Comment 5 for bug 2056762

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Dimitry Andric ( wrote :

It's indeed the bump of vm.mmap_rnd_bits from 28 to 32, which is part of the changelog in :

  * test_021_aslr_dapper_libs from ubuntu_qrt_kernel_security failed on K-5.19 /
    J-OEM-6.1 / J-6.2 AMD64 (LP: #1983357)
    - [Config]: set ARCH_MMAP_RND_{COMPAT_, }BITS to the maximum

On my amd64 6.5.0-21-generic machines, the default value is:

vm.mmap_rnd_bits = 28

while on 6.5.0-25-generic, it is:

vm.mmap_rnd_bits = 32

Forcing vm.mmap_rnd_bits back to 28 on 6.5.0-25-generic makes ThreadSanitizer work again.

I'm unsure if this bug should be kept open now, since it is maybe expected that some user space programs break due to the changed randomization settings?