Segementation fault in prefill phase using Griffin model

Backtrace of GDB:

```
Thread 1 "P0 X00 C005" received signal SIGSEGV, Segmentation fault.
gcpp::N_AVX2::SfpCodec::DecompressAndZeroPad, (void*)0> (num=1280, raw_bf=0x7ffffffe8c00, packed_ofs=, packed=..., dbf=...)
at /home/ufownl/Softwares/gemma.cpp/./compression/sfp-inl.h:354
354 const V8 packed = hn::LoadU(d8, base + i);
(gdb) bt
#0 gcpp::N_AVX2::SfpCodec::DecompressAndZeroPad, (void*)0> (num=1280, raw_bf=0x7ffffffe8c00, packed_ofs=, packed=..., dbf=...)
at /home/ufownl/Softwares/gemma.cpp/./compression/sfp-inl.h:354
#1 gcpp::N_AVX2::CompressTraits::DecompressAndZeroPad, hwy::bfloat16_t> (num=1280, raw=0x7ffffffe8c00, packed_ofs=,
packed=..., d=...) at /home/ufownl/Softwares/gemma.cpp/./compression/compress-inl.h:421
#2 gcpp::N_AVX2::DecompressAndZeroPad, gcpp::SfpStream const, hwy::bfloat16_t> (num=1280, raw=0x7ffffffe8c00, packed_ofs=,
packed=..., d=...) at /home/ufownl/Softwares/gemma.cpp/./compression/compress-inl.h:569
#3 gcpp::N_AVX2::MMPerPackage::DecompressB (B_view=, range_kc=..., row_b=6400,
num_packed_B=, B=..., this=) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:1226
#4 gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(hwy::bfloat16_t*, gcpp::IndexRange const&, gcpp::IndexRange const&, auto:1)#1}::operator()(hwy::bfloat16_t*, gcpp::IndexRange const&, gcpp::IndexRange const&, gcpp::N_AVX2::MMSetPartial) const (this=,
B_storage=B_storage@entry=0x7ffffffe8c00, range_kc=..., range_nc=..., out_tag=...) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:980
#5 0x0000555555c1edff in gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}::operator()(gcpp::IndexRange const&) const::{lambda(gcpp::IndexRange const&)#1}::operator()(gcpp::IndexRange const&) const (range_kc=..., this=)
at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:994
#6 gcpp::IndexRangePartition::VisitFirst(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}::operator()(gcpp::IndexRange const&) const::{lambda(gcpp::IndexRange const&)#1}>(gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}::operator()(gcpp::IndexRange const&) const::{lambda(gcpp::IndexRange const&)#1} const&) const (func=...,
this=) at /home/ufownl/Softwares/gemma.cpp/./util/threading.h:246
#7 gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}::operator()(gcpp::IndexRange const&) const (range_nc=..., this=, this=) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:994
#8 0x0000555555d3421d in gcpp::MMParallel::ForNP(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}>(gcpp::IndexRange const&, unsigned long, unsigned long, unsigned long, gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2} const&)::{lambda(gcpp::IndexRange const&, unsigned long)#1}::operator()(gcpp::IndexRange const&, unsigned long) const
(this=, worker_range=...) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul.h:94
#9 _ZZN4gcpp19ParallelizeOneRangeIZNS_10MMParallel5ForNPIZNKS_6N_AVX212MMPerPackage6DoNT_KINS_9SfpStreamEfEEvRKNS_8ConstMatIT_EEmRKNS_6RowPtrIT0_EEEUlRKNS_10IndexRangeEE0_EEvSJ_mmmRKS8_EUlSJ_mE_EEvRKNS_19IndexRangePartitionERN3hwy10ThreadPoolESM_ENKUlmmE_clEmm (this=, this=, thread=, task=)
at /home/ufownl/Softwares/gemma.cpp/./util/threading.h:296
#10 _ZN3hwy4pool5Tasks11CallClosureIZN4gcpp19ParallelizeOneRangeIZNS3_10MMParallel5ForNPIZNKS3_6N_AVX212MMPerPackage6DoNT_KINS3_9SfpStreamEfEEvRKNS3_8ConstMatIT_EEmRKNS3_6RowPtrIT0_EEEUlRKNS3_10IndexRangeEE0_EEvSN_mmmRKSC_EUlSN_mE_EEvRKNS3_19IndexRangePartitionERNS_10ThreadPoolESQ_EUlmmE_EEvPKvmm (opaque=, task=, worker=)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:540
#11 0x0000555555c1c2b0 in hwy::pool::Tasks::WorkerRunSingle (worker=, this=)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:485
#12 hwy::pool::Tasks::WorkerRun (worker=, this=) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:469
#13 hwy::pool::MainAdapter::operator() (this=, barrier=..., wait=..., spin=...)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:834
#14 0x0000555555da50eb in hwy::pool::FunctorAddBarrier::operator() (wait=..., spin=..., this=)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:765
#15 hwy::pool::FunctorAddWait >::operator() (spin=..., this=)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:732
#16 hwy::CallWithSpin > > (func=..., spin_type=)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/spin.h:321
#17 hwy::pool::CallWithConfig (func=..., config=...) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:788
#18 _ZN3hwy10ThreadPool3RunIZN4gcpp19ParallelizeOneRangeIZNS2_10MMParallel5ForNPIZNKS2_6N_AVX212MMPerPackage6DoNT_KINS2_9SfpStreamEfEEvRKNS2_8ConstMatIT_EEmRKNS2_6RowPtrIT0_EEEUlRKNS2_10IndexRangeEE0_EEvSM_mmmRKSB_EUlSM_mE_EEvRKNS2_19IndexRangePartitionERS0_SP_EUlmmE_EEvmmSP_ (this=0x555556beb500, begin=begin@entry=0, end=, closure=...)
at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:1065
#19 0x0000555555dae84e in gcpp::ParallelizeOneRange(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}>(gcpp::IndexRange const&, unsigned long, unsigned long, unsigned long, gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2} const&)::{lambda(gcpp::IndexRange const&, unsigned long)#1}> (func=..., pool=..., get1=...)
at /home/ufownl/Softwares/gemma.cpp/./util/threading.h:291
#20 gcpp::MMParallel::ForNP(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2}>(gcpp::IndexRange const&, unsigned long, unsigned long, unsigned long, gcpp::N_AVX2::MMPerPackage::DoNT_K(gcpp::ConstMat const&, unsigned long, gcpp::RowPtr const&) const::{lambda(gcpp::IndexRange const&)#2} const&) (func=..., pkg_idx=, inner_tasks=, nx_multiple=, range_np=..., this=)
at /home/ufownl/Softwares/gemma.cpp/./ops/matmul.h:92
#21 gcpp::N_AVX2::MMPerPackage::DoNT_K (C=..., num_packed_B=, B=..., this=0x7fffffff97b0) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:987
#22 gcpp::N_AVX2::MMPerPackage::operator() (this=this@entry=0x7fffffff97b0, B=..., C=...) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:894
#23 0x0000555555df3dfb in gcpp::N_AVX2::MMImpl::DoMatMul(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1}::operator()(unsigned long) const (this=0x7fffffff9940, pkg_idx=pkg_idx@entry=0) at /home/ufownl/Softwares/gemma.cpp/./util/mat.h:124
#24 0x0000555555df4aef in gcpp::MMParallel::ForPkg(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1}>(unsigned long, gcpp::N_AVX2::MMImpl::DoMatMul(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1} const&)::{lambda(unsigned long, unsigned long)#1}::operator()(unsigned long, unsigned long) const (this=0x7fffffff9938, task=0, pkg_idx=0) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul.h:72
#25 hwy::ThreadPool::Run(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1}>(unsigned long, gcpp::N_AVX2::MMImpl::DoMatMul(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1} const&)::{lambda(unsigned long, unsigned long)#1}> (this=, begin=, end=1, closure=...) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/contrib/thread_pool/thread_pool.h:1044
#26 0x0000555555df5446 in gcpp::MMParallel::ForPkg(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1}>(unsigned long, gcpp::N_AVX2::MMImpl::DoMatMul(gcpp::MatPtrT const&, gcpp::ConstMat const&, gcpp::RowPtr const&, gcpp::MMArgs const&, gcpp::MMConfig const&)::{lambda(unsigned long)#1} const&) (this=, func=..., max_packages=) at /usr/include/c++/9/bits/stl_vector.h:915
#27 gcpp::N_AVX2::MMImpl::DoMatMul (A=..., B=..., C=..., args=..., config=...) at /home/ufownl/Softwares/gemma.cpp/./ops/matmul-inl.h:1274
#28 0x0000555555df58a6 in gcpp::N_AVX2::MatMul (A=..., B=..., add=, env=..., C=...) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/timer.h:197
#29 0x0000555555df61ea in gcpp::N_AVX2::MatMul (A=..., B=..., add=, env=..., C=...) at /home/ufownl/Softwares/gemma.cpp/./util/mat.h:147
#30 0x0000555555df62a0 in gcpp::N_AVX2::FFWNoVit (activations=..., layer_weights=layer_weights@entry=0x55577e0dc000) at /home/ufownl/Softwares/gemma.cpp/./util/mat.h:440
#31 0x0000555555df667d in gcpp::N_AVX2::TransformerLayer (queries_pos=..., queries_prefix_end=..., num_tokens=num_tokens@entry=12, cache_layer_idx=cache_layer_idx@entry=0, layer_weights=0x55577e0dc000, activations=..., div_seq_len=..., kv_caches=...) at /home/ufownl/Softwares/gemma.cpp/./ops/ops-inl.h:493
#32 0x0000555555df6b63 in gcpp::N_AVX2::Prefill (queries_prompt=..., queries_pos=..., queries_prefix_end=..., query_idx_start=query_idx_start@entry=0, weights=..., activations=..., runtime_config=..., div_seq_len=..., kv_caches=...) at /usr/include/c++/9/bits/stl_vector.h:1058
#33 0x0000555555df7635 in gcpp::N_AVX2::GenerateT (model=..., weights=..., activations=..., runtime_config=..., queries_prompt=..., queries_pos_in=..., queries_prefix_end=..., query_idx_start=0, kv_caches=..., timing_info=...) at /home/ufownl/Softwares/gemma.cpp/./util/mat.h:122
#34 0x0000555555df8302 in gcpp::N_AVX2::GenerateSingleT (model=..., weights=..., runtime_config=..., prompt=..., pos=, prefix_end=, kv_cache=..., env=0x7fffffffd5d0, timing_info=...) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/aligned_allocator.h:273
#35 0x00005555555a34fb in gcpp::Gemma::::operator() > > (weights=std::unique_ptr> = {...}, __closure=) at /usr/include/c++/9/bits/unique_ptr.h:360
#36 gcpp::WeightsOwner::CallT > (func=..., this=0x7fffffffd9c8) at /home/ufownl/Softwares/gemma.cpp/./gemma/weights.h:621
#37 gcpp::Gemma::Generate (this=0x7fffffffd7f0, runtime_config=..., prompt=..., pos=0, prefix_end=0, kv_cache=..., timing_info=...) at /home/ufownl/Softwares/gemma.cpp/gemma/gemma.cc:116
#38 0x0000555555576703 in gcpp::ReplGemma (threading=..., inference=..., gemma=..., kv_cache=...) at /home/ufownl/Softwares/gemma.cpp/build/_deps/highway-src/hwy/aligned_allocator.h:273
#39 0x0000555555576ff7 in gcpp::Run (loader=..., threading=..., inference=...) at /home/ufownl/Softwares/gemma.cpp/gemma/run.cc:288
#40 0x0000555555574a56 in main (argc=, argv=) at /home/ufownl/Softwares/gemma.cpp/gemma/run.cc:307
```