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Fix GH-21368 crash: runtime orig_handler lookup in escape_if_undef #21710

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Fix GH-21368 crash: runtime orig_handler lookup in escape_if_undef #21710

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4 changes: 2 additions & 2 deletions ext/opcache/jit/zend_jit_ir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8068,7 +8068,7 @@ static int zend_jit_defined(zend_jit_ctx *jit, const zend_op *opline, uint8_t sm
return 1;
}

static int zend_jit_escape_if_undef(zend_jit_ctx *jit, int var, uint32_t flags, const zend_op *opline, const zend_op_array *op_array, int8_t reg)
static int zend_jit_escape_if_undef(zend_jit_ctx *jit, int var, uint32_t flags, const zend_op *opline, int8_t reg)
{
zend_jit_addr reg_addr = ZEND_ADDR_REF_ZVAL(zend_jit_deopt_rload(jit, IR_ADDR, reg));
ir_ref if_def = ir_IF(jit_Z_TYPE(jit, reg_addr));
Expand All @@ -8094,7 +8094,7 @@ static int zend_jit_escape_if_undef(zend_jit_ctx *jit, int var, uint32_t flags,

/* We can't use trace_escape() because opcode handler may be overridden by JIT */
zend_jit_op_array_trace_extension *jit_extension =
(zend_jit_op_array_trace_extension*)ZEND_FUNC_INFO(op_array);
(zend_jit_op_array_trace_extension*)ZEND_FUNC_INFO(jit->current_op_array);
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@dstogov dstogov Apr 20, 2026

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Are you sure jit->current_op_array is always initialized?
It seems, it may be NULL on the following patch - zend_jit_trace_exit() -> zend_jit_trace_hot_side() -> zend_jit_blacklist_trace_exit() -> zend_jit_trace_exit_to_vm() - > zend_jit_trace_deoptimization() -> zend_jit_escape_if_undef().

May be I'm wrong...

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@iliaal iliaal Apr 20, 2026

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exit_info.op_array is written in one place, zend_jit_trace_get_exit_point (trace.c:197), and the surrounding code at trace.c:146-164 assigns op_array and stack_size together: JIT_G(current_frame) non-NULL gives a real op_array with some stack_size; the else branch sets both op_array = NULL and stack_size = 0 in the same step.

So on your path, ctx.current_op_array == NULL only when exit_info.stack_size == 0, which means zend_jit_trace_deoptimization loops over zero entries, check2 stays at -1, and zend_jit_escape_if_undef at trace.c:3606 isn't called. The NULL never reaches ZEND_FUNC_INFO(jit->current_op_array).

Can add ZEND_ASSERT(exit_info[exit_num].op_array || exit_info[exit_num].stack_size == 0) to make it explicit.

size_t offset = jit_extension->offset;
ir_ref ref = ir_CONST_ADDR(ZEND_OP_TRACE_INFO((opline - 1), offset)->orig_handler);
if (GCC_GLOBAL_REGS) {
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4 changes: 3 additions & 1 deletion ext/opcache/jit/zend_jit_trace.c
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Expand Up @@ -3603,7 +3603,7 @@ static int zend_jit_trace_deoptimization(

ZEND_ASSERT(STACK_FLAGS(parent_stack, check2) == ZREG_ZVAL_COPY);
ZEND_ASSERT(reg != ZREG_NONE);
if (!zend_jit_escape_if_undef(jit, check2, flags, opline, exit_info->op_array, reg)) {
if (!zend_jit_escape_if_undef(jit, check2, flags, opline, reg)) {
return 0;
}
if (!zend_jit_restore_zval(jit, EX_NUM_TO_VAR(check2), reg)) {
Expand Down Expand Up @@ -7374,6 +7374,8 @@ static const void *zend_jit_trace_exit_to_vm(uint32_t trace_num, uint32_t exit_n
zend_jit_traces[trace_num].stack_map + zend_jit_traces[trace_num].exit_info[exit_num].stack_offset :
NULL;

ctx.current_op_array = zend_jit_traces[trace_num].exit_info[exit_num].op_array;

if (!zend_jit_trace_deoptimization(&ctx,
&zend_jit_traces[trace_num].exit_info[exit_num],
stack, stack_size, NULL, NULL,
Expand Down
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