Re: [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers

On Mon, May 22, 2023 at 10:33:44PM +0200, Jiri Olsa wrote:

hi, we see broken access to user space with bpf_probe_read/bpf_probe_read_str helpers on arm64 with 5.4 kernel. The problem is that both helpers try to read user memory by calling probe_kernel_read, which seems to work on x86 but fails on arm64.

Has this ever worked on arm64 for the 5.4 kernel tree? If not, it's not really a regression, and so, why not use a newer kernel that has this new feature added to it there?

In other words, what requires you to use the 5.4.y tree and requires feature parity across architectures?

thanks,

greg k-h