Seg fault when closing a db while writing to it

[Yuval-Ariel]

error:

[ RUN      ] DBTest.ShuttingDownNotBlockStalledWrites
Received signal 11 (Segmentation fault)

#4  0x00007fc783ad2827 in rocksdb::DBImpl::PreprocessWrite (this=0x55fc370d06c0, write_options=..., log_context=0x7fc7497f8f50, write_context=0x7fc7497f9310) at db/db_impl/db_impl_write.cc:1254
1254	  log_context->writer = logs_.back().writer;
#5  0x00007fc783acd8aa in rocksdb::DBImpl::WriteImpl (this=0x55fc370d06c0, write_options=..., my_batch=0x7fc7497f96c0, callback=0x0, log_used=0x0, log_ref=0, disable_memtable=false, seq_used=0x0, batch_cnt=0, pre_release_callback=0x0, post_memtable_callback=0x0) at db/db_impl/db_impl_write.cc:391
391	    status = PreprocessWrite(write_options, &log_context, &write_context);
#6  0x00007fc783acc5cb in rocksdb::DBImpl::Write (this=0x55fc370d06c0, write_options=..., my_batch=0x7fc7497f96c0) at db/db_impl/db_impl_write.cc:146
146	    s = WriteImpl(write_options, my_batch, /*callback=*/nullptr,

the main thread has already returned from Close().

reproduce:
on hash 3349f79
in db/db_test.cc, ShuttingDownNotBlockStalledWrites test, change call to CancelAllBackgroundWork(db_, true); into Close();

need to check if its Upstreamable

[Yuval-Ariel]

From looking at the code, it seems that currently its not supported to close the db while theres a live put request in process.
this could be the result of facebook/rocksdb@1e9bf25#diff-d9341fbe2a5d4089b93b22c5ed7f666bc311b378c26d0786f4b50c290e460187 since the db mutex is not protecting the part of the PreprocessWrite anymore.
in any case, i think we need to understand whether its the users responsibility for waiting until the Put operation returns before calling Close() or destroying the db.

any thoughts @Guyme , @hilikspdb ?

i've also raised this issue In the RocksDB repo - facebook/rocksdb#10751 . waiting for their reply

[Yuval-Ariel]

found an answer is rocksdb QnA.:

Q: Is it safe to close RocksDB while another thread is issuing read, write or manual compaction requests?

A: No. The users of RocksDB need to make sure all functions have finished before they close RocksDB. You can speed up the waiting by calling CancelAllBackgroundWork().