[BOLT] [hugify] PIE binary crashes on kernels below 5.10

The modified hugify test (pie only) crashes with segfault due to unexpected segment alignment.
The segfault occurs because the right side of a hugified area isn’t mapped into a process address space.
Affected kernel versions are below 5.10 which doesn't include the patch https://github.com/torvalds/linux/commit/ce81bb256a22 .

Test setup
- Env: Ubuntu 18.04, linux kernel 5.4
- Enabled debug logs in hugify.cpp (ENABLE_DEBUG)

GDB logs:

(gdb) r

Starting program: /home/dm/hugify_test/hugify.c.tmp.pie 

[hugify] hot start: 555555f54000

[hugify] hot end: 5555561531a9

[hugify] aligned huge page from: 555555e00000

[hugify] aligned huge page to: 555556200000

[hugify] workaround with memory alignment for kernel < 5.10

[hugify] allocated temporary address: 7ffff75e2000

[hugify] allocated size: 400000


Program received signal SIGSEGV, Segmentation fault.

0x0000555556154460 in ?? ()

(gdb) info proc

process 3067

cmdline = '/home/dm/hugify_test/hugify.c.tmp.pie'

cwd = '/home/dm/hugify_test'

exe = '/home/dm/hugify_test/hugify.c.tmp.pie'

(gdb) shell cat /proc/3067/maps 

555555554000-555555754000 r-xp 00000000 08:01 2493742                    /home/dm/hugify_test/hugify.c.tmp.pie

555555953000-555555954000 r--p 001ff000 08:01 2493742                    /home/dm/hugify_test/hugify.c.tmp.pie

555555954000-555555955000 rw-p 00200000 08:01 2493742                    /home/dm/hugify_test/hugify.c.tmp.pie

555555d54000-555556156000 r-xp 00800000 08:01 2493742                    /home/dm/hugify_test/hugify.c.tmp.pie

7ffff75e2000-7ffff79e2000 rw-p 00000000 00:00 0 

7ffff79e2000-7ffff7bc9000 r-xp 00000000 08:01 2621522                    /lib/x86_64-linux-gnu/libc-2.27.so

7ffff7bc9000-7ffff7dc9000 ---p 001e7000 08:01 2621522                    /lib/x86_64-linux-gnu/libc-2.27.so

7ffff7dc9000-7ffff7dcd000 r--p 001e7000 08:01 2621522                    /lib/x86_64-linux-gnu/libc-2.27.so

7ffff7dcd000-7ffff7dcf000 rw-p 001eb000 08:01 2621522                    /lib/x86_64-linux-gnu/libc-2.27.so

7ffff7dcf000-7ffff7dd3000 rw-p 00000000 00:00 0 

7ffff7dd3000-7ffff7dfc000 r-xp 00000000 08:01 2621446                    /lib/x86_64-linux-gnu/ld-2.27.so

7ffff7fe1000-7ffff7fe3000 rw-p 00000000 00:00 0 

7ffff7ff7000-7ffff7ffa000 r--p 00000000 00:00 0                          [vvar]

7ffff7ffa000-7ffff7ffc000 r-xp 00000000 00:00 0                          [vdso]

7ffff7ffc000-7ffff7ffd000 r--p 00029000 08:01 2621446                    /lib/x86_64-linux-gnu/ld-2.27.so

7ffff7ffd000-7ffff7ffe000 rw-p 0002a000 08:01 2621446                    /lib/x86_64-linux-gnu/ld-2.27.so

7ffff7ffe000-7ffff7fff000 rw-p 00000000 00:00 0 

7ffffffde000-7ffffffff000 rw-p 00000000 00:00 0                          [stack]

ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0                  [vsyscall]

(gdb) 

readelf output (readelf -lW hugify.c.tmp.pie)

Elf file type is DYN (Position-Independent Executable file)

Entry point 0xc00fa0

There are 10 program headers, starting at offset 8388608


Program Headers:

  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align

  PHDR           0x800000 0x0000000000800000 0x0000000000800000 0x000230 0x000230 R   0x8

  INTERP         0x000238 0x0000000000000238 0x0000000000000238 0x00001c 0x00001c R   0x1

      [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]

  LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x1ff868 0x1ff868 R E 0x200000

  LOAD           0x1ffdb8 0x00000000003ffdb8 0x00000000003ffdb8 0x000258 0x000260 RW  0x200000

  LOAD           0x800000 0x0000000000800000 0x0000000000800000 0x401304 0x401304 R E 0x200000

  DYNAMIC        0x1ffdc8 0x00000000003ffdc8 0x00000000003ffdc8 0x0001f0 0x0001f0 RW  0x8

  NOTE           0x000254 0x0000000000000254 0x0000000000000254 0x000044 0x000044 R   0x4

  GNU_EH_FRAME   0xc012a0 0x0000000000c012a0 0x0000000000c012a0 0x000064 0x000064 R   0x4

  GNU_STACK      0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW  0x10

  GNU_RELRO      0x1ffdb8 0x00000000003ffdb8 0x00000000003ffdb8 0x000248 0x000248 R   0x1

 Section to Segment mapping:

  Segment Sections...

   00

   01     .interp

   02     .interp .note.ABI-tag .note.gnu.build-id .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .plt.got .bolt.org.text .fini .rodata .bolt.org.eh_frame_hdr .bolt.org.eh_frame

   03     .init_array .fini_array .dynamic .got .data .bss

   04     .text .text.injected .eh_frame .text.bolt.extra.1 .rodata.str1.1.bolt.extra.1 .rodata.str1.8.bolt.extra.1 .note.gnu.property.bolt.extra.1 .eh_frame.bolt.extra.1 .eh_frame_hdr

   05     .dynamic

   06     .note.ABI-tag .note.gnu.build-id

   07     .eh_frame_hdr

   08

   09     .init_array .fini_array .dynamic .got