Mặc dù Linux kernel được viết chủ yếu bằng C và Assembly nhưng nó cũng sử dụng nhiều công cụ được viết bằng Bash shell và có xài thư viện OpenSSL để mã hóa.
OpenSSL là thư viện mã hóa mã nguồn mở miễn phí được 1 đống phần mềm miễn phí và có phí xài.
Khi biên dịch Linux kernel nó xài OpenSSL để kí tá cho các module và xử lí các chứng chỉ mã hóa bên ngoài đưa vào. Các thư viện mã hóa của OpenSSL cũng giúp tạo ra chìa khóa mã hóa và sinh ra chữ kí số.
Nào bi giờ chúng ta hãy cùng biên dịch Linux kernel mà không cài cắm thư viện OpenSSL coi có sao không nha.
Có báo lỗi nghiêm trọng không tìm thấy header là bio.h khi xài extract-cert nhưng nó vẫn bỏ qua được và chạy tiếp.

Sau đó thì xin dừng cuộc chơi biên dịch Linux kernel tại đây, xin lỗi đời quá đen.

Sau đây là toàn bộ log quá trình biên dịch nhân Linux thiếu thư viện OpenSSL.
# make -j`nproc`
  GEN     arch/x86/include/generated/asm/orc_hash.h
  WRAP    arch/x86/include/generated/uapi/asm/bpf_perf_event.h
  WRAP    arch/x86/include/generated/uapi/asm/errno.h
  WRAP    arch/x86/include/generated/uapi/asm/fcntl.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctl.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctls.h
  WRAP    arch/x86/include/generated/uapi/asm/param.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
  WRAP    arch/x86/include/generated/uapi/asm/ipcbuf.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
  WRAP    arch/x86/include/generated/uapi/asm/poll.h
  WRAP    arch/x86/include/generated/uapi/asm/resource.h
  WRAP    arch/x86/include/generated/uapi/asm/socket.h
  WRAP    arch/x86/include/generated/uapi/asm/sockios.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  WRAP    arch/x86/include/generated/uapi/asm/termbits.h
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  WRAP    arch/x86/include/generated/uapi/asm/termios.h
  WRAP    arch/x86/include/generated/uapi/asm/types.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  WRAP    arch/x86/include/generated/asm/early_ioremap.h
  HOSTCC  arch/x86/tools/relocs_32.o
  WRAP    arch/x86/include/generated/asm/mcs_spinlock.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  WRAP    arch/x86/include/generated/asm/mmzone.h
  WRAP    arch/x86/include/generated/asm/irq_regs.h
  UPD     include/generated/compile.h
  WRAP    arch/x86/include/generated/asm/kmap_size.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  WRAP    arch/x86/include/generated/asm/local64.h
  HOSTCC  arch/x86/tools/relocs_64.o
  WRAP    arch/x86/include/generated/asm/mmiowb.h
  WRAP    arch/x86/include/generated/asm/module.lds.h
  WRAP    arch/x86/include/generated/asm/rwonce.h
  HOSTCC  arch/x86/tools/relocs_common.o
  UPD     include/generated/utsrelease.h
  HOSTCC  scripts/kallsyms
  HOSTCC  scripts/sorttable
  HOSTCC  scripts/selinux/genheaders/genheaders
  HOSTCC  scripts/selinux/mdp/mdp
mkdir -p /root/linux-6.12.5/tools/objtool && make O=/root/linux-6.12.5 subdir=tools/objtool --no-print-directory -C objtool
  HOSTCC  scripts/asn1_compiler
  HOSTLD  arch/x86/tools/relocs
  INSTALL /root/linux-6.12.5/tools/objtool/libsubcmd/include/subcmd/exec-cmd.h
  INSTALL /root/linux-6.12.5/tools/objtool/libsubcmd/include/subcmd/pager.h
  INSTALL /root/linux-6.12.5/tools/objtool/libsubcmd/include/subcmd/run-command.h
  INSTALL /root/linux-6.12.5/tools/objtool/libsubcmd/include/subcmd/parse-options.h
  INSTALL /root/linux-6.12.5/tools/objtool/libsubcmd/include/subcmd/help.h
  INSTALL libsubcmd_headers
  CC      scripts/mod/empty.o
  HOSTCC  scripts/mod/mk_elfconfig
  CC      scripts/mod/devicetable-offsets.s
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/exec-cmd.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/help.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/pager.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/parse-options.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/run-command.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/sigchain.o
  CC      /root/linux-6.12.5/tools/objtool/libsubcmd/subcmd-config.o
  UPD     scripts/mod/devicetable-offsets.h
  MKELF   scripts/mod/elfconfig.h
  HOSTCC  scripts/mod/modpost.o
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/mod/sumversion.o
  HOSTCC  scripts/mod/symsearch.o
  LD      /root/linux-6.12.5/tools/objtool/libsubcmd/libsubcmd-in.o
  AR      /root/linux-6.12.5/tools/objtool/libsubcmd/libsubcmd.a
  CC      /root/linux-6.12.5/tools/objtool/weak.o
  CC      /root/linux-6.12.5/tools/objtool/check.o
  CC      /root/linux-6.12.5/tools/objtool/special.o
  CC      /root/linux-6.12.5/tools/objtool/builtin-check.o
  CC      /root/linux-6.12.5/tools/objtool/arch/x86/special.o
  CC      /root/linux-6.12.5/tools/objtool/elf.o
  CC      /root/linux-6.12.5/tools/objtool/objtool.o
  MKDIR   /root/linux-6.12.5/tools/objtool/arch/x86/lib/
  GEN     /root/linux-6.12.5/tools/objtool/arch/x86/lib/inat-tables.c
  CC      /root/linux-6.12.5/tools/objtool/orc_gen.o
  CC      /root/linux-6.12.5/tools/objtool/orc_dump.o
  CC      /root/linux-6.12.5/tools/objtool/libstring.o
  CC      /root/linux-6.12.5/tools/objtool/arch/x86/orc.o
  CC      /root/linux-6.12.5/tools/objtool/libctype.o
  CC      /root/linux-6.12.5/tools/objtool/str_error_r.o
  HOSTLD  scripts/mod/modpost
  CC      /root/linux-6.12.5/tools/objtool/librbtree.o
  CHKSHA1 include/linux/atomic/atomic-arch-fallback.h
  CC      kernel/bounds.s
  UPD     include/generated/timeconst.h
  CHKSHA1 include/linux/atomic/atomic-instrumented.h
  CHKSHA1 include/linux/atomic/atomic-long.h
  UPD     include/generated/bounds.h
  CC      /root/linux-6.12.5/tools/objtool/arch/x86/decode.o
  CC      arch/x86/kernel/asm-offsets.s
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
  LD      /root/linux-6.12.5/tools/objtool/arch/x86/objtool-in.o
  LD      /root/linux-6.12.5/tools/objtool/objtool-in.o
  LINK    /root/linux-6.12.5/tools/objtool/objtool
  LDS     scripts/module.lds
  HOSTCC  usr/gen_init_cpio
  CC      init/main.o
  CC      certs/system_keyring.o
  CC      mm/mempool.o
  CC      mm/filemap.o
  CC      arch/x86/events/amd/core.o
  CC      arch/x86/entry/vdso/vma.o
  CC      kernel/sched/core.o
  GEN     usr/initramfs_data.cpio
  COPY    usr/initramfs_inc_data
  AS      usr/initramfs_data.o
  AR      usr/built-in.a
  HOSTCC  certs/extract-cert
  CC      kernel/sched/fair.o
certs/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory
   21 | #include <openssl/bio.h>
      |          ^~~~~~~~~~~~~~~
compilation terminated.
make[3]: *** [scripts/Makefile.host:116: certs/extract-cert] Error 1
make[2]: *** [scripts/Makefile.build:478: certs] Error 2
make[2]: *** Waiting for unfinished jobs....
  CC      kernel/sched/build_policy.o
  CC      mm/oom_kill.o
  CC      arch/x86/entry/vdso/extable.o
  CC      arch/x86/events/amd/lbr.o
  UPD     init/utsversion-tmp.h
  CC      init/do_mounts.o
  LDS     arch/x86/entry/vdso/vdso.lds
  AS      arch/x86/entry/vdso/vdso-note.o
  CC      arch/x86/entry/vdso/vclock_gettime.o
  CC      arch/x86/events/amd/ibs.o
  CC      arch/x86/entry/vdso/vgetcpu.o
  CC      mm/fadvise.o
  CC      arch/x86/entry/vdso/vgetrandom.o
  CC      init/do_mounts_initrd.o
  CC      init/initramfs.o
  AS      arch/x86/entry/vdso/vgetrandom-chacha.o
  HOSTCC  arch/x86/entry/vdso/vdso2c
  CC      mm/maccess.o
  LDS     arch/x86/entry/vdso/vdso32/vdso32.lds
  CC      arch/x86/events/amd/uncore.o
  AS      arch/x86/entry/vdso/vdso32/note.o
  AS      arch/x86/entry/vdso/vdso32/system_call.o
  AS      arch/x86/entry/vdso/vdso32/sigreturn.o
  CC      arch/x86/entry/vdso/vdso32/vclock_gettime.o
  CC      init/calibrate.o
  CC      init/init_task.o
  CC      init/version.o
  CC      arch/x86/entry/vdso/vdso32/vgetcpu.o
  CC      arch/x86/entry/vdso/vdso32-setup.o
  CC      mm/page-writeback.o
  CC      kernel/sched/build_utility.o
  CC      arch/x86/events/amd/iommu.o
  VDSO    arch/x86/entry/vdso/vdso64.so.dbg
  AR      init/built-in.a
  CC      arch/x86/events/intel/core.o
  VDSO    arch/x86/entry/vdso/vdso32.so.dbg
  CC      arch/x86/events/intel/bts.o
  CC      arch/x86/events/intel/ds.o
  OBJCOPY arch/x86/entry/vdso/vdso64.so
  OBJCOPY arch/x86/entry/vdso/vdso32.so
  VDSO2C  arch/x86/entry/vdso/vdso-image-64.c
  VDSO2C  arch/x86/entry/vdso/vdso-image-32.c
  CC      arch/x86/entry/vdso/vdso-image-64.o
  CC      arch/x86/entry/vdso/vdso-image-32.o
  CC      arch/x86/events/intel/knc.o
  AR      arch/x86/entry/vdso/built-in.a
  CC      arch/x86/entry/vsyscall/vsyscall_64.o
  AR      arch/x86/events/amd/built-in.a
  CC      arch/x86/events/zhaoxin/core.o
  CC      arch/x86/events/intel/lbr.o
  CC      arch/x86/events/intel/p4.o
  AS      arch/x86/entry/vsyscall/vsyscall_emu_64.o
  CC      mm/folio-compat.o
  AR      arch/x86/entry/vsyscall/built-in.a
  AS      arch/x86/entry/entry.o
  AS      arch/x86/entry/entry_64.o
  CC      arch/x86/entry/syscall_64.o
  AR      arch/x86/events/zhaoxin/built-in.a
  CC      arch/x86/events/core.o
  CC      arch/x86/events/intel/p6.o
  CC      mm/readahead.o
  CC      arch/x86/events/intel/pt.o
  CC      arch/x86/events/intel/uncore.o
  CC      arch/x86/entry/common.o
  CC      arch/x86/events/intel/uncore_nhmex.o
  CC      arch/x86/events/intel/uncore_snb.o
  CC      mm/swap.o
  AR      kernel/sched/built-in.a
  CC      kernel/locking/mutex.o
  AS      arch/x86/entry/thunk.o
  AS      arch/x86/entry/entry_64_compat.o
  CC      arch/x86/entry/syscall_32.o
  CC      arch/x86/events/intel/uncore_snbep.o
  CC      arch/x86/events/probe.o
  CC      arch/x86/events/utils.o
  CC      arch/x86/events/intel/uncore_discovery.o
  CC      arch/x86/events/intel/cstate.o
  CC      arch/x86/events/rapl.o
  AR      arch/x86/entry/built-in.a
  CC      arch/x86/realmode/init.o
  CC      kernel/locking/semaphore.o
  CC      mm/truncate.o
  CC      arch/x86/events/msr.o
  CC      mm/vmscan.o
  CC      mm/shrinker.o
  AS      arch/x86/realmode/rm/header.o
  CC      mm/shmem.o
  AS      arch/x86/realmode/rm/trampoline_64.o
  AS      arch/x86/realmode/rm/stack.o
  AS      arch/x86/realmode/rm/reboot.o
  AS      arch/x86/realmode/rm/wakeup_asm.o
  CC      kernel/locking/rwsem.o
  CC      arch/x86/realmode/rm/wakemain.o
  CC      arch/x86/realmode/rm/video-mode.o
  AS      arch/x86/realmode/rm/copy.o
  CC      mm/util.o
  AS      arch/x86/realmode/rm/bioscall.o
  CC      arch/x86/realmode/rm/regs.o
  CC      arch/x86/realmode/rm/video-vga.o
  CC      arch/x86/realmode/rm/video-vesa.o
  CC      mm/mmzone.o
  AR      arch/x86/events/intel/built-in.a
  CC      arch/x86/realmode/rm/video-bios.o
  AR      arch/x86/events/built-in.a
  CC      arch/x86/kernel/fpu/init.o
  PASYMS  arch/x86/realmode/rm/pasyms.h
  LDS     arch/x86/realmode/rm/realmode.lds
  LD      arch/x86/realmode/rm/realmode.elf
  RELOCS  arch/x86/realmode/rm/realmode.relocs
  OBJCOPY arch/x86/realmode/rm/realmode.bin
  AS      arch/x86/realmode/rmpiggy.o
  CC      arch/x86/kernel/fpu/bugs.o
  AR      arch/x86/realmode/built-in.a
  CC      arch/x86/mm/pat/set_memory.o
  CC      mm/vmstat.o
  CC      kernel/locking/percpu-rwsem.o
  CC      arch/x86/kernel/fpu/core.o
  CC      mm/backing-dev.o
  CC      mm/mm_init.o
  CC      kernel/locking/spinlock.o
  CC      kernel/locking/osq_lock.o
  CC      mm/percpu.o
  CC      mm/slab_common.o
  CC      arch/x86/kernel/fpu/regset.o
  CC      kernel/locking/qspinlock.o
  CC      kernel/locking/rtmutex_api.o
  CC      arch/x86/mm/pat/memtype.o
  CC      mm/compaction.o
  CC      mm/show_mem.o
  CC      kernel/locking/qrwlock.o
  CC      arch/x86/kernel/fpu/signal.o
  CC      arch/x86/mm/pat/memtype_interval.o
  CC      arch/x86/kernel/fpu/xstate.o
  AR      kernel/locking/built-in.a
  CC      kernel/power/qos.o
  CC      mm/interval_tree.o
  CC      mm/list_lru.o
  AR      arch/x86/mm/pat/built-in.a
  CC      arch/x86/mm/init.o
  CC      arch/x86/mm/init_64.o
  CC      mm/workingset.o
  CC      kernel/power/main.o
  CC      mm/debug.o
  AR      arch/x86/kernel/fpu/built-in.a
  CC      mm/gup.o
  CC      arch/x86/kernel/cpu/mce/core.o
  CC      mm/mmap_lock.o
  CC      arch/x86/mm/fault.o
  CC      mm/highmem.o
  CC      arch/x86/mm/ioremap.o
  CC      mm/memory.o
  CC      kernel/power/console.o
  CC      mm/mincore.o
  CC      mm/mlock.o
  CC      arch/x86/mm/extable.o
  CC      kernel/power/process.o
  CC      kernel/power/suspend.o
  CC      arch/x86/kernel/cpu/mce/severity.o
  CC      mm/mmap.o
  CC      mm/mmu_gather.o
  CC      arch/x86/mm/mmap.o
  CC      mm/mprotect.o
  CC      arch/x86/kernel/cpu/mce/genpool.o
  CC      kernel/power/hibernate.o
  CC      kernel/power/snapshot.o
  CC      arch/x86/mm/pgtable.o
  CC      mm/mremap.o
  CC      arch/x86/kernel/cpu/mce/intel.o
  CC      mm/msync.o
  CC      mm/page_vma_mapped.o
  CC      kernel/power/swap.o
  CC      arch/x86/kernel/cpu/mce/amd.o
  CC      arch/x86/mm/physaddr.o
  CC      kernel/power/user.o
  CC      mm/pagewalk.o
  CC      mm/pgtable-generic.o
  CC      arch/x86/mm/tlb.o
  CC      mm/rmap.o
  CC      mm/vmalloc.o
  CC      kernel/power/poweroff.o
  CC      mm/vma.o
  CC      mm/process_vm_access.o
  AR      kernel/power/built-in.a
  CC      kernel/printk/printk.o
  CC      mm/mseal.o
  CC      arch/x86/kernel/cpu/mce/threshold.o
  CC      arch/x86/mm/cpu_entry_area.o
  CC      mm/page_alloc.o
  CC      arch/x86/mm/maccess.o
  CC      mm/init-mm.o
  AR      arch/x86/kernel/cpu/mce/built-in.a
  CC      arch/x86/kernel/cpu/mtrr/mtrr.o
  CC      mm/memblock.o
  CC      mm/slub.o
  CC      arch/x86/mm/pgprot.o
  CC      mm/madvise.o
  CC      arch/x86/mm/hugetlbpage.o
  CC      arch/x86/kernel/cpu/mtrr/if.o
  CC      kernel/printk/printk_safe.o
  CC      arch/x86/mm/dump_pagetables.o
  CC      arch/x86/kernel/cpu/mtrr/generic.o
  CC      mm/page_io.o
  CC      mm/swap_state.o
  CC      kernel/printk/nbcon.o
  CC      mm/swapfile.o
  CC      arch/x86/mm/numa.o
  CC      kernel/printk/printk_ringbuffer.o
  CC      arch/x86/kernel/cpu/mtrr/cleanup.o
  CC      kernel/printk/sysctl.o
  CC      mm/swap_slots.o
  CC      mm/dmapool.o
  CC      mm/hugetlb.o
  CC      arch/x86/mm/numa_64.o
  AR      kernel/printk/built-in.a
  CC      kernel/irq/irqdesc.o
  AR      arch/x86/kernel/cpu/mtrr/built-in.a
  CC      arch/x86/kernel/cpu/microcode/core.o
  CC      kernel/irq/handle.o
  CC      mm/hugetlb_vmemmap.o
  CC      mm/mempolicy.o
  CC      arch/x86/mm/amdtopology.o
  CC      arch/x86/kernel/cpu/microcode/intel.o
  CC      kernel/irq/manage.o
  CC      kernel/irq/spurious.o
  CC      mm/sparse.o
  CC      mm/sparse-vmemmap.o
  CC      arch/x86/mm/srat.o
  CC      kernel/irq/resend.o
  CC      arch/x86/kernel/cpu/microcode/amd.o
  CC      arch/x86/mm/pkeys.o
  CC      mm/mmu_notifier.o
  CC      mm/migrate.o
  CC      kernel/irq/chip.o
  CC      kernel/irq/dummychip.o
  CC      mm/memory-tiers.o
  AR      arch/x86/kernel/cpu/microcode/built-in.a
  CC      arch/x86/kernel/cpu/cacheinfo.o
  CC      arch/x86/mm/kaslr.o
  CC      mm/page_counter.o
  CC      kernel/irq/devres.o
  CC      mm/hugetlb_cgroup.o
  CC      kernel/irq/autoprobe.o
  CC      arch/x86/mm/pti.o
  CC      kernel/irq/irqdomain.o
  CC      mm/early_ioremap.o
  CC      kernel/irq/proc.o
  CC      arch/x86/kernel/cpu/scattered.o
  CC      kernel/irq/migration.o
  CC      mm/numa.o
  CC      mm/numa_memblks.o
  AR      arch/x86/mm/built-in.a
  AR      arch/x86/crypto/built-in.a
  CC      arch/x86/ia32/audit.o
  AR      arch/x86/ia32/built-in.a
  AR      arch/x86/platform/atom/built-in.a
  AR      arch/x86/platform/ce4100/built-in.a
  CC      arch/x86/platform/efi/memmap.o
  CC      arch/x86/kernel/cpu/topology_common.o
  CC      kernel/irq/cpuhotplug.o
  CC      mm/secretmem.o
  CC      kernel/irq/pm.o
  CC      mm/memfd.o
  CC      kernel/irq/msi.o
  CC      mm/ptdump.o
  CC      arch/x86/kernel/cpu/topology_ext.o
  CC      arch/x86/platform/efi/quirks.o
  CC      kernel/irq/affinity.o
  CC      kernel/irq/matrix.o
  CC      mm/execmem.o
  CC      arch/x86/kernel/cpu/topology_amd.o
  CC      arch/x86/kernel/cpu/common.o
  CC      arch/x86/kernel/cpu/rdrand.o
  CC      arch/x86/kernel/cpu/match.o
  CC      arch/x86/kernel/cpu/bugs.o
  AR      mm/built-in.a
  CC      arch/x86/kernel/cpu/aperfmperf.o
  CC      arch/x86/kernel/cpu/cpuid-deps.o
  CC      arch/x86/platform/efi/efi.o
  CC      arch/x86/platform/efi/efi_64.o
  CC      arch/x86/kernel/cpu/umwait.o
  MKCAP   arch/x86/kernel/cpu/capflags.c
  AR      kernel/irq/built-in.a
  CC      kernel/rcu/update.o
  CC      arch/x86/kernel/cpu/powerflags.o
  CC      arch/x86/kernel/cpu/topology.o
  CC      arch/x86/kernel/cpu/proc.o
  CC      arch/x86/kernel/cpu/feat_ctl.o
  AS      arch/x86/platform/efi/efi_stub_64.o
  AS      arch/x86/platform/efi/efi_thunk_64.o
  CC      arch/x86/platform/efi/runtime-map.o
  CC      arch/x86/kernel/cpu/intel.o
  CC      arch/x86/kernel/cpu/tsx.o
  CC      arch/x86/kernel/cpu/intel_epb.o
  CC      arch/x86/kernel/cpu/amd.o
  CC      arch/x86/kernel/cpu/hygon.o
  AR      arch/x86/platform/efi/built-in.a
  AR      arch/x86/platform/geode/built-in.a
  AR      arch/x86/platform/iris/built-in.a
  CC      arch/x86/platform/intel/iosf_mbi.o
  AR      arch/x86/platform/intel-mid/built-in.a
  AR      arch/x86/platform/intel-quark/built-in.a
  AR      arch/x86/platform/olpc/built-in.a
  AR      arch/x86/platform/scx200/built-in.a
  AR      arch/x86/platform/ts5500/built-in.a
  AR      arch/x86/platform/uv/built-in.a
  CC      arch/x86/kernel/cpu/centaur.o
  CC      arch/x86/kernel/cpu/zhaoxin.o
  CC      arch/x86/kernel/cpu/perfctr-watchdog.o
  CC      arch/x86/kernel/cpu/vmware.o
  CC      arch/x86/kernel/cpu/hypervisor.o
  AR      arch/x86/platform/intel/built-in.a
  AR      arch/x86/platform/built-in.a
  CC      arch/x86/kernel/cpu/mshyperv.o
  AR      arch/x86/net/built-in.a
  AR      arch/x86/virt/svm/built-in.a
  AR      kernel/livepatch/built-in.a
  CC      kernel/rcu/sync.o
  AR      arch/x86/virt/vmx/built-in.a
  CC      kernel/dma/mapping.o
  AR      arch/x86/virt/built-in.a
  CC      kernel/dma/direct.o
  CC      arch/x86/kernel/cpu/debugfs.o
  CC      kernel/dma/ops_helpers.o
  CC      kernel/rcu/srcutree.o
  CC      kernel/rcu/tree.o
  CC      kernel/rcu/rcu_segcblist.o
  CC      kernel/dma/swiotlb.o
  CC      kernel/dma/remap.o
  CC      kernel/entry/common.o
  CC      kernel/module/main.o
  CC      kernel/time/time.o
  CC      kernel/time/timer.o
  CC      kernel/time/hrtimer.o
  CC      kernel/entry/syscall_user_dispatch.o
  AR      kernel/dma/built-in.a
  CC      kernel/futex/core.o
  CC      kernel/time/timekeeping.o
  AR      kernel/entry/built-in.a
  CC      kernel/futex/syscalls.o
  CC      kernel/futex/pi.o
  CC      kernel/time/ntp.o
  CC      kernel/time/clocksource.o
  CC      kernel/module/strict_rwx.o
  CC      kernel/futex/requeue.o
  CC      kernel/futex/waitwake.o
  CC      arch/x86/kernel/cpu/capflags.o
  CC      kernel/time/jiffies.o
  AR      arch/x86/kernel/cpu/built-in.a
  CC      arch/x86/kernel/acpi/boot.o
  CC      kernel/time/timer_list.o
  CC      kernel/module/kmod.o
  AR      kernel/rcu/built-in.a
  CC      kernel/cgroup/cgroup.o
  CC      kernel/time/timeconv.o
  CC      kernel/cgroup/rstat.o
  CC      kernel/cgroup/namespace.o
  AR      kernel/futex/built-in.a
  CC      kernel/trace/trace_clock.o
  CC      kernel/time/timecounter.o
  CC      kernel/time/alarmtimer.o
  CC      kernel/time/posix-timers.o
  CC      kernel/module/tree_lookup.o
  CC      arch/x86/kernel/acpi/sleep.o
  CC      kernel/trace/ring_buffer.o
  CC      kernel/cgroup/cgroup-v1.o
  CC      kernel/cgroup/freezer.o
  CC      kernel/module/kallsyms.o
  AS      arch/x86/kernel/acpi/wakeup_64.o
  CC      arch/x86/kernel/acpi/cppc.o
  CC      kernel/time/posix-cpu-timers.o
  CC      kernel/time/posix-clock.o
  CC      kernel/module/procfs.o
  CC      kernel/cgroup/legacy_freezer.o
  CC      arch/x86/kernel/acpi/madt_wakeup.o
  CC      kernel/cgroup/pids.o
  CC      kernel/module/sysfs.o
  CC      kernel/time/itimer.o
  CC      kernel/time/clockevents.o
  CC      kernel/cgroup/rdma.o
  CC      kernel/cgroup/cpuset.o
  AS      arch/x86/kernel/acpi/madt_playdead.o
  CC      arch/x86/kernel/acpi/cstate.o
  AR      kernel/module/built-in.a
  CC      kernel/bpf/core.o
  CC      kernel/cgroup/misc.o
  CC      kernel/time/tick-common.o
  CC      kernel/trace/trace.o
  CC      kernel/cgroup/debug.o
  AR      arch/x86/kernel/acpi/built-in.a
  CC      arch/x86/kernel/apic/apic.o
  CC      kernel/time/tick-broadcast.o
  CC      kernel/time/tick-broadcast-hrtimer.o
  CC      kernel/time/tick-oneshot.o
  CC      kernel/time/tick-sched.o
  CC      kernel/time/timer_migration.o
  CC      kernel/time/vsyscall.o
  AR      kernel/cgroup/built-in.a
  CC      kernel/events/core.o
  CC      kernel/events/ring_buffer.o
  CC      kernel/time/timekeeping_debug.o
  CC      arch/x86/kernel/apic/apic_common.o
  CC      kernel/time/namespace.o
  AR      kernel/bpf/built-in.a
  CC      kernel/fork.o
  CC      kernel/exec_domain.o
  CC      arch/x86/kernel/apic/apic_noop.o
  CC      kernel/events/callchain.o
  CC      kernel/events/hw_breakpoint.o
  AR      kernel/time/built-in.a
  CC      kernel/panic.o
  CC      arch/x86/kernel/apic/ipi.o
  CC      arch/x86/kernel/apic/vector.o
  CC      kernel/events/uprobes.o
  CC      kernel/cpu.o
  CC      arch/x86/kernel/apic/init.o
  CC      kernel/trace/trace_output.o
  CC      kernel/trace/trace_seq.o
  CC      arch/x86/kernel/apic/hw_nmi.o
  CC      kernel/trace/trace_stat.o
  CC      kernel/exit.o
  CC      arch/x86/kernel/apic/io_apic.o
  CC      arch/x86/kernel/apic/msi.o
  CC      arch/x86/kernel/apic/apic_flat_64.o
  CC      kernel/trace/trace_printk.o
  CC      kernel/trace/pid_list.o
  CC      arch/x86/kernel/apic/probe_64.o
  CC      kernel/softirq.o
  CC      kernel/resource.o
  CC      kernel/trace/trace_sched_switch.o
  CC      kernel/trace/trace_nop.o
  AR      arch/x86/kernel/apic/built-in.a
  CC      kernel/sysctl.o
  CC      arch/x86/kernel/kprobes/core.o
  CC      kernel/trace/blktrace.o
  CC      kernel/capability.o
  CC      kernel/trace/trace_events.o
  CC      kernel/ptrace.o
  AR      kernel/events/built-in.a
  CC      kernel/user.o
  CC      kernel/trace/trace_export.o
  CC      arch/x86/kernel/kprobes/opt.o
  CC      kernel/signal.o
  CC      kernel/sys.o
  CC      kernel/trace/trace_event_perf.o
  CC      kernel/umh.o
  CC      kernel/trace/trace_events_filter.o
  CC      kernel/workqueue.o
  AR      arch/x86/kernel/kprobes/built-in.a
  LDS     arch/x86/kernel/vmlinux.lds
  AS      arch/x86/kernel/head_64.o
  CC      arch/x86/kernel/head64.o
  CC      kernel/trace/trace_events_trigger.o
  CC      kernel/pid.o
  CC      kernel/trace/trace_eprobe.o
  CC      arch/x86/kernel/ebda.o
  CC      kernel/trace/trace_kprobe.o
  CC      kernel/task_work.o
  CC      arch/x86/kernel/platform-quirks.o
  CC      kernel/trace/error_report-traces.o
  CC      arch/x86/kernel/process_64.o
  CC      kernel/extable.o
  CC      kernel/params.o
  CC      kernel/kthread.o
  CC      kernel/trace/power-traces.o
  CC      kernel/trace/rpm-traces.o
  CC      kernel/sys_ni.o
  CC      kernel/nsproxy.o
  CC      arch/x86/kernel/signal.o
  CC      kernel/trace/trace_dynevent.o
  CC      kernel/notifier.o
  CC      kernel/ksysfs.o
  CC      kernel/trace/trace_probe.o
  CC      kernel/trace/trace_uprobe.o
  CC      kernel/cred.o
  CC      arch/x86/kernel/signal_64.o
  CC      kernel/reboot.o
  CC      kernel/async.o
  CC      kernel/trace/rethook.o
  CC      kernel/range.o
  CC      kernel/smpboot.o
  CC      kernel/ucount.o
  CC      kernel/regset.o
  CC      arch/x86/kernel/traps.o
  CC      arch/x86/kernel/idt.o
  CC      arch/x86/kernel/irq.o
  CC      kernel/ksyms_common.o
  CC      arch/x86/kernel/irq_64.o
  CC      kernel/groups.o
  CC      kernel/kcmp.o
  AR      kernel/trace/built-in.a
  CC      kernel/freezer.o
  CC      arch/x86/kernel/dumpstack_64.o
  CC      kernel/profile.o
  CC      arch/x86/kernel/time.o
  CC      kernel/stacktrace.o
  CC      kernel/dma.o
  CC      arch/x86/kernel/ioport.o
  CC      arch/x86/kernel/dumpstack.o
  CC      kernel/smp.o
  CC      arch/x86/kernel/nmi.o
  CC      kernel/uid16.o
  CC      kernel/kallsyms.o
  CC      kernel/acct.o
  CC      arch/x86/kernel/ldt.o
  AS      arch/x86/kernel/ibt_selftest.o
  CC      arch/x86/kernel/setup.o
  CC      arch/x86/kernel/x86_init.o
  CC      arch/x86/kernel/i8259.o
  CC      kernel/vmcore_info.o
  CC      kernel/elfcorehdr.o
  CC      kernel/crash_reserve.o
  CC      arch/x86/kernel/irqinit.o
  CC      kernel/kexec_core.o
  CC      arch/x86/kernel/jump_label.o
  CC      kernel/crash_core.o
  CC      arch/x86/kernel/irq_work.o
  CC      kernel/kexec.o
  CC      arch/x86/kernel/probe_roms.o
  CC      kernel/compat.o
  CC      arch/x86/kernel/sys_ia32.o
  CC      arch/x86/kernel/signal_32.o
  CC      kernel/utsname.o
  CC      arch/x86/kernel/sys_x86_64.o
  CC      kernel/pid_namespace.o
  CC      kernel/stop_machine.o
  CC      arch/x86/kernel/espfix_64.o
  CC      kernel/audit.o
  CC      kernel/auditfilter.o
  CC      arch/x86/kernel/ksysfs.o
  CC      arch/x86/kernel/bootflag.o
  CC      arch/x86/kernel/e820.o
  CC      kernel/auditsc.o
  CC      kernel/audit_watch.o
  CC      arch/x86/kernel/pci-dma.o
  CC      arch/x86/kernel/quirks.o
  CC      arch/x86/kernel/kdebugfs.o
  CC      arch/x86/kernel/alternative.o
  CC      kernel/audit_fsnotify.o
  CC      arch/x86/kernel/i8253.o
  CC      arch/x86/kernel/hw_breakpoint.o
  CC      kernel/audit_tree.o
  CC      arch/x86/kernel/tsc.o
  CC      kernel/kprobes.o
  CC      arch/x86/kernel/tsc_msr.o
  CC      kernel/seccomp.o
  CC      kernel/relay.o
  CC      arch/x86/kernel/io_delay.o
  CC      arch/x86/kernel/rtc.o
  CC      kernel/utsname_sysctl.o
  CC      kernel/delayacct.o
  CC      arch/x86/kernel/resource.o
  CC      kernel/taskstats.o
  AS      arch/x86/kernel/irqflags.o
  CC      arch/x86/kernel/static_call.o
  CC      arch/x86/kernel/process.o
  CC      arch/x86/kernel/ptrace.o
  CC      kernel/tsacct.o
  CC      kernel/tracepoint.o
  CC      kernel/irq_work.o
  CC      arch/x86/kernel/tls.o
  CC      kernel/static_call.o
  CC      kernel/static_call_inline.o
  CC      kernel/padata.o
  CC      kernel/jump_label.o
  CC      kernel/context_tracking.o
  CC      arch/x86/kernel/step.o
  CC      arch/x86/kernel/i8237.o
  CC      kernel/iomem.o
  CC      arch/x86/kernel/stacktrace.o
  CC      kernel/rseq.o
  CC      arch/x86/kernel/reboot.o
  CC      arch/x86/kernel/msr.o
  CC      arch/x86/kernel/cpuid.o
  CC      arch/x86/kernel/early-quirks.o
  CC      arch/x86/kernel/smp.o
  CC      arch/x86/kernel/smpboot.o
  CC      arch/x86/kernel/tsc_sync.o
  CC      arch/x86/kernel/setup_percpu.o
  AR      kernel/built-in.a
  CC      arch/x86/kernel/mpparse.o
  CC      arch/x86/kernel/trace_clock.o
  CC      arch/x86/kernel/trace.o
  CC      arch/x86/kernel/rethook.o
  CC      arch/x86/kernel/vmcore_info_64.o
  CC      arch/x86/kernel/machine_kexec_64.o
  AS      arch/x86/kernel/relocate_kernel_64.o
  CC      arch/x86/kernel/crash_dump_64.o
  CC      arch/x86/kernel/crash.o
  CC      arch/x86/kernel/module.o
  CC      arch/x86/kernel/early_printk.o
  CC      arch/x86/kernel/hpet.o
  CC      arch/x86/kernel/amd_nb.o
  CC      arch/x86/kernel/kvm.o
  CC      arch/x86/kernel/kvmclock.o
  CC      arch/x86/kernel/paravirt.o
  CC      arch/x86/kernel/pvclock.o
  CC      arch/x86/kernel/pcspeaker.o
  CC      arch/x86/kernel/check.o
  CC      arch/x86/kernel/uprobes.o
  CC      arch/x86/kernel/perf_regs.o
  CC      arch/x86/kernel/tracepoint.o
  CC      arch/x86/kernel/itmt.o
  CC      arch/x86/kernel/umip.o
  CC      arch/x86/kernel/unwind_orc.o
  CC      arch/x86/kernel/callthunks.o
  CC      arch/x86/kernel/cet.o
  CC      arch/x86/kernel/audit_64.o
  CC      arch/x86/kernel/mmconf-fam10h_64.o
  CC      arch/x86/kernel/vsmp_64.o
  AR      arch/x86/kernel/built-in.a
  AR      arch/x86/built-in.a
make[1]: *** [/root/linux-6.12.5/Makefile:1937: .] Error 2
make: *** [Makefile:224: __sub-make] Error 2
Kết nuận:
Thư viện OpenSSL là cần thiết trong quá trình biên dịch Linux kernel nếu có chọn các chức năng như kí tá cho các module, tạo chìa khóa và sinh ra chữ kí số….

