Hello,
I have embedded v8 into a project for the company I work for, and during
some stress tests, I've encountered a weird out-of-memory error. After
considerable investigation, I still have no idea of what might be going on,
so I'm reaching out to you in hope of some insight.
So here is a summary of the scenario: in each test iteration, I create an
Isolate, run some short JS code fragments, and then destroy the isolate.
After the execution of each code fragment, I perform some variable
manipulations from my C++ code using V8's API, prior to running the next
fragment. I repeat thousands of such iterations over the same input (it's
valid), and I expect no memory leaks and no crashes. However, after about 3
hours, V8 crashes with an out-of-memory error of no apparent reason.
I have run the code though valgrind and using address sanitizing, and no
memory leaks were detected. Additionally, I monitor memory consumption
throughout the test; the program's memory usage is stable, without any
peak, and when V8 crashes the system has a lot of available memory (more
than 5 Gib). I have used V8's API to get heap usage statistics after each
successful iteration; the values are always the same, and are shown below
(they are included in an attached file, typical_memory.txt):
ScriptEngine::Run: finished running at 2017-05-05T13:20:34
used_heap_size : 46.9189 Mib
total_heap_size : 66.1562 Mib
Space 0
name : new_space
size : 8 Mib
used_size : 2.47314 Mib
available_size : 5.39404 Mib
Space 1
name : old_space
size : 39.5625 Mib
used_size : 31.6393 Mib
available_size : 5.51526 Mib
Space 2
name : code_space
size : 10.4375 Mib
used_size : 6.16919 Mib
available_size : 0 B
Space 3
name : map_space
size : 8.15625 Mib
used_size : 6.63733 Mib
available_size : 80 B
Space 4
name : large_object_space
size : 0 B
used_size : 0 B
available_size : 11.1015 Gib
When V8 crashes, it prints a heap summary, which I'm sending attached (file
heap_after_error.txt). I also save a core dump. Sometimes, the system
crashes during the creation of an Isolate; sometimes, during the creation
of a Context; typically, it crashes during snapshot deserialization.
However, the top of the stack is always the same, and it's reproduced below
(also included attached, file stacktrace.txt).
#7 v8::internal::OS::Abort () at
../../src/base/platform/platform-posix.cc:230
#8 0x00007ff15a2f922f in v8::Utils::ReportOOMFailure
(location=0x7ff15b20f62e "Committing semi space failed.",
is_heap_oom=false) at ../../src/api.cc:381
#9 0x00007ff15a2f918e in v8::internal::V8::FatalProcessOutOfMemory
(location=0x7ff15b20f62e "Committing semi space failed.",
is_heap_oom=false) at ../../src/api.cc:352
#10 0x00007ff15aa3fefc in v8::internal::Heap::EnsureFromSpaceIsCommitted
(this=0x7ff12c0bdde0) at ../../src/heap/heap.cc:1234
#11 0x00007ff15aa3ed34 in v8::internal::Heap::PerformGarbageCollection
(this=0x7ff12c0bdde0, collector=v8::internal::MARK_COMPACTOR,
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:1308
#12 0x00007ff15aa3e2ab in v8::internal::Heap::CollectGarbage
(this=0x7ff12c0bdde0, collector=v8::internal::MARK_COMPACTOR,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
collector_reason=0x7ff15b20f07a "GC in old space requested",
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:1002
#13 0x00007ff15a33cdee in v8::internal::Heap::CollectGarbage
(this=0x7ff12c0bdde0, space=v8::internal::OLD_SPACE,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
callbackFlags=v8::kNoGCCallbackFlags) at ../../src/heap/heap-inl.h:681
#14 0x00007ff15aa3d069 in v8::internal::Heap::CollectAllGarbage
(this=0x7ff12c0bdde0, flags=2,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:848
#15 0x00007ff15aa3fe84 in v8::internal::Heap::ReserveSpace
(this=0x7ff12c0bdde0, reservations=0x7ff148fe6078, maps=0x7ff148fe60f8) at
../../src/heap/heap.cc:1215
In the heap summary that gets printed, I have noted some apparent
discrepancies with the typical data I get from the API (shown above): for
example, the summary says the size of the old space is 4067328 bytes (=
3.88 Mib), not the typical 39.56 Mib I get from the API.
I have dived into V8 garbage collection, but still couldn't make sense of
the error message ("Committing semi space failed"). So, I'd like to know
under which circumstances this error can happen, and how it's possible that
it only happens occasionally, given that each test iteration is identical
to the others and there is no detectable memory leaks.
If you need more information, please tell me, and I'll be glad to provide
it.
Thank you very much in advance.
Andre
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>>>>>> =============== Before GC (1) =============== >>>>>>
old_generation_allocation_limit_ 734003200
Number of handles : 1240
Global Handle Statistics:
allocated memory = 0B
# weak = 0
# pending = 0
# near_death = 0
# free = 0
# total = 0
Heap statistics : capacity: 1501560832 , used: 9961472, available: %99
To space : capacity: 1048576, available: 792760, %75
Object Histogram:
ONE_BYTE_STRING_TYPE 215 ( 7824 bytes)
EXTERNAL_ONE_BYTE_STRING_TYPE 21 ( 840 bytes)
FOREIGN_TYPE 282 ( 4512 bytes)
FIXED_ARRAY_TYPE 844 ( 199736 bytes)
JS_GLOBAL_PROXY_TYPE 22 ( 880 bytes)
JS_API_OBJECT_TYPE 132 ( 4144 bytes)
JS_OBJECT_TYPE 255 ( 12480 bytes)
JS_ARRAY_TYPE 18 ( 576 bytes)
JS_FUNCTION_TYPE 21 ( 1512 bytes)
Old space : capacity: 4067328, waste: 0, available: 651328, %16
Object Histogram:
ONE_BYTE_INTERNALIZED_STRING_TYPE 988 ( 38936 bytes)
ONE_BYTE_STRING_TYPE 1058 ( 119560 bytes)
CONS_ONE_BYTE_STRING_TYPE 10 ( 400 bytes)
SHORT_EXTERNAL_ONE_BYTE_STRING_TYPE 18 ( 576 bytes)
SYMBOL_TYPE 53 ( 1696 bytes)
HEAP_NUMBER_TYPE 23 ( 368 bytes)
ODDBALL_TYPE 12 ( 576 bytes)
FOREIGN_TYPE 165 ( 2640 bytes)
BYTE_ARRAY_TYPE 1216 ( 49896 bytes)
FIXED_INT8_ARRAY_TYPE 1 ( 32 bytes)
FIXED_UINT8_ARRAY_TYPE 1 ( 32 bytes)
FIXED_INT16_ARRAY_TYPE 1 ( 32 bytes)
FIXED_UINT16_ARRAY_TYPE 1 ( 32 bytes)
FIXED_INT32_ARRAY_TYPE 1 ( 32 bytes)
FIXED_UINT32_ARRAY_TYPE 1 ( 32 bytes)
FIXED_FLOAT32_ARRAY_TYPE 1 ( 32 bytes)
FIXED_FLOAT64_ARRAY_TYPE 1 ( 32 bytes)
FIXED_UINT8_CLAMPED_ARRAY_TYPE 1 ( 32 bytes)
ACCESSOR_INFO_TYPE 105 ( 6720 bytes)
ACCESSOR_PAIR_TYPE 987 ( 23688 bytes)
CALL_HANDLER_INFO_TYPE 57 ( 1824 bytes)
FUNCTION_TEMPLATE_INFO_TYPE 122 ( 19520 bytes)
OBJECT_TEMPLATE_INFO_TYPE 65 ( 4160 bytes)
ALLOCATION_SITE_TYPE 105 ( 5880 bytes)
SCRIPT_TYPE 27 ( 3456 bytes)
TYPE_FEEDBACK_INFO_TYPE 8 ( 256 bytes)
FIXED_ARRAY_TYPE 7412 ( 1690296 bytes)
SHARED_FUNCTION_INFO_TYPE 883 ( 141280 bytes)
CELL_TYPE 76 ( 1216 bytes)
WEAK_CELL_TYPE 4185 ( 100440 bytes)
TRANSITION_ARRAY_TYPE 231 ( 15624 bytes)
PROPERTY_CELL_TYPE 2199 ( 70368 bytes)
PROTOTYPE_INFO_TYPE 105 ( 5880 bytes)
JS_GLOBAL_OBJECT_TYPE 42 ( 1680 bytes)
JS_VALUE_TYPE 63 ( 2016 bytes)
JS_OBJECT_TYPE 1365 ( 65520 bytes)
JS_ARRAY_TYPE 42 ( 1344 bytes)
JS_MAP_TYPE 21 ( 672 bytes)
JS_FUNCTION_TYPE 14389 ( 1036008 bytes)
STRING_TYPE 2074 ( 159472 bytes)
Code space : capacity: 1306624, waste: 0, available: 0, %0
Object Histogram:
CODE_TYPE 1105 ( 805120 bytes)
Map space : capacity: 1042944, waste: 0, available: 80, %0
Object Histogram:
MAP_TYPE 7935 ( 698280 bytes)
Large object space : size: 0
number of objects 0, size of objects 0
>>>>>> ========================================= >>>>>>
<--- Last few GCs --->
<--- JS stacktrace --->
#7 v8::internal::OS::Abort () at ../../src/base/platform/platform-posix.cc:230
#8 0x00007ff15a2f922f in v8::Utils::ReportOOMFailure (location=0x7ff15b20f62e
"Committing semi space failed.", is_heap_oom=false) at ../../src/api.cc:381
#9 0x00007ff15a2f918e in v8::internal::V8::FatalProcessOutOfMemory
(location=0x7ff15b20f62e "Committing semi space failed.", is_heap_oom=false) at
../../src/api.cc:352
#10 0x00007ff15aa3fefc in v8::internal::Heap::EnsureFromSpaceIsCommitted
(this=0x7ff12c0bdde0) at ../../src/heap/heap.cc:1234
#11 0x00007ff15aa3ed34 in v8::internal::Heap::PerformGarbageCollection
(this=0x7ff12c0bdde0, collector=v8::internal::MARK_COMPACTOR,
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:1308
#12 0x00007ff15aa3e2ab in v8::internal::Heap::CollectGarbage
(this=0x7ff12c0bdde0, collector=v8::internal::MARK_COMPACTOR,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
collector_reason=0x7ff15b20f07a "GC in old space requested",
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:1002
#13 0x00007ff15a33cdee in v8::internal::Heap::CollectGarbage
(this=0x7ff12c0bdde0, space=v8::internal::OLD_SPACE,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
callbackFlags=v8::kNoGCCallbackFlags) at ../../src/heap/heap-inl.h:681
#14 0x00007ff15aa3d069 in v8::internal::Heap::CollectAllGarbage
(this=0x7ff12c0bdde0, flags=2,
gc_reason=v8::internal::GarbageCollectionReason::kDeserializer,
gc_callback_flags=v8::kNoGCCallbackFlags) at ../../src/heap/heap.cc:848
#15 0x00007ff15aa3fe84 in v8::internal::Heap::ReserveSpace
(this=0x7ff12c0bdde0, reservations=0x7ff148fe6078, maps=0x7ff148fe60f8) at
../../src/heap/heap.cc:1215
ScriptEngine::Run: finished running at 2017-05-05T13:20:34
used_heap_size : 46.9189 Mib
total_heap_size : 66.1562 Mib
Space 0
name : new_space
size : 8 Mib
used_size : 2.47314 Mib
available_size : 5.39404 Mib
Space 1
name : old_space
size : 39.5625 Mib
used_size : 31.6393 Mib
available_size : 5.51526 Mib
Space 2
name : code_space
size : 10.4375 Mib
used_size : 6.16919 Mib
available_size : 0 B
Space 3
name : map_space
size : 8.15625 Mib
used_size : 6.63733 Mib
available_size : 80 B
Space 4
name : large_object_space
size : 0 B
used_size : 0 B
available_size : 11.1015 Gib
