centos-stream 9 / fedora 35 do not boot under lx about illumos-omnios

[citrus-it]

If I modify the lx brand so that it does not map lx_vdso, the zone boots and the memory map looks like this:

    7fffef288000     7fffef2c0000            38000 /zones/lx/root/usr/lib/systemd/systemd
    7fffef2c0000     7fffef3af000            ef000 /zones/lx/root/usr/lib/systemd/systemd
    7fffef3af000     7fffef415000            66000 /zones/lx/root/usr/lib/systemd/systemd
    7fffef415000     7fffef45e000            49000 /zones/lx/root/usr/lib/systemd/systemd
    7fffef45e000     7fffef45f000             1000 /zones/lx/root/usr/lib/systemd/systemd
    7fffef460000     7fffef461000             1000 [ unknown ]

and pmap shows the flags:

00007FFFEF288000        224K r----  /zones/lx/root/usr/lib/systemd/systemd
00007FFFEF2C0000        956K r-x--  /zones/lx/root/usr/lib/systemd/systemd
00007FFFEF3AF000        408K r----  /zones/lx/root/usr/lib/systemd/systemd
00007FFFEF415000        292K r----  /zones/lx/root/usr/lib/systemd/systemd
00007FFFEF45E000          4K rw---  /zones/lx/root/usr/lib/systemd/systemd
00007FFFEF460000          4K r--s-

[citrus-it]

The following change in glibc changed the way that the runtime linker decides whether to relocate a section:

commit b413280cfb16834450f66f554bc0d618bb513851
Author: H.J. Lu <[email protected]>
Date:   Thu Sep 16 08:15:29 2021 -0700

    ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]

    We can't relocate entries in dynamic section if it is readonly:

    1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
    section is readonly and set it based on p_flags of PT_DYNAMIC segment.
    2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
    section should be relocated.

and it seems that the lx_vdso.so libraries do have the PF_W flag set on the dynamic section:

bloody:illumos:master% elfedit -re 'phdr:p_flags 2' i386/lx_vdso.so.1

Program header [1]:
    p_vaddr:      0x74        p_flags:    [ PF_X PF_W PF_R ]
    p_paddr:      0           p_type:     [ PT_DYNAMIC ]
    p_filesz:     0x100       p_memsz:    0
    p_offset:     0x74        p_align:    0
bloody:illumos:master% elfedit -re 'phdr:p_flags 2' amd64/lx_vdso.so.1

Program header [1]:
    p_vaddr:      0xe8                p_flags:    [ PF_W PF_R ]
    p_paddr:      0                   p_type:     [ PT_DYNAMIC ]
    p_filesz:     0x200               p_memsz:    0
    p_offset:     0xe8                p_align:    0

Patching these with elfedit to remove the PF_W flag resolves the problem and the lx zone can boot (both centos stream 9 and fedora 35)