FreeBSD 12.2 extra RW program header

[Paul Floyd]

Hi


I see that FreeBSD 12.2 has added an extra RW program header.

Can anyone explain what this does? (My initial guess is things like 
thread mutexes and barriers).

Full details:


12.1

Program Headers:
   Type           Offset             VirtAddr           PhysAddr
                  FileSiz            MemSiz              Flg Align
   PHDR           0x0000000000000040 0x0000000000200040 0x0000000000200040
                  0x0000000000000230 0x0000000000000230  R      0x8
   INTERP         0x0000000000000270 0x0000000000200270 0x0000000000200270
                  0x0000000000000015 0x0000000000000015  R      0x1
       [Requesting program interpreter: /libexec/ld-elf.so.1]
   LOAD           0x0000000000000000 0x0000000000200000 0x0000000000200000
                  0x000000000000086c 0x000000000000086c  R 0x1000
   LOAD           0x0000000000001000 0x0000000000201000 0x0000000000201000
                  0x00000000000006b0 0x00000000000006b0  R E 0x1000
   LOAD           0x0000000000002000 0x0000000000202000 0x0000000000202000
                  0x0000000000001158 0x0000000000002014  RW 0x1000
   DYNAMIC        0x0000000000003028 0x0000000000203028 0x0000000000203028
                  0x0000000000000130 0x0000000000000130  RW     0x8

12.2:

Program Headers:
   Type           Offset             VirtAddr           PhysAddr
                  FileSiz            MemSiz              Flg Align
   PHDR           0x0000000000000040 0x0000000000200040 0x0000000000200040
                  0x0000000000000268 0x0000000000000268  R      0x8
   INTERP         0x00000000000002a8 0x00000000002002a8 0x00000000002002a8
                  0x0000000000000015 0x0000000000000015  R      0x1
       [Requesting program interpreter: /libexec/ld-elf.so.1]
   LOAD           0x0000000000000000 0x0000000000200000 0x0000000000200000
                  0x00000000000008bc 0x00000000000008bc  R 0x1000
   LOAD           0x00000000000008c0 0x00000000002018c0 0x00000000002018c0
                  0x00000000000006c0 0x00000000000006c0  R E 0x1000
   LOAD           0x0000000000000f80 0x0000000000202f80 0x0000000000202f80
                  0x0000000000000158 0x0000000000000158  RW 0x1000


extra header here ->

   LOAD           0x00000000000010d8 0x00000000002040d8 0x00000000002040d8
                  0x0000000000000090 0x00000000000000a8  RW 0x1000

   DYNAMIC        0x0000000000000fa8 0x0000000000202fa8 0x0000000000202fa8
                  0x0000000000000130 0x0000000000000130  RW     0x8


A+

Paul