From: Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Maxim Kokryashkin <m.kokryashkin@tarantool.org>, Sergey Bronnikov <sergeyb@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: [Tarantool-patches] [PATCH luajit] FFI: Drop finalizer table rehash after GC cycle. Date: Mon, 2 Sep 2024 15:54:21 +0300 [thread overview] Message-ID: <20240902125421.16727-1-skaplun@tarantool.org> (raw) From: Mike Pall <mike> Reported by Sergey Kaplun. (cherry picked from commit fb22d0f80f291827a4004e16bc589b54bcc4a3c7) The raising of the OOM error when rehashing the finalizer table (when we can't allocate a new hash part) leads to crashes in either `lj_trace_exit()` or `lj_trace_unwind()` due to unprotected error raising, which either has no DWARF eh_frame or loses the context of the JIT compiler. This patch drops rehashing of the finalizer table to avoid these crashes. Sergey Kaplun: * added the description and the test for the problem Part of tarantool/tarantool#10199 Resolves tarantool/tarantool#10290 --- Branch: https://github.com/tarantool/luajit/tree/skaplun/lj-1247-fin-tab-rehashing-on-trace Related Issues: * https://github.com/tarantool/tarantool/issues/10290 * https://github.com/LuaJIT/LuaJIT/issues/1247 * https://github.com/tarantool/tarantool/issues/10199 src/lj_gc.c | 7 - src/lj_obj.h | 2 +- test/tarantool-tests/CMakeLists.txt | 1 + ...j-1247-fin-tab-rehashing-on-trace.test.lua | 127 ++++++++++++++++++ .../CMakeLists.txt | 1 + .../lj_1247_allocinject.c | 49 +++++++ 6 files changed, 179 insertions(+), 8 deletions(-) create mode 100644 test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace.test.lua create mode 100644 test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/CMakeLists.txt create mode 100644 test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/lj_1247_allocinject.c diff --git a/src/lj_gc.c b/src/lj_gc.c index 4c222f21..a2fc93a0 100644 --- a/src/lj_gc.c +++ b/src/lj_gc.c @@ -548,7 +548,6 @@ static void gc_finalize(lua_State *L) setcdataV(L, &tmp, gco2cd(o)); tv = lj_tab_set(L, tabref(g->gcroot[GCROOT_FFI_FIN]), &tmp); if (!tvisnil(tv)) { - g->gc.nocdatafin = 0; copyTV(L, &tmp, tv); setnilV(tv); /* Clear entry in finalizer table. */ gc_call_finalizer(g, L, &tmp, o); @@ -694,9 +693,6 @@ static size_t gc_onestep(lua_State *L) lj_str_resize(L, g->strmask >> 1); /* Shrink string table. */ if (gcref(g->gc.mmudata)) { /* Need any finalizations? */ g->gc.state = GCSfinalize; -#if LJ_HASFFI - g->gc.nocdatafin = 1; -#endif } else { /* Otherwise skip this phase to help the JIT. */ g->gc.state = GCSpause; /* End of GC cycle. */ g->gc.debt = 0; @@ -713,9 +709,6 @@ static size_t gc_onestep(lua_State *L) g->gc.estimate -= GCFINALIZECOST; return GCFINALIZECOST; } -#if LJ_HASFFI - if (!g->gc.nocdatafin) lj_tab_rehash(L, tabref(g->gcroot[GCROOT_FFI_FIN])); -#endif g->gc.state = GCSpause; /* End of GC cycle. */ g->gc.debt = 0; return 0; diff --git a/src/lj_obj.h b/src/lj_obj.h index 06ea0cd0..ff22e5f8 100644 --- a/src/lj_obj.h +++ b/src/lj_obj.h @@ -611,7 +611,7 @@ typedef struct GCState { GCSize threshold; /* Memory threshold. */ uint8_t currentwhite; /* Current white color. */ uint8_t state; /* GC state. */ - uint8_t nocdatafin; /* No cdata finalizer called. */ + uint8_t unused0; #if LJ_64 uint8_t lightudnum; /* Number of lightuserdata segments - 1. */ #else diff --git a/test/tarantool-tests/CMakeLists.txt b/test/tarantool-tests/CMakeLists.txt index e3750bf3..e5d5a470 100644 --- a/test/tarantool-tests/CMakeLists.txt +++ b/test/tarantool-tests/CMakeLists.txt @@ -37,6 +37,7 @@ add_subdirectory(lj-flush-on-trace) add_subdirectory(lj-1004-oom-error-frame) add_subdirectory(lj-1066-fix-cur_L-after-coroutine-resume) add_subdirectory(lj-1166-error-stitch) +add_subdirectory(lj-1247-fin-tab-rehashing-on-trace) # The part of the memory profiler toolchain is located in tools # directory, jit, profiler, and bytecode toolchains are located diff --git a/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace.test.lua b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace.test.lua new file mode 100644 index 00000000..308043a2 --- /dev/null +++ b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace.test.lua @@ -0,0 +1,127 @@ +local tap = require('tap') + +-- The test file to demonstrate the incorrect JIT behaviour during +-- OOM on the finalizer table rehashing in the context of the JIT +-- trace. +-- See also: +-- * https://github.com/LuaJIT/LuaJIT/issues/1247, +-- * https://github.com/tarantool/tarantool/issues/10290. + +local test = tap.test('lj-1247-fin-tab-rehashing-on-trace'):skipcond({ + ['Broken unwiding in tarantool_panic_handler'] = _TARANTOOL and + (jit.os == 'OSX'), + ['Disabled on MacOS due to #8652'] = jit.os == 'OSX', + ['Test requires JIT enabled'] = not jit.status(), +}) + +-- XXX: The original issue has 2 ways to crash: +-- 1) in `lj_trace_unwind()` +-- 2) in `lj_trace_exit()` +-- But, since we have an additional GC pressure due to requiring a +-- `tap` module, the second case needs an impossibly big +-- `gcstepmul` value to reproduce the issue. So, since the root +-- issue is the same and now rehashing of finalizer table is +-- omitted, we test only the first case. +test:plan(2) + +local allocinject = require('lj_1247_allocinject') + +local ffi = require('ffi') +ffi.cdef[[ + struct test {int a;}; +]] + +local N_GC_STEPS = 100 +local N_GC_FINALIZERS = 100 + +local function empty() end + +-- Create a chunk like the following: +--[[ + local tostring = tostring + local r = ... + for _ = 1, 4 do + r[1] = tostring(1) + -- ... + r[N_GCSTEPS] = tostring(N_GC_STEPS) + end +--]] +local function create_chunk(n_steps) + local chunk = 'local tostring = tostring\n' + chunk = chunk .. ('local r = ...\n') + chunk = chunk .. 'for _ = 1, 4 do\n' + for i = 1, n_steps do + chunk = chunk .. (' r[%d] = tostring(%d)\n'):format(i, i) + end + chunk = chunk .. 'end\n' + chunk = chunk .. 'return r\n' + return chunk +end + +local function add_more_garbage(size) + return ffi.new('char[?]', size) +end + +-- Helper to skip the atomic phase. +local function skip_atomic() + local first_gc_called = false + local function mark_fin() first_gc_called = true end + jit.off(mark_fin) + debug.getmetatable(newproxy(true)).__gc = mark_fin + + -- Skip the atomic phase. + jit.off() + while not first_gc_called do collectgarbage('step') end + jit.on() +end + +local function crash_on_trace_unwind_gc_setup() + skip_atomic() + collectgarbage('setstepmul', 1000) + add_more_garbage(1024 * 1024) +end + +local f = assert(loadstring(create_chunk(N_GC_STEPS))) + +-- Create a really long trace. +jit.flush() +jit.opt.start('hotloop=2', 'maxirconst=5000', 'maxrecord=10000', 'maxsnap=1000', + '-fold') + +-- luacheck: no unused +local gc_anchor = {} +local function anchor_finalizer(i) + gc_anchor[i] = ffi.gc(ffi.new('struct test', i), empty) +end + +for i = 1, N_GC_FINALIZERS do + anchor_finalizer(i) +end + +-- Record the trace first. +f({}) + +-- The table for anchoring cdata objects. +local res_tab = {} + +collectgarbage() +collectgarbage() +collectgarbage('setpause', 0) +collectgarbage('setstepmul', 1) + +gc_anchor = nil + +crash_on_trace_unwind_gc_setup() + +-- OOM on every allocation (i.e., on finalizer table rehashing +-- too). +allocinject.enable() + +local r, err = pcall(f, res_tab) + +allocinject.disable() + +test:ok(not r, 'correct status') +test:like(err, 'not enough memory', 'correct error message') + +test:done(true) diff --git a/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/CMakeLists.txt b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/CMakeLists.txt new file mode 100644 index 00000000..c3742e45 --- /dev/null +++ b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/CMakeLists.txt @@ -0,0 +1 @@ +BuildTestCLib(lj_1247_allocinject lj_1247_allocinject.c) diff --git a/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/lj_1247_allocinject.c b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/lj_1247_allocinject.c new file mode 100644 index 00000000..81aea60b --- /dev/null +++ b/test/tarantool-tests/lj-1247-fin-tab-rehashing-on-trace/lj_1247_allocinject.c @@ -0,0 +1,49 @@ +#include "lua.h" +#include "lauxlib.h" + +#undef NDEBUG +#include <assert.h> + +static lua_Alloc old_allocf = NULL; +static void *old_alloc_state = NULL; + +/* Function to be used instead of the default allocator. */ +static void *allocf_with_injection(void *ud, void *ptr, size_t osize, + size_t nsize) +{ + /* Always OOM on allocation (not on realloc). */ + if (ptr == NULL) + return NULL; + else + return old_allocf(ud, ptr, osize, nsize); +} + +static int enable(lua_State *L) +{ + assert(old_allocf == NULL); + old_allocf = lua_getallocf(L, &old_alloc_state); + lua_setallocf(L, allocf_with_injection, old_alloc_state); + return 0; +} + +static int disable(lua_State *L) +{ + assert(old_allocf != NULL); + assert(old_allocf != allocf_with_injection); + lua_setallocf(L, old_allocf, old_alloc_state); + old_allocf = NULL; + old_alloc_state = NULL; + return 0; +} + +static const struct luaL_Reg allocinject[] = { + {"enable", enable}, + {"disable", disable}, + {NULL, NULL} +}; + +LUA_API int luaopen_lj_1247_allocinject(lua_State *L) +{ + luaL_register(L, "lj_1247_allocinject", allocinject); + return 1; +} -- 2.46.0
next reply other threads:[~2024-09-02 12:54 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-09-02 12:54 Sergey Kaplun via Tarantool-patches [this message] 2024-09-06 14:42 ` Sergey Bronnikov via Tarantool-patches 2024-09-07 5:15 ` Sergey Kaplun via Tarantool-patches 2024-09-09 13:37 ` Sergey Bronnikov via Tarantool-patches 2024-09-09 14:15 ` Sergey Kaplun via Tarantool-patches 2024-09-19 9:02 ` Maxim Kokryashkin via Tarantool-patches 2024-09-19 11:19 ` [Tarantool-patches] [PATCH luajit] Drop unused function wrapper Sergey Kaplun via Tarantool-patches 2024-09-19 11:30 ` Maxim Kokryashkin via Tarantool-patches
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