Compilation error: implicit declaration of function flush_tlb_mm_range

[patacca]

I've tried compiling the module without success.
This error appears when I launch ./load.sh

rmmod: ERROR: Module afl_snapshot is not currently loaded
env ARCH='x64' LINUX_SYSTEM_MAP='/proc/kallsyms' python3 lookup_symbols.py
make -C '/lib/modules/5.9.9-arch1-1/build' M='/home/patacca/Documenti/Software/AFL-Snapshot-LKM/src' modules
make[1]: Entering directory '/usr/lib/modules/5.9.9-arch1-1/build'
  CC [M]  /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.o
In file included from /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/snapshot.h:92,
                 from /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/task_data.h:4,
                 from /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.c:3:
./arch/x86/include/asm/tlb.h: In function ‘tlb_flush’:
./arch/x86/include/asm/tlb.h:24:2: error: implicit declaration of function ‘flush_tlb_mm_range’; did you mean ‘flush_icache_range’? [-Werror=implicit-function-declaration]
   24 |  flush_tlb_mm_range(tlb->mm, start, end, stride_shift, tlb->freed_tables);
      |  ^~~~~~~~~~~~~~~~~~
      |  flush_icache_range
/home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.c: In function ‘recover_memory_snapshot’:
/home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.c:483:30: warning: unused variable ‘entry’ [-Wunused-variable]
  483 |   pte_t *               pte, entry;
      |                              ^~~~~
/home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.c:481:30: warning: unused variable ‘prev_sp’ [-Wunused-variable]
  481 |   struct snapshot_page *sp, *prev_sp = NULL;
      |                              ^~~~~~~
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:283: /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src/memory.o] Error 1
make[1]: *** [Makefile:1784: /home/patacca/Documenti/Software/AFL-Snapshot-LKM/src] Error 2
make[1]: Leaving directory '/usr/lib/modules/5.9.9-arch1-1/build'
make: *** [Makefile:52: all] Error 2
insmod: ERROR: could not insert module afl_snapshot.ko: Invalid parameters

I've also tried to compile it with CCFLAGS=-Wno-implicit-function-declaration and even though it comiples succesfully when I load the module in the kernel the operating system suddenly freezes.

$ uname -a
Linux patacca-laptop 5.9.9-arch1-1 #1 SMP PREEMPT Wed, 18 Nov 2020 19:52:04 +0000 x86_64 GNU/Linux