FaultInjectionTestFS::InjectThreadSpecificReadError() should not corrupt mmaped bytes (#8952)

Summary:
Right now FaultInjectionTestFS::InjectThreadSpecificReadError() might try to corrupt return bytes, but these bytes might be from mmapped files, which would cause segfault. Instead FaultInjectionTestFS::InjectThreadSpecificReadError() should never corrupt data unless it is in caller's buffer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8952

Test Plan: See db_stress still runs and make sure in a test run failurs are still injected in non-mmap cases.

Reviewed By: ajkr, ltamasi

Differential Revision: D31147318

fbshipit-source-id: 9484a64ff2aaa36685557203f449286e694e65f9
main
sdong 3 years ago committed by Facebook GitHub Bot
parent b25f2afeff
commit 7c6a7e8fa8
  1. 8
      utilities/fault_injection_fs.cc

@ -768,7 +768,7 @@ void FaultInjectionTestFS::UntrackFile(const std::string& f) {
}
IOStatus FaultInjectionTestFS::InjectThreadSpecificReadError(
ErrorOperation op, Slice* result, bool direct_io, char* /*scratch*/,
ErrorOperation op, Slice* result, bool direct_io, char* scratch,
bool need_count_increase, bool* fault_injected) {
bool dummy_bool;
bool& ret_fault_injected = fault_injected ? *fault_injected : dummy_bool;
@ -803,11 +803,15 @@ IOStatus FaultInjectionTestFS::InjectThreadSpecificReadError(
*result = Slice();
ctx->message += "inject empty result; ";
ret_fault_injected = true;
} else if (!direct_io && Random::GetTLSInstance()->OneIn(7)) {
} else if (!direct_io && Random::GetTLSInstance()->OneIn(7) &&
scratch != nullptr && result->data() == scratch) {
assert(result);
// With direct I/O, many extra bytes might be read so corrupting
// one byte might not cause checksum mismatch. Skip checksum
// corruption injection.
// We only corrupt data if the result is filled to `scratch`. For other
// cases, the data might not be able to be modified (e.g mmaped files)
// or has unintended side effects.
// For a small chance, set the failure to status but corrupt the
// result in a way that checksum checking is supposed to fail.
// Corrupt the last byte, which is supposed to be a checksum byte

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