SSD-tier: full sync replication crash or hang master

[zhyhang]

Describe the bug
make full sync replication from a ssd-tier master node (no replica) will crash or hang it.

To Reproduce
Steps to reproduce the behavior:

1. run a single master node (no replica) with ssd-tier opening.
2. write 20,000,000 ~ 30,000,000 to master, string type kv, key len 32 and value 2KB about that will consume 36G ssd storage.
3. start another node (same config as master).
4. replicaof (master ip:port).
5. run not long time, the master will crash or hang.
6. if hang, operation on the replica will output: (error) LOADING Dragonfly is loading the dataset in memory
7. if crash, the master stderr output:

*** SIGFPE received at time=1745151458 on cpu 2 ***
PC: @ 0x5b216091c605 (unknown) mi_free_generic_mt
or
*** SIGSEGV received at time=1745156745 on cpu 1 ***
PC: @ 0x569e90c3df04 (unknown) util::fb2::EventCount::await<>()

Expected behavior
full sync normally then replica transfer to partial replication and working well

Screenshots

Environment (please complete the following information):

• OS: [ubuntu 24.04]
• hang Kernel: Linux ubuntu2404152192 6.8.0-57-generic #59-Ubuntu SMP PREEMPT_DYNAMIC Sat Mar 15 17:40:59 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
• crash Kernal: 6.6.72+ #1 SMP PREEMPT_DYNAMIC Sun Mar 30 09:01:26 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
• Containerized?: [hang testing in IDC Metal's QEMU, crash testing in google cloud vm ]
• Dragonfly Version: [1.28.2]

Reproducible Code Snippet

# Minimal code snippet to reproduce this bug

Additional context

flags-6679.txt

[vyavdoshenko]

@zhyhang
Thanks for reporting the issue.

[romange]

I reproduced it locally with master in debug or opt mode. easily reproduces.

mkdir /tmp/logmaster /tmp/logslave

Master

config:

# Dragonfly Configuration File

--port=6380
--maxmemory=10G
# Enable cache mode (evict keys when near maxmemory)
--cache_mode=true
--proactor_threads=4

# Directory to store log files
--log_dir=/tmp/logmaster
--dbfilename=
--tiered_prefix=/mnt/vol/tiered_master
--tiered_offload_threshold=0.2
--cluster_mode=emulated

and then debug POPULATE 5000000 key 4096

Slave

slave config:

--port=6381
--maxmemory=10G
--cache_mode=true
--proactor_threads=4

# Directory to store log files
--log_dir=/tmp/logslave
--dbfilename=
--tiered_prefix=/mnt/vol/tiered_slave
--tiered_offload_threshold=0.2
--cluster_mode=emulated

Run it via: taskset -c 4-8 ./dragonfly --flagfile ~/slave.conf

and then slaveof localhost 6380

Once the CPU goes down - info replication on slave shows its still in full sync.
info replication on master - is stuck.

debug stacktrace dumps the following (pasted only interesting bits):

I20250620 08:59:20.315248 51328 scheduler.cc:487] ------------ Fiber Dispatched (suspended:523947ms) ------------
0xb2ed88e95c10  std::function<>::operator()()
0xb2ed88e9362c  util::fb2::detail::FiberInterface::ExecuteOnFiberStack()::{lambda()#1}::operator()()
0xb2ed88e948b4  boost::context::detail::fiber_ontop<>()
0xb2ed88e941f8  boost::context::fiber::resume_with<>()
0xb2ed88e92e6c  util::fb2::detail::FiberInterface::SwitchTo()
0xb2ed88e883b8  util::fb2::detail::Scheduler::Preempt()
0xb2ed88166eb8  util::fb2::detail::FiberInterface::Suspend()
0xb2ed881675a8  util::fb2::EventCount::wait()
0xb2ed887a202c  util::fb2::EventCount::await<>()
0xb2ed887a17e8  util::fb2::SharedMutex::lock()
0xb2ed88a8d434  std::lock_guard<>::lock_guard()
0xb2ed88a8b58c  dfly::journal::JournalSlice::UnregisterOnChange()
0xb2ed88a7af6c  dfly::journal::Journal::UnregisterOnChange()
0xb2ed8836f6d0  dfly::SliceSnapshot::FinalizeJournalStream()
0xb2ed88340cac  dfly::RdbSaver::Impl::StopSnapshotting()

I20250620 08:59:20.261518 51328 scheduler.cc:487] ------------ Fiber shard_handler_periodic1 (suspended:523892ms) ---
---------
0xb2ed88e95c10  std::function<>::operator()()
0xb2ed88e9362c  util::fb2::detail::FiberInterface::ExecuteOnFiberStack()::{lambda()#1}::operator()()
0xb2ed88e948b4  boost::context::detail::fiber_ontop<>()
0xb2ed88e941f8  boost::context::fiber::resume_with<>()
0xb2ed88e92e6c  util::fb2::detail::FiberInterface::SwitchTo()
0xb2ed88e883b8  util::fb2::detail::Scheduler::Preempt()
0xb2ed88166eb8  util::fb2::detail::FiberInterface::Suspend()
0xb2ed881675a8  util::fb2::EventCount::wait()
0xb2ed887a2150  util::fb2::EventCount::await<>()
0xb2ed887a18b8  util::fb2::SharedMutex::lock_shared()
0xb2ed8888f03c  dfly::SharedLock<>::SharedLock()
0xb2ed88870548  dfly::DflyCmd::BreakStalledFlowsInShard()
0xb2ed8825cd08  dfly::Service::Init()::{lambda()#1}::operator()()
0xb2ed8827d948  std::__invoke_impl<>()
0xb2ed882795a0  std::__invoke_r<>()


I20250620 08:59:20.261500 51328 scheduler.cc:487] ------------ Fiber heartbeat_periodic1 (suspended:532681ms) -------
-----
0xb2ed88e95c10  std::function<>::operator()()
0xb2ed88e9362c  util::fb2::detail::FiberInterface::ExecuteOnFiberStack()::{lambda()#1}::operator()()
0xb2ed88e948b4  boost::context::detail::fiber_ontop<>()
0xb2ed88e941f8  boost::context::fiber::resume_with<>()
0xb2ed88e92e6c  util::fb2::detail::FiberInterface::SwitchTo()
0xb2ed88e883b8  util::fb2::detail::Scheduler::Preempt()
0xb2ed88166eb8  util::fb2::detail::FiberInterface::Suspend()
0xb2ed881675a8  util::fb2::EventCount::wait()
0xb2ed8821b81c  util::fb2::EventCount::await<>()
0xb2ed88215c30  util::fb2::Future<>::Get()
0xb2ed88371914  dfly::SliceSnapshot::PushSerialized()
0xb2ed883720e0  dfly::SliceSnapshot::ThrottleIfNeeded()
0xb2ed88a8ab78  dfly::journal::JournalSlice::SetFlushMode()
0xb2ed88a7b11c  dfly::journal::Journal::SetFlushMode()
0xb2ed882120bc  dfly::journal::JournalFlushGuard::~JournalFlushGuard()

I20250620 08:59:20.244653 51329 scheduler.cc:487] ------------ Fiber Dispatched (suspended:523877ms) ------------
0xb2ed88e95c10  std::function<>::operator()()
0xb2ed88e9362c  util::fb2::detail::FiberInterface::ExecuteOnFiberStack()::{lambda()#1}::operator()()
0xb2ed88e948b4  boost::context::detail::fiber_ontop<>()
0xb2ed88e941f8  boost::context::fiber::resume_with<>()
0xb2ed88e92e6c  util::fb2::detail::FiberInterface::SwitchTo()
0xb2ed88e883b8  util::fb2::detail::Scheduler::Preempt()
0xb2ed88166eb8  util::fb2::detail::FiberInterface::Suspend()
0xb2ed881675a8  util::fb2::EventCount::wait()
0xb2ed887a202c  util::fb2::EventCount::await<>()
0xb2ed887a17e8  util::fb2::SharedMutex::lock()
0xb2ed88a8d434  std::lock_guard<>::lock_guard()
0xb2ed88a8b58c  dfly::journal::JournalSlice::UnregisterOnChange()
0xb2ed88a7af6c  dfly::journal::Journal::UnregisterOnChange()
0xb2ed8836f6d0  dfly::SliceSnapshot::FinalizeJournalStream()
0xb2ed88340cac  dfly::RdbSaver::Impl::StopSnapshotting()

I20250620 08:59:20.108386 51327 scheduler.cc:487] ------------ Fiber heartbeat_periodic0 (suspended:531536ms) -------
-----
0xb2ed88e95c10  std::function<>::operator()()
0xb2ed88e9362c  util::fb2::detail::FiberInterface::ExecuteOnFiberStack()::{lambda()#1}::operator()()
0xb2ed88e948b4  boost::context::detail::fiber_ontop<>()
0xb2ed88e941f8  boost::context::fiber::resume_with<>()
0xb2ed88e92e6c  util::fb2::detail::FiberInterface::SwitchTo()
0xb2ed88e883b8  util::fb2::detail::Scheduler::Preempt()
0xb2ed88166eb8  util::fb2::detail::FiberInterface::Suspend()
0xb2ed881675a8  util::fb2::EventCount::wait()
0xb2ed8821b81c  util::fb2::EventCount::await<>()
0xb2ed88215c30  util::fb2::Future<>::Get()
0xb2ed88371914  dfly::SliceSnapshot::PushSerialized()
0xb2ed883720e0  dfly::SliceSnapshot::ThrottleIfNeeded()
0xb2ed88a8ab78  dfly::journal::JournalSlice::SetFlushMode()
0xb2ed88a7b11c  dfly::journal::Journal::SetFlushMode()
0xb2ed882120bc  dfly::journal::JournalFlushGuard::~JournalFlushGuard()