Crash observed in CouchKVStore::commitCallback()

Stack Trace of first crash - a7fe9847-4d28-460d-d38b4cb3-233444d1.dmp

Core was generated by `/opt/couchbase/bin/memcached -C /opt/couchbase/var/lib/couchbase/config/memcach'.

 #0  0x00000000007e2546 in PersistenceCallback::operator()(EPTransactionContext&, SingleThreadedRCPtr<Item, Item*, std::default_delete<Item> >, KVStore::FlushStateMutation) ()

 #0  0x00000000007e2546 in PersistenceCallback::operator()(EPTransactionContext&, SingleThreadedRCPtr<Item, Item*, std::default_delete<Item> >, KVStore::FlushStateMutation) ()

 No symbol table info available.

 #1  0x00000000007e2935 in EPTransactionContext::setCallback(SingleThreadedRCPtr<Item, Item*, std::default_delete<Item> > const&, KVStore::FlushStateMutation) ()

 No symbol table info available.

 #2  0x00000000007f3351 in CouchKVStore::commitCallback(std::deque<CouchRequest, std::allocator<CouchRequest> >&, kvstats_ctx&, couchstore_error_t) ()

 No symbol table info available.

 #3  0x0000000000808052 in CouchKVStore::commit(VB::Commit&) ()

 No symbol table info available.

 #4  0x00000000007c0abe in EPBucket::commit(Vbid, KVStore&, VB::Commit&) ()

 No symbol table info available.

 #5  0x00000000007c5f2c in EPBucket::flushVBucket_UNLOCKED(LockedVBucketPtr) ()

 No symbol table info available.

 #6  0x00000000007c621f in EPBucket::flushVBucket(Vbid) ()

 No symbol table info available.

 #7  0x000000000066d850 in Flusher::flushVB() ()

 No symbol table info available.

 #8  0x000000000066e319 in Flusher::step(GlobalTask*) ()

 No symbol table info available.

 #9  0x0000000000670557 in GlobalTask::execute() ()

 No symbol table info available.

 #10 0x000000000066b6a0 in FollyExecutorPool::TaskProxy::scheduleViaCPUPool()::{lambda()#1}::operator()() const ()

 No symbol table info available.

 #11 0x0000000000975560 in folly::ThreadPoolExecutor::runTask(std::shared_ptr<folly::ThreadPoolExecutor::Thread> const&, folly::ThreadPoolExecutor::Task&&) ()

 No symbol table info available.

 #12 0x000000000095d23a in folly::CPUThreadPoolExecutor::threadRun(std::shared_ptr<folly::ThreadPoolExecutor::Thread>) ()

 No symbol table info available.

 #13 0x0000000000978519 in void folly::detail::function::FunctionTraits<void ()>::callBig<std::_Bind<void (folly::ThreadPoolExecutor::*(folly::ThreadPoolExecutor*, std::shared_ptr<folly::ThreadPoolExecutor::Thread>))(std::shared_ptr<folly::ThreadPoolExecutor::Thread>)> >(folly::detail::function::Data&) ()

 No symbol table info available.

 #14 0x0000000000669c2d in void folly::detail::function::FunctionTraits<void ()>::callBig<CBRegisteredThreadFactory::newThread(folly::Function<void ()>&&)::{lambda()#1}>(folly::detail::function::Data&) ()

 No symbol table info available.

 #15 0x00007fc465e78d40 in execute_native_thread_routine () at /tmp/deploy/objdir/../gcc-10.2.0/libstdc++-v3/src/c++11/thread.cc:80

 No locals.

 #16 0x00007fc46567cea5 in start_thread (arg=0x7fc3f1ffb700) at pthread_create.c:307

         __res = <optimized out>

         pd = 0x7fc3f1ffb700

         now = <optimized out>

         unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140479555417856, -519509859033764609, 0, 8392704, 0, 140479555417856, 526278440538254591, 523154533403110655}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}

         not_first_call = <optimized out>

         pagesize_m1 = <optimized out>

         sp = <optimized out>

         freesize = <optimized out>

 #17 0x00007fc4653a58dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

 No locals.

guides/gradlew --refresh-dependencies testrunner -P jython=/opt/jython/bin/jython -P 'args=-i /tmp/testexec.72417.ini -p bucket_storage=couchstore,rerun=false,GROUP=P0;graceful_durability,randomize_value=true,doc_size=256,bucket_eviction_policy=fullEviction,nodes_init=4,graceful=True,collect_pcaps=True,upgrade_version=7.0.0-4987 -t magma.magma_crash_recovery.MagmaCrashTests.test_crash_during_recovery,num_items=5000000,doc_size=1024,graceful=True,sdk_timeout=60,doc_ops=update:delete:expiry,replicas=1,durability=PERSIST_TO_MAJORITY,GROUP=P0;graceful_durability -m rest'