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Handle on-trace OOM errors from helper functions.

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This commit is contained in:
Mike Pall
2021-03-23 00:35:46 +01:00
parent ddd0fd8f37
commit a32aeadc68
24 changed files with 421 additions and 51 deletions
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247
src/lj_err.c
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@@ -52,6 +52,11 @@
** the wrapper function feature. Lua errors thrown through C++ frames
** cannot be caught by C++ code and C++ destructors are not run.
**
** - EXT can handle errors from internal helper functions that are called
** from JIT-compiled code (except for Windows/x86 and 32 bit ARM).
** INT has no choice but to call the panic handler, if this happens.
** Note: this is mainly relevant for out-of-memory errors.
**
** EXT is the default on all systems where the toolchain produces unwind
** tables by default (*). This is hard-coded and/or detected in src/Makefile.
** You can thwart the detection with: TARGET_XCFLAGS=-DLUAJIT_UNWIND_INTERNAL
@@ -305,12 +310,59 @@ LJ_FUNCA int lj_err_unwind_win(EXCEPTION_RECORD *rec,
return 1; /* ExceptionContinueSearch */
}
#if LJ_UNWIND_JIT
#if LJ_TARGET_X64
#define CONTEXT_REG_PC Rip
#elif LJ_TARGET_ARM64
#define CONTEXT_REG_PC Pc
#else
#error "NYI: Windows arch-specific unwinder for JIT-compiled code"
#endif
/* Windows unwinder for JIT-compiled code. */
static void err_unwind_win_jit(global_State *g, int errcode)
{
CONTEXT ctx;
UNWIND_HISTORY_TABLE hist;
memset(&hist, 0, sizeof(hist));
RtlCaptureContext(&ctx);
while (1) {
uintptr_t frame, base, addr = ctx.CONTEXT_REG_PC;
void *hdata;
PRUNTIME_FUNCTION func = RtlLookupFunctionEntry(addr, &base, &hist);
if (!func) { /* Found frame without .pdata: must be JIT-compiled code. */
ExitNo exitno;
uintptr_t stub = lj_trace_unwind(G2J(g), addr - sizeof(MCode), &exitno);
if (stub) { /* Jump to side exit to unwind the trace. */
ctx.CONTEXT_REG_PC = stub;
G2J(g)->exitcode = errcode;
RtlRestoreContext(&ctx, NULL); /* Does not return. */
}
break;
}
RtlVirtualUnwind(UNW_FLAG_NHANDLER, base, addr, func,
&ctx, &hdata, &frame, NULL);
if (!addr) break;
}
/* Unwinding failed, if we end up here. */
}
#endif
/* Raise Windows exception. */
static void err_raise_ext(global_State *g, int errcode)
{
#if LJ_HASJIT
#if LJ_UNWIND_JIT
if (tvref(g->jit_base)) {
err_unwind_win_jit(g, errcode);
return; /* Unwinding failed. */
}
#elif LJ_HASJIT
/* Cannot catch on-trace errors for Windows/x86 SEH. Unwind to interpreter. */
setmref(g->jit_base, NULL);
#endif
UNUSED(g);
RaiseException(LJ_EXCODE_MAKE(errcode), 1 /* EH_NONCONTINUABLE */, 0, NULL);
}
@@ -324,6 +376,7 @@ static void err_raise_ext(global_State *g, int errcode)
typedef struct _Unwind_Context _Unwind_Context;
#define _URC_OK 0
#define _URC_FATAL_PHASE2_ERROR 2
#define _URC_FATAL_PHASE1_ERROR 3
#define _URC_HANDLER_FOUND 6
#define _URC_INSTALL_CONTEXT 7
@@ -343,9 +396,11 @@ typedef struct _Unwind_Exception
void (*excleanup)(int, struct _Unwind_Exception *);
uintptr_t p1, p2;
} __attribute__((__aligned__)) _Unwind_Exception;
#define UNWIND_EXCEPTION_TYPE _Unwind_Exception
extern uintptr_t _Unwind_GetCFA(_Unwind_Context *);
extern void _Unwind_SetGR(_Unwind_Context *, int, uintptr_t);
extern uintptr_t _Unwind_GetIP(_Unwind_Context *);
extern void _Unwind_SetIP(_Unwind_Context *, uintptr_t);
extern void _Unwind_DeleteException(_Unwind_Exception *);
extern int _Unwind_RaiseException(_Unwind_Exception *);
@@ -418,8 +473,130 @@ LJ_FUNCA int lj_err_unwind_dwarf(int version, int actions,
return _URC_CONTINUE_UNWIND;
}
#if LJ_UNWIND_EXT
static __thread _Unwind_Exception static_uex;
#if LJ_UNWIND_EXT && defined(LUA_USE_ASSERT)
struct dwarf_eh_bases { void *tbase, *dbase, *func; };
extern const void *_Unwind_Find_FDE(void *pc, struct dwarf_eh_bases *bases);
/* Verify that external error handling actually has a chance to work. */
void lj_err_verify(void)
{
struct dwarf_eh_bases ehb;
lj_assertX(_Unwind_Find_FDE((void *)lj_err_throw, &ehb), "broken build: external frame unwinding enabled, but missing -funwind-tables");
lj_assertX(_Unwind_Find_FDE((void *)_Unwind_RaiseException, &ehb), "broken build: external frame unwinding enabled, but system libraries have no unwind tables");
}
#endif
#if LJ_UNWIND_JIT
/* DWARF2 personality handler for JIT-compiled code. */
static int err_unwind_jit(int version, int actions,
uint64_t uexclass, _Unwind_Exception *uex, _Unwind_Context *ctx)
{
/* NYI: FFI C++ exception interoperability. */
if (version != 1 || !LJ_UEXCLASS_CHECK(uexclass))
return _URC_FATAL_PHASE1_ERROR;
if ((actions & _UA_SEARCH_PHASE)) {
return _URC_HANDLER_FOUND;
}
if ((actions & _UA_CLEANUP_PHASE)) {
global_State *g = *(global_State **)(uex+1);
ExitNo exitno;
uintptr_t addr = _Unwind_GetIP(ctx); /* Return address _after_ call. */
uintptr_t stub = lj_trace_unwind(G2J(g), addr - sizeof(MCode), &exitno);
lj_assertG(tvref(g->jit_base), "unexpected throw across mcode frame");
if (stub) { /* Jump to side exit to unwind the trace. */
G2J(g)->exitcode = LJ_UEXCLASS_ERRCODE(uexclass);
#ifdef LJ_TARGET_MIPS
_Unwind_SetGR(ctx, 4, stub);
_Unwind_SetGR(ctx, 5, exitno);
_Unwind_SetIP(ctx, (uintptr_t)(void *)lj_vm_unwind_stub);
#else
_Unwind_SetIP(ctx, stub);
#endif
return _URC_INSTALL_CONTEXT;
}
return _URC_FATAL_PHASE2_ERROR;
}
return _URC_FATAL_PHASE1_ERROR;
}
/* DWARF2 template frame info for JIT-compiled code.
**
** After copying the template to the start of the mcode segment,
** the frame handler function and the code size is patched.
** The frame handler always installs a new context to jump to the exit,
** so don't bother to add any unwind opcodes.
*/
static const uint8_t err_frame_jit_template[] = {
#if LJ_BE
0,0,0,
#endif
LJ_64 ? 0x1c : 0x14, /* CIE length. */
#if LJ_LE
0,0,0,
#endif
0,0,0,0, 1, 'z','P','R',0, /* CIE mark, CIE version, augmentation. */
1, LJ_64 ? 0x78 : 0x7c, LJ_TARGET_EHRAREG, /* Code/data align, RA. */
#if LJ_64
10, 0, 0,0,0,0,0,0,0,0, 0x1b, /* Aug. data ABS handler, PCREL|SDATA4 code. */
0,0,0,0,0, /* Alignment. */
#else
6, 0, 0,0,0,0, 0x1b, /* Aug. data ABS handler, PCREL|SDATA4 code. */
0, /* Alignment. */
#endif
#if LJ_BE
0,0,0,
#endif
LJ_64 ? 0x14 : 0x10, /* FDE length. */
0,0,0,
LJ_64 ? 0x24 : 0x1c, /* CIE offset. */
0,0,0,
LJ_64 ? 0x14 : 0x10, /* Code offset. After Final FDE. */
#if LJ_LE
0,0,0,
#endif
0,0,0,0, 0, 0,0,0, /* Code size, augmentation length, alignment. */
#if LJ_64
0,0,0,0, /* Alignment. */
#endif
0,0,0,0 /* Final FDE. */
};
#define ERR_FRAME_JIT_OFS_HANDLER 0x12
#define ERR_FRAME_JIT_OFS_FDE (LJ_64 ? 0x20 : 0x18)
#define ERR_FRAME_JIT_OFS_CODE_SIZE (LJ_64 ? 0x2c : 0x24)
#if LJ_TARGET_OSX
#define ERR_FRAME_JIT_OFS_REGISTER ERR_FRAME_JIT_OFS_FDE
#else
#define ERR_FRAME_JIT_OFS_REGISTER 0
#endif
extern void __register_frame(const void *);
extern void __deregister_frame(const void *);
uint8_t *lj_err_register_mcode(void *base, size_t sz, uint8_t *info)
{
void **handler;
memcpy(info, err_frame_jit_template, sizeof(err_frame_jit_template));
handler = (void *)err_unwind_jit;
memcpy(info + ERR_FRAME_JIT_OFS_HANDLER, &handler, sizeof(handler));
*(uint32_t *)(info + ERR_FRAME_JIT_OFS_CODE_SIZE) =
(uint32_t)(sz - sizeof(err_frame_jit_template) - (info - (uint8_t *)base));
__register_frame(info + ERR_FRAME_JIT_OFS_REGISTER);
#ifdef LUA_USE_ASSERT
{
struct dwarf_eh_bases ehb;
lj_assertX(_Unwind_Find_FDE(info + sizeof(err_frame_jit_template)+1, &ehb),
"bad JIT unwind table registration");
}
#endif
return info + sizeof(err_frame_jit_template);
}
void lj_err_deregister_mcode(void *base, size_t sz, uint8_t *info)
{
UNUSED(base); UNUSED(sz);
__deregister_frame(info + ERR_FRAME_JIT_OFS_REGISTER);
}
#endif
#else /* LJ_TARGET_ARM */
@@ -430,6 +607,7 @@ static __thread _Unwind_Exception static_uex;
#define _US_FORCE_UNWIND 8
typedef struct _Unwind_Control_Block _Unwind_Control_Block;
#define UNWIND_EXCEPTION_TYPE _Unwind_Control_Block
struct _Unwind_Control_Block {
uint64_t exclass;
@@ -488,25 +666,62 @@ LJ_FUNCA int lj_err_unwind_arm(int state, _Unwind_Control_Block *ucb,
}
if (__gnu_unwind_frame(ucb, ctx) != _URC_OK)
return _URC_FAILURE;
#ifdef LUA_USE_ASSERT
/* We should never get here unless this is a forced unwind aka backtrace. */
if (_Unwind_GetGR(ctx, 0) == 0xff33aa77) {
_Unwind_SetGR(ctx, 0, 0xff33aa88);
}
#endif
return _URC_CONTINUE_UNWIND;
}
#if LJ_UNWIND_EXT
static __thread _Unwind_Control_Block static_uex;
#if LJ_UNWIND_EXT && defined(LUA_USE_ASSERT)
typedef int (*_Unwind_Trace_Fn)(_Unwind_Context *, void *);
extern int _Unwind_Backtrace(_Unwind_Trace_Fn, void *);
static int err_verify_bt(_Unwind_Context *ctx, int *got)
{
if (_Unwind_GetGR(ctx, 0) == 0xff33aa88) { *got = 2; }
else if (*got == 0) { *got = 1; _Unwind_SetGR(ctx, 0, 0xff33aa77); }
return _URC_OK;
}
/* Verify that external error handling actually has a chance to work. */
void lj_err_verify(void)
{
int got = 0;
_Unwind_Backtrace((_Unwind_Trace_Fn)err_verify_bt, &got);
lj_assertX(got == 2, "broken build: external frame unwinding enabled, but missing -funwind-tables");
}
#endif
/*
** Note: LJ_UNWIND_JIT is not implemented for 32 bit ARM.
**
** The quirky ARM unwind API doesn't have __register_frame().
** A potential workaround might involve _Unwind_Backtrace.
** But most 32 bit ARM targets don't qualify for LJ_UNWIND_EXT, anyway,
** since they are built without unwind tables by default.
*/
#endif /* LJ_TARGET_ARM */
#if LJ_UNWIND_EXT
static __thread struct {
UNWIND_EXCEPTION_TYPE ex;
global_State *g;
} static_uex;
/* Raise external exception. */
static void err_raise_ext(global_State *g, int errcode)
{
#if LJ_HASJIT
setmref(g->jit_base, NULL);
#endif
memset(&static_uex, 0, sizeof(static_uex));
static_uex.exclass = LJ_UEXCLASS_MAKE(errcode);
_Unwind_RaiseException(&static_uex);
static_uex.ex.exclass = LJ_UEXCLASS_MAKE(errcode);
static_uex.g = g;
_Unwind_RaiseException(&static_uex.ex);
}
#endif
#endif
@@ -615,7 +830,7 @@ static ptrdiff_t finderrfunc(lua_State *L)
/* Runtime error. */
LJ_NOINLINE void LJ_FASTCALL lj_err_run(lua_State *L)
{
ptrdiff_t ef = finderrfunc(L);
ptrdiff_t ef = (LJ_HASJIT && tvref(G(L)->jit_base)) ? 0 : finderrfunc(L);
if (ef) {
TValue *errfunc = restorestack(L, ef);
TValue *top = L->top;
@@ -634,6 +849,16 @@ LJ_NOINLINE void LJ_FASTCALL lj_err_run(lua_State *L)
lj_err_throw(L, LUA_ERRRUN);
}
#if LJ_HASJIT
LJ_NOINLINE void LJ_FASTCALL lj_err_trace(lua_State *L, int errcode)
{
if (errcode == LUA_ERRRUN)
lj_err_run(L);
else
lj_err_throw(L, errcode);
}
#endif
/* Formatted runtime error message. */
LJ_NORET LJ_NOINLINE static void err_msgv(lua_State *L, ErrMsg em, ...)
{