jit_option, const char *value) {
if (zend_alter_ini_entry_chars(
jit_option, value, strlen(value), PHP_INI_USER, PHP_INI_STAGE_RUNTIME) == FAILURE) {
/* Fail loudly instead of silently fuzzing without the JIT. */
fprintf(stderr, "Failed to set opcache.jit=%s\n", value);
abort();
}
}
8 changes: 4 additions & 4 deletions sapi/fuzzer/fuzzer-function-jit.c
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Expand Up @@ -27,15 +27,13 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
* we bail out here, as the JIT code may loop infinitely. */
steps_left = MAX_STEPS;
bailed_out = false;
zend_alter_ini_entry_chars(
jit_option, "off", sizeof("off")-1, PHP_INI_USER, PHP_INI_STAGE_RUNTIME);
set_jit_option(jit_option, "off");
fuzzer_do_request_from_buffer(
FILE_NAME, (const char *) Data, Size, /* execute */ 1, opcache_invalidate);

if (!bailed_out) {
steps_left = MAX_STEPS;
zend_alter_ini_entry_chars(jit_option,
"function", sizeof("function")-1, PHP_INI_USER, PHP_INI_STAGE_RUNTIME);
set_jit_option(jit_option, "function");
zend_execute_ex = orig_execute_ex;
fuzzer_do_request_from_buffer(
FILE_NAME, (const char *) Data, Size, /* execute */ 1, opcache_invalidate);
Expand All @@ -50,6 +48,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
int LLVMFuzzerInitialize(int *argc, char ***argv) {
char ini_buf[512];
snprintf(ini_buf, sizeof(ini_buf),
/* The default opcache.jit=disable does not allow enabling the JIT at runtime. */
"opcache.jit=off\n"
"opcache.validate_timestamps=0\n"
"opcache.file_update_protection=0\n"
"opcache.jit_buffer_size=128M\n"
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8 changes: 4 additions & 4 deletions sapi/fuzzer/fuzzer-tracing-jit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,15 +27,13 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
* we bail out here, as the JIT code may loop infinitely. */
steps_left = MAX_STEPS;
bailed_out = false;
zend_alter_ini_entry_chars(
jit_option, "off", sizeof("off")-1, PHP_INI_USER, PHP_INI_STAGE_RUNTIME);
set_jit_option(jit_option, "off");
fuzzer_do_request_from_buffer(
FILE_NAME, (const char *) Data, Size, /* execute */ 1, opcache_invalidate);

if (!bailed_out) {
steps_left = MAX_STEPS;
zend_alter_ini_entry_chars(jit_option,
"tracing", sizeof("tracing")-1, PHP_INI_USER, PHP_INI_STAGE_RUNTIME);
set_jit_option(jit_option, "tracing");
zend_execute_ex = orig_execute_ex;
/* Trace & compile */
fuzzer_do_request_from_buffer(
Expand All @@ -54,6 +52,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
int LLVMFuzzerInitialize(int *argc, char ***argv) {
char ini_buf[512];
snprintf(ini_buf, sizeof(ini_buf),
/* The default opcache.jit=disable does not allow enabling the JIT at runtime. */
"opcache.jit=off\n"
"opcache.validate_timestamps=0\n"
"opcache.file_update_protection=0\n"
"opcache.memory_consumption=1024\n"
Expand Down
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