Why does Red Hat Linux 7.3, 8.0, and 9 load glibc on address 42000000?
On Red Hat Linux 7.3, 8.0, and 9 the C library is compiled for a fixed address rather than a dynamic address. The constant RedHat has chosen is a little above the default TASK_UNMAPPED_BASE, so even though a few memory mappings have been made before libc is mapped, it can get the address it wants. In most cases this fixed address for libc is a good idea, but it does have a single disadvantage. If you change TASK_UNMAPPED_BASE to get more contiguous address space, the choice of 42000000 is very bad. You can install the source rpm and change this address in the spec file to something else like 07000000, you should also add your initials to the release field so it is always clear that this is a version you changed.
On Red Hat Linux 7.3, 8.0, and 9 the C library is compiled for a fixed address rather than a dynamic address. The constant RedHat has chosen is a little above the default TASK_UNMAPPED_BASE, so even though a few memory mappings have been made before libc is mapped, it can get the address it wants. In most cases this fixed address for libc is a good idea, but it does have a single disadvantage. If you change TASK_UNMAPPED_BASE to get more contiguous address space, the choice of 42000000 is very bad. You can install the source rpm and change this address in the spec file to something else like 07000000, you should also add your initials to the release field so it is always clear that this is a version you changed.
