Auto deduplication on restore does not work in this fork

[rvansa]

Trying out the criu restore --auto-dedup feature fails with this fork:

When using on the first restore (doesn't make much sense):

$ sleep 3600 & export PID=$!
[1] 676638
rvansa@rvansa:/tmp$ criu dump -D /tmp/s1 -t $PID --shell-job
Warn  (compel/arch/x86/src/lib/infect.c:352): Will restore 676638 with interrupted system call
[1]+  Killed                  sleep 3600
rvansa@rvansa:/tmp$ criu restore -D /tmp/s1 -d --shell-job --auto-dedup
pie: 676638: Error (criu/pie/util-vdso.c:92): vdso: ELF header magic mismatch
pie: 676638: Error (criu/pie/restorer.c:2056): Restorer fail 676638
Error (criu/cr-restore.c:2593): Restoring FAILED.
Error (criu/cr-restore.c:1536): 676638 exited, status=1

but actually if I do one a normal restore and second dump, the next restore fails with the same error.

I managed to dump/restore twice when using --auto-dedup with dump.

[rvansa]

I can run restore with --auto-dedup using the 'official' version 3.17.1

[rvansa]

For the record, I can dump with -crac version and restore with 3.17.1. Logs with -v4 don't show anything unexpectedly different until loading VDSO:

< pie: 686159: vdso: Parsing at 0x7fff907b8000 0x7fff907ba000
< pie: 686159: vdso: PT_LOAD p_vaddr: 0x0
< pie: 686159: vdso: DT_HASH: 0x120
< pie: 686159: vdso: DT_STRTAB: 0x300
< pie: 686159: vdso: DT_SYMTAB: 0x1c8
< pie: 686159: vdso: DT_STRSZ: 0x8b
< pie: 686159: vdso: DT_SYMENT: 0x18
< pie: 686159: vdso: nbucket 0x3 nchain 0xd bucket 0x7fff907b8128 chain 0x7fff907b8134
< pie: 686159: vdso: image [vdso] 0x7fff907b8000-0x7fff907ba000 [vvar] 0x7fff907b4000-0x7fff907b8000
< pie: 686159: vdso: Runtime vdso/vvar matches dumpee, remap inplace
< pie: 686159: vdso: Remap rt-vdso 0x2e000 -> 0x7fff907b8000
< pie: 686159: vdso: Remap rt-vvar 0x2a000 -> 0x7fff907b4000
< pie: 686159: vdso: Using gettimeofday() on vdso at 0x7fff907b8c50
< pie: 686159: Restoring scheduler params 0.0.0
< pie: 686159: rseq: rseq_abi_pointer = 0x7f713b5f00e0 signature = 0x53053053
< pie: 686159: 686159: Restored
.... vs. ....
> pie: 685311: vdso: Parsing at 0x7ffeaf8e7000 0x7ffeaf8e9000
> pie: 685311: Error (criu/pie/util-vdso.c:92): vdso: ELF header magic mismatch
> pie: 685311: Error (criu/pie/restorer.c:2056): Restorer fail 685311
> Error (criu/cr-restore.c:2593): Restoring FAILED.
> Error (criu/cr-restore.c:1536): 685311 exited, status=1

[rvansa]

I found that the difference is due to mmaping files by default in -crac; with explicit --no-mmap-page-image the --auto-dedup works. So we should check for these flags and make them incompatible - it does not make sense to punch hole into file when it's mmap, unless we break the association.