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Linear scan crash: divergence #36977

aartbik opened this issue May 15, 2019 · 2 comments


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commented May 15, 2019

Last night Dartfuzz results with two crashes. The first looks like the typical "false" divergence due to allocating too much. We have some plans in our design doc to avoid these cases better.

The second, however, may be something else

Isolate (/b/s/w/itglMuvJ/dart_fuzzVQTSUI) JIT-DebugX64 - JIT-DEPOPTEVERY-ReleaseIA32: !DIVERGENCE! 1.13:348763544 (output=false)

Exhausted heap space, trying to allocate 1176490000016 bytes.
Exhausted heap space, trying to allocate 16807000272 bytes.
Unhandled exception:
Out of Memory
#0      _StringBase._concatRangeNative (dart:core-patch/string_patch.dart:943:34)
#1      _StringBase._interpolate (dart:core-patch/string_patch.dart:857:16)
#2      main (file:///b/s/w/itglMuvJ/dart_fuzzVQTSUI/fuzz.dart:252:69)
#3      _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:300:19)
#4      _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:171:12)
#5 (file:///b/s/w/itglMuvJ/dart_fuzzVQTSUI/fuzz.dart:175:11)
#6 (file:///b/s/w/itglMuvJ/dart_fuzzVQTSUI/fuzz.dart:240:11)
#7      main (file:///b/s/w/itglMuvJ/dart_fuzzVQTSUI/fuzz.dart:248:14)
#8      _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:300:19)
#9      _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:171:12)

Isolate (/b/s/w/itglMuvJ/dart_fuzzGDBAGX) JIT-ReleaseSIMDBC64 - JIT-ReleaseSIMDBC: !DIVERGENCE! 1.13:2331337291 (output=false)


===== CRASH =====
si_signo=Segmentation fault(11), si_code=1, si_addr=0xfe2fd10b
version=2.3.1-edge.6ac6d3ae7df25cfb5fca9030c6d26e831aad22c4 (Wed May 15 01:57:17 2019 +0000) on "linux_dbc"
thread=5620, isolate=main(0x3954700)
  pc 0x01a46fbf fp 0xf62fce78 dart::FlowGraphAllocator::BlockLocation(dart::TemplateLocation<short, dart::FpuRegister>, int, int)
  pc 0x05aa88e8 fp 0xf62fcfb0 Unknown symbol
-- End of DumpStackTrace

@aartbik aartbik self-assigned this May 15, 2019


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commented May 15, 2019

The second issue reproduces for SIMDBC, in debug mode with a better assert failure:

../../runtime/vm/compiler/backend/ 379: error: expected: end < first_use_interval()->start()
version=2.3.1-edge.b0727bd6612ed13aa92e55d127e4b336f17de4b8 (Mon May 13 17:47:11 2019 +0000) on "linux_dbc"
thread=112319, isolate=main(0x3475080)
pc 0x01b7bd7c fp 0xf273d908 dart::Profiler::DumpStackTrace(void*)
-- End of DumpStackTrace

@aartbik aartbik changed the title Memory allocation divergences Linear scan crash: divergence May 20, 2019


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commented May 20, 2019

Happened again in a nightly:

JIT-DebugSIMDBC - JIT-DebugIA32: !DIVERGENCE! 1.13:2028195801 (output=false)

../../runtime/vm/compiler/backend/ 379: error: expected: end < first_use_interval()->start()
version=2.3.1-edge.cc2d5adec943ef02b2c1741857fb3bac5386dee7 (Wed May 15 21:27:19 2019 +0000) on "linux_dbc"
thread=5215, isolate=main(0x2a0e700)
  pc 0x01b4466c fp 0xf62bcc18 dart::Profiler::DumpStackTrace(void*)
-- End of DumpStackTrace

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