Reproducible Kernel - Mempo Project
 

We going to create reproducible kernel which will be more secure then another kernels.
Currently we have problem with reproducible of "vmlinux" file.
When we compilate kernel any times, all files are the same beside file "vmlinux". More about our
"Mempo Project" is on this website: https://wiki.debian.org/ReproducibleBuildsKernel

There is difference between two compilation:

ffffffff8141c162: 00 00 add %al,(%rax)
ffffffff8141c164: 47 rex.RXB
ffffffff8141c165: 4e 55 rex.WRX push %rbp
-ffffffff8141c167: 00 64 ce fe add %ah,-0x2(%rsi,%rcx,8)
-ffffffff8141c16b: 0d 9c ac 80 f6 or $0xf680ac9c,%eax
-ffffffff8141c170: 44 93 rex.R xchg %eax,%ebx
-ffffffff8141c172: 50 push %rax
-ffffffff8141c173: 09 78 a3 or %edi,-0x5d(%rax)
-ffffffff8141c176: 72 2c jb ffffffff8141c1a4 <__start___ex_table+0x24>
-ffffffff8141c178: 02 46 d5 add -0x2b(%rsi),%al
-ffffffff8141c17b: 06 (bad)
+ffffffff8141c167: 00 6c 94 92 add %ch,-0x6e(%rsp,%rdx,4)
+ffffffff8141c16b: 49 c4 rex.WB (bad)
+ffffffff8141c16d: db 48 1e fisttpl 0x1e(%rax)
+ffffffff8141c170: ff (bad)
+ffffffff8141c171: f9 stc
+ffffffff8141c172: ee out %al,(%dx)
+ffffffff8141c173: 63 7e 7a movslq 0x7a(%rsi),%edi
+ffffffff8141c176: b0 fa mov $0xfa,%al
+ffffffff8141c178: 7a c7 jp ffffffff8141c141 <__start_notes+0x141>
+ffffffff8141c17a: 38 2a cmp %ch,(%rdx)

exactly in the section ".notes". If you want see this file go here: https://wiki.debian.org/Reproducible...ence-notes.txt

What is the cause of difference files? Any sugestions what can I do to get same files (reproducible) vmlinuz when I compilate any times my kernel?

It would require more investigation, but it seems that it is the build id. Do you want the build ID to change or you prefer to reset at to have exactly the same image?